May Arna Godaker Risberg

• Hibbert, Elsie; Warholm, Kristian Marstrand; Ageberg, Eva; Pålsson, Anders; Kemp, Joanne L. & Risberg, May Arna (2026). Evaluating a 3-Month Physical Impairment and Functional Performance-Based Rehabilitation Program After Hip Arthroscopy for Femoroacetabular Impingement (FAI) Syndrome. Journal of Orthopaedic and Sports Physical Therapy. ISSN 0190-6011. 56(7), p. 456–464. doi: 10.2519/jospt.2026.13775. Full text in Research Archive
• Jacobsen, Julie Sandell; O’brien, Michael J.M.; Christensen, Jeanette R.; Risberg, May Arna; Madsen, Gitte H. & Wallis, Andrew K. [Show all 8 contributors for this article] (2025). Tailoring Rehabilitation Following Periacetabular Osteotomy for Acetabular Dysplasia: A Qualitative Interview Study on Challenges and Opportunities among Physiotherapists in Denmark and Australia. International Journal of Sports Physical Therapy. 20(7), p. 1006–1017. doi: 10.26603/001c.140883. Full text in Research Archive
• Lundquist, Henriette Killingrød; Øiestad, Britt Elin; Sexton, Joseph; Risberg, May Arna & Østerås, Nina (2025). Minimal important change of the knee injury and osteoarthritis outcome score in patients with mild to moderate knee osteoarthritis – using three different anchor-based methods. Osteoarthritis and Cartilage Open. 7(4). doi: 10.1016/j.ocarto.2025.100699. Full text in Research Archive
• Urhausen, Anouk; Pedersen, Marie; Grindem, Hege; Ito, Naoaki; Arhos, Elanna K. & Gunderson, Ragnhild B. [Show all 13 contributors for this article] (2025). Clinical, Functional, Sports Participation, and Osteoarthritis Outcomes After ACL Injury: Ten-Year Follow-up Study of the Delaware-Oslo ACL Cohort Treatment Algorithm. Journal of Bone and Joint Surgery. American volume. ISSN 0021-9355. doi: 10.2106/JBJS.24.00243. Full text in Research Archive
• Cronström, Anna; Risberg, May Arna; Englund, Martin; Strauss, Dorthe B.; Neuman, Paul & Tiderius, Carl Johan [Show all 7 contributors for this article] (2025). Symptoms indicative of early knee osteoarthritis after ACL reconstruction: descriptive analysis of the SHIELD cohort. Osteoarthritis and Cartilage Open. 7(1). doi: 10.1016/j.ocarto.2025.100576. Full text in Research Archive
• Duong, Vicky; Shaheed, Christina Abdel; Ferreira, Manuela L.; Narayan, Sujita W.; Venkatesha, Venkatesha & Hunter, David J. [Show all 29 contributors for this article] (2025). Risk factors for the development of knee osteoarthritis across the lifespan: A systematic review and meta-analysis. Osteoarthritis and Cartilage. ISSN 1063-4584. doi: 10.1016/j.joca.2025.03.003. Full text in Research Archive
• Arhos, Elanna K.; Smith, Angela H.; Ito, Naoaki; Risberg, May Arna; Snyder-Mackler, Lynn & Silbernagel, Karin Grävare (2025). Use of the Uninvolved Limb as Comparator When Calculating Return to Sports Hop Test Symmetry After ACL Reconstruction. Sports Health: A Multidisciplinary Approach (SPH). ISSN 1941-7381. doi: 10.1177/19417381251334639. Full text in Research Archive
• Svinøy, Odd-Einar; Nordbø, Jakob Vangen; Pripp, Are Hugo; Risberg, May Arna; Bergland, Astrid & Borgen, Pål Oliver [Show all 7 contributors for this article] (2025). The effect of prehabilitation for older patients awaiting total hip replacement. A randomized controlled trial with long-term follow up. BMC Musculoskeletal Disorders. 26(1). doi: 10.1186/s12891-025-08468-4. Full text in Research Archive Show summary

  Background Prehabilitation involving a planned exercise program before surgery is proposed to improve rehabilitation and postoperative outcomes. However, the current evidence on the efficacy of prehabilitation for patients awaiting total hip replacement is conflicting. The aim of this study was to evaluate efficacy of preoperative exercises and education (AktivA®) for adults 70 years or older awaiting total hip replacement. Methods In a two-armed randomized controlled trial we recruited 98 participants aged 70 years or older with a Harris Hip Score less than 60 awaiting elective primary total hip replacement. Participants were recruited at three hospitals in Norway between 2019 and 2022. Participants were randomly assigned to prehabilitation or usual care. The prehabilitation group received a tailored exercise program for 6–12 weeks in addition to patient education. Gait speed, the primary outcome, was measured by the 40 m Fast-Paced Walk Test. Secondary outcomes included performance-based tests (Chair Stand Test, Timed Up & Go Test, 6-Minute Walk Test, Stair Climb Test) and patient-reported outcomes (Hip Disability and Osteoarthritis Outcome Score (HOOS) and EQ-5D). Outcomes were assessed at baseline, post intervention, and further 6 weeks, 3-, 6-, and 12 months post-surgery. Results For the primary outcome gait speed at the primary endpoint (3 months post-surgery), no significant between-group differences were observed. However, post-intervention (before surgery), we found a significant improvement in favor of prehabilitation for both gait speed (0.15 m/s, 95% CI 0.02–0.28) and the HOOS quality of life subscale (11.93, 95% CI 3.38–20.48). No other significant differences were found at any post-surgery follow-up for these outcomes. For other secondary outcomes, there were no between-group differences at any point of assessment. Both groups showed improvement across all outcomes 3–12 months after surgery. Conclusions The AktivA®program, used as a prehabilitation intervention during a period of 6–12 weeks before total hip replacement did not improve gait speed or any other post-operative outcomes compared to usual care. Both groups demonstrated significant improvement in gait speed and performed well relative to Western reference values 12 months post-surgery. Thus, replacing painful hip joints through total joint replacement seems to outweigh the efficacy of prehabilitation. Trial registration ClinicalTrials.gov Identifier: NCT03602105—initial release: 06/06/2018.

• Tang, Su’an; Zhang, Changqing; Oo, Win Min; Fu, Kai; Risberg, May Arna & Bierma-Zeinstra, Sita M. [Show all 11 contributors for this article] (2025). Osteoarthritis. Nature Reviews Disease Primers. 11. doi: 10.1038/s41572-025-00594-6. Full text in Research Archive Show summary

  Osteoarthritis is a heterogeneous whole-joint disease that can cause pain and is a leading cause of disability and premature work loss. The predominant disease risk factors — obesity and joint injury — are well recognized and modifiable. A greater understanding of the complex mechanisms, including inflammatory, metabolic and post-traumatic processes, that can lead to disease and of the pathophysiology of pain is helping to delineate mechanistic targets. Currently, management is primarily focused on alleviating the main symptoms of pain and obstructed function through lifestyle interventions such as self-management programmes, education, physical activity, exercise and weight management. However, lack of adherence to known effective osteoarthritis therapeutic strategies also contributes to the high global disease burden. For those who have persistent symptoms that are compromising quality of life and have not responded adequately to core treatments, joint replacement is an option to consider. The burden imparted by the disease causes a substantial impact on individuals affected in terms of quality of life. For society, this disease is a substantial driver of increased health-care costs and underemployment. This Primer highlights advances and controversies in osteoarthritis, drawing key insights from the current evidence base.

• Urhausen, Anouk; Grindem, Hege; Engebretsen, Lars; Silbernagel, Karin Grävare; Axe, Michael J. & Snyder-Mackler, Lynn [Show all 7 contributors for this article] (2024). The Delaware-Oslo ACL Cohort treatment algorithm yields superior outcomes to usual care 9-12 years after anterior cruciate ligament reconstruction. Knee Surgery, Sports Traumatology, Arthroscopy. ISSN 0942-2056. 32(2), p. 214–222. doi: 10.1002/ksa.12039. Full text in Research Archive
• Aga, Cathrine; Trøan, Ingrid; Heir, Stig; Risberg, May Arna; Tariq, Rana & Johansen, Steinar [Show all 8 contributors for this article] (2024). No difference in osteoarthritis, but less graft failures after 5 years, comparing anatomic double-bundle to anatomic single-bundle ACL reconstruction. Knee Surgery, Sports Traumatology, Arthroscopy. ISSN 0942-2056. doi: 10.1002/ksa.12528. Full text in Research Archive Show summary

  Purpose: The purpose of this study was to compare the incidence of knee osteoarthritis (OA) between the anatomic single-bundle (SB) and anatomic double-bundle (DB) anterior cruciate ligament (ACL) reconstruction technique after 5-year follow-up (FU). Secondary objectives were to compare patient-reported outcome measures (PROMs), clinical examination, activity level, functional tests and graft failures between the two groups. Methods: The study was a secondary analysis after 5-year FU of a randomized controlled trial (RCT) (Clinical Trials NCT01033188). One hundred and twenty patients between 18 and 40 years were randomized to either anatomic SB or anatomic DB reconstruction. The Kellgren–Lawrence (KL) classification grade ≥2 and the Osteoarthritis Research Society International (OARSI) atlas criteria score ≥2 were used for defining OA. Additionally, PROMs were obtained and clinical examinations of the knees were performed. Finally, the number of patients experiencing graft failure in each group was recorded. Results: Radiographic imaging was performed in 39 patients in the SB group and in 37 patients in the DB group. Four patients (10%) in the SB group and two (5%) in the DB group developed osteoarthritis according to the KL classification (p = 0.28). Five (13%) in the SB group and three (8%) in the DB group developed osteoarthritis according to the OARSI atlas criteria (p = 0.59; difference 5.0% [95% confidence interval, CI: −0.10 to 0.20]). There were no significant differences in the PROMs, clinical examinations, activity levels, or functional tests when comparing the two groups. Of initially 62 SB patients, 14 (23%) experienced graft failure compared to 4 (7%) of the 58 DB patients (p = 0.015; difference 0.016 [95% CI: 0.03–0.29]). Conclusion: At 5-year FU, there were no significant differences in the incidence of OA, PROMS, or other clinical findings comparing the anatomic DB to anatomic SB ACL reconstructed patients. There were fewer graft failures among patients treated with anatomic DB ACL reconstruction.

• Jacobsen, Julie S.; O'Brien, Michael J.M.; Christensen, Jeanette Reffstrup; Risberg, May Arna; Milne, Lachlan & Balakumar, Jitendra [Show all 9 contributors for this article] (2024). Rehabilitation following periacetabular osteotomy for acetabular dysplasia: A qualitative interview study exploring challenges, hopes and expectations among patients in Denmark and Australia. International Journal of Orthopaedic and Trauma Nursing. ISSN 1878-1241. 54, p. 1–8. doi: 10.1016/j.ijotn.2024.101116. Full text in Research Archive
• Berg, Bjørnar; Roos, Ewa M.; Englund, Martin Trøan; Kise, Nina Jullum; Engebretsen, Lars & Eftang, Cathrine Nørstad [Show all 7 contributors for this article] (2024). Arthroscopic partial meniscectomy versus exercise therapy for degenerative meniscal tears: 10-year follow-up of the OMEX randomised controlled trial. British Journal of Sports Medicine. ISSN 0306-3674. doi: 10.1136/bjsports-2024-108644. Full text in Research Archive Show summary

  Objectives: To evaluate radiographic knee osteoarthritis (OA) progression, development of knee OA, patient-reported outcomes, and knee muscle strength at 10-year follow-up after arthroscopic partial meniscectomy (APM) or exercise therapy for degenerative meniscal tears. Methods: Randomised controlled trial including 140 participants, with a degenerative meniscal tear, and no or minimal radiographic OA changes. Participants were randomised to either APM or 12 weeks of exercise therapy (1:1 ratio). The primary outcome was knee OA progression assessed by the Osteoarthritis Research Society International (OARSI) atlas sum score (sum of medial and lateral compartment joint space narrowing and osteophyte score). Secondary outcomes included incidence of radiographic and symptomatic knee OA, patient-reported pain and knee function, and isokinetic knee muscle strength. Results: The adjusted mean difference in change in the OARSI sum score was 0.39 (95% CI -0.19 to 0.97), with more progression in the APM group. The incidence of radiographic knee OA was 23% in the APM group and 20% in the exercise group (adjusted risk difference 3% [95% CI -13% to 19%]). No clinically relevant differences were found in patient-reported outcomes or isokinetic knee muscle strength. Conclusion: No essential differences in radiographic knee OA progression and comparable rates of knee OA development were observed 10 years following APM and exercise therapy for degenerative meniscal tears. Both treatments were associated with improved patient-reported pain and knee function.

• Whittaker, Jackie L.; Kalsoum, Raneem; Bilzon, James Lee John; Conaghan, Philip G.; Crossley, Kay & Dodge, George R. [Show all 21 contributors for this article] (2024). Toward designing human intervention studies to prevent osteoarthritis after knee injury: A report from an interdisciplinary OARSI 2023 workshop. Osteoarthritis and Cartilage Open. 6(2). doi: 10.1016/j.ocarto.2024.100449. Full text in Research Archive Show summary

  Objective: The global impact of osteoarthritis is growing. Currently no disease modifying osteoarthritis drugs/therapies exist, increasing the need for preventative strategies. Knee injuries have a high prevalence, distinct onset, and strong independent association with post-traumatic osteoarthritis (PTOA). Numerous groups are embarking upon research that will culminate in clinical trials to assess the effect of interventions to prevent knee PTOA despite challenges and lack of consensus about trial design in this population. Our objectives were to improve awareness of knee PTOA prevention trial design and discuss state-of-the art methods to address the unique opportunities and challenges of these studies. Design: An international interdisciplinary group developed a workshop, hosted at the 2023 Osteoarthritis Research Society International Congress. Here we summarize the workshop content and outputs, with the goal of moving the field of PTOA prevention trial design forward. Results: Workshop highlights included discussions about target population (considering risk, homogeneity, and possibility of modifying osteoarthritis outcome); target treatment (considering delivery, timing, feasibility and effectiveness); comparators (usual care, placebo), and primary symptomatic outcomes considering surrogates and the importance of knee function and symptoms other than pain to this population. Conclusions: Opportunities to test multimodal PTOA prevention interventions across preclinical models and clinical trials exist. As improving symptomatic outcomes aligns with patient and regulator priorities, co-primary symptomatic (single or aggregate/multidimensional outcome considering function and symptoms beyond pain) and structural/physiological outcomes may be appropriate for these trials. To ensure PTOA prevention trials are relevant and acceptable to all stakeholders, future research should address critical knowledge gaps and challenges.

• Urhausen, Anouk; Grindem, Hege; Ingelsrud, Lina Holm; Roos, Ewa M.; Silbernagel, Karin Grävare & Snyder-Mackler, Lynn [Show all 7 contributors for this article] (2024). Patient Acceptable Symptom State Thresholds for IKDC-SKF and KOOS at the 10-Year Follow-up After Anterior Cruciate Ligament Injury: A Study From the Delaware-Oslo ACL Cohort. Orthopaedic Journal of Sports Medicine (OJSM). 12(5). doi: 10.1177/23259671241250025. Full text in Research Archive Show summary

  Background: Clinicians need thresholds for the Patient Acceptable Symptom State (PASS) and Treatment Failure to interpret group-based patient-reported outcome measures after anterior cruciate ligament (ACL) injury. Validated thresholds that are crucial for accurately discerning patient symptom state and facilitating effective interpretation have not been determined for long-term follow-up after ACL injury. Purpose: To calculate and validate thresholds for PASS and Treatment Failure for the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF) and the Knee injury and Osteoarthritis Outcome Score (KOOS) subscales at the 10-year follow-up after ACL injury. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 163 participants with unilateral ACL injury (treated with reconstruction or rehabilitation alone) from the Delaware-Oslo ACL Cohort were included. Thresholds for PASS were calculated for IKDC-SKF and KOOS subscales using anchor-based predictive modeling and receiver operating characteristic (ROC) analysis. Too few participants had self-reported Treatment Failure to calculate thresholds for that outcome. Nonparametric bootstrapping was used to derive 95% CIs. The criterion validity of the predictive modeling and ROC-derived thresholds were assessed by comparing actual patient-reported PASS outcome with the calculated PASS outcome for each method of calculation and calculating their positive and negative predictive values with respect to the anchor questions. Results: A total of 127 (78%) participants reported satisfactory symptom state. Predictive modeling PASS thresholds (95% CIs) were 76.2 points (72.1-79.4 points) for IKDC-SKF, 85.4 points (80.9-89.2 points) for KOOS Pain, 76.5 points (67.8-84.7 points) for KOOS Symptoms, 93.8 points (90.1-96.9 points) for KOOS activities of daily living, 71.6 points (63.4-77.7 points) for KOOS Sports, and 59.0 points (53.7-63.9 points) for KOOS quality of life (QoL). Predictive modeling thresholds classified 81% to 93% of the participants as having satisfactory symptom state, whereas ROC-derived thresholds classified >50% as unsatisfied. The thresholds for IKDC-SKF, KOOS Sports, and KOOS QoL resulted in the most accurate percentages of PASS among all identified thresholds and therefore demonstrate the highest validity. Conclusion: Predictive modeling provided valid PASS thresholds for IKDC-SKF and KOOS at the 10-year follow-up after ACL injury. The thresholds for IKDC-SKF, KOOS Sports, and KOOS QoL should be used when determining satisfactory outcomes. ROC-derived thresholds result in substantial misclassification rates of the participants who reported satisfactory symptom state.

• Killingmo, Rikke Munk; Øiestad, Britt Elin; Risberg, May Arna; Maas, Esther & Grotle, Margreth (2024). Cost-effectiveness of strength exercise or aerobic exercise compared with usual care for patients with knee osteoarthritis: secondary results from a multiarm randomised controlled trial in Norway. BMJ Open. doi: 10.1136/bmjopen-2023-079704. Full text in Research Archive
• Øiestad, Britt Elin; Årøen, Asbjørn; Røtterud, Jan H; Østerås, Nina; Jarstad, Even & Grotle, Margreth [Show all 7 contributors for this article] (2023). The efficacy of strength or aerobic exercise on quality of life and knee function in patients with knee osteoarthritis. A multi-arm randomized controlled trial with 1-year follow-up. BMC Musculoskeletal Disorders. 24(1). doi: 10.1186/s12891-023-06831-x. Full text in Research Archive Show summary

  Objective: To evaluate the efficacy of strength exercise or aerobic exercise compared to usual care on knee-related quality of life (QoL) and knee function at 4 months and 1 year in individuals with knee osteoarthritis. Methods: A three-arm randomized controlled trial (RCT) compared 12 weeks of strength exercise or aerobic exercise (stationary cycling) to usual care supervised by physiotherapists in primary care. We recruited 168 participants aged 35–70 years with symptomatic knee osteoarthritis. The primary outcome was The Knee Injury and Osteoarthritis Outcome Score (KOOS) QoL at 1 year. Secondary outcomes were self-reported function, pain, and self-efficacy, muscle strength and maximal oxygen uptake (VO2max) at 4 months and 1 year. Results: There were no differences between strength exercise and usual care on KOOS QoL (6.5, 95% CI -0.9 to 14), or for aerobic exercise and usual care (5.0, 95% CI -2.7 to 12.8), at 1 year. The two exercise groups showed better quadriceps muscle strength, and VO2max at 4 months, compared to usual care. Conclusion: This trial found no statistically significant effects of two exercise programs compared to usual care on KOOS QoL at 1 year in individuals with symptomatic and radiographic knee osteoarthritis, but an underpowered sample size may explain lack of efficacy between the intervention groups and the usual care group.

• Fosdahl, Merete Aarsland; Berg, Bjørnar; Risberg, May Arna; Øiestad, Britt Elin & Holm, Inger (2023). Body Mass Index, Quality of Life and Activity Limitation Trajectories over 2 Years in Patients with Knee or Hip Osteoarthritis: A Dual Trajectory Approach Based on 4265 Patients Included in the AktivA Quality Register. Journal of Clinical Medicine. 12(22). doi: 10.3390/jcm12227094. Full text in Research Archive Show summary

  Background: Recent studies claim that weight-neutral approaches emphasizing physical activity might be as effective as weight-loss-centered approaches for improving pain and physical function in patients with knee and hip osteoarthritis. The objectives were to identify distinctive groups of individuals with similar BMI, quality of life and activity limitation trajectories over two years, to compare the overall differences between BMI trajectory groups for baseline variables and to explore the probabilities of the quality of life and activity limitation trajectory groups conditional on the BMI group. (2) Methods: Baseline data for age, gender, BMI, quality of life, activity limitations, pain, general health, knee or hip osteoarthritis and follow-up data on BMI, quality of life and activity limitations at 3, 12 and 24 months were retrieved from the “Active with osteoarthritis” (AktivA) electronic quality register. Group-based trajectory modeling was used to identify distinct trajectories for BMI, quality of life and activity limitations. (3) Results: 4265 patients were included in the study. Four distinct BMI trajectories were identified, normal weight (31%), slightly overweight (43%), overweight (20%) and obese (6%). At baseline, there were highly significant differences between all BMI groups, pain increased and age and general health decreased with higher BMI. Irrespective of weight category, minimal changes in BMI were found over the two-year follow-up period. Over 80% of the participants showed moderate-to-considerable improvements both in quality of life and activity limitations. (4) Conclusions: Almost 70% of the participants belonged to the overweight trajectories. Despite no significant weight reduction over the two years, eight in every 10 participants improved their quality of life and reduced their activity limitations after participating in the AktivA program.

• Winj, Stan; Hannink, Gerjon; Østerås, Håvard; Risberg, May Arna; Roos, Ewa M. & Hare, Kristoffer B. [Show all 12 contributors for this article] (2023). Arthroscopic partial meniscectomy vs non-surgical or sham treatment in patients with MRI-confirmed degenerative meniscus tears: a systematic review and meta-analysis with individual participant data from 605 randomised patients. Osteoarthritis and Cartilage. ISSN 1063-4584. 31(5), p. 557–566. doi: 10.1016/j.joca.2023.01.002. Full text in Research Archive Show summary

  Objective: To identify subgroups of patients with magnetic resonance imaging (MRI)-confirmed degenerative meniscus tears who may benefit from arthroscopic partial meniscectomy (APM) in comparison with non-surgical or sham treatment. Methods: Individual participant data (IPD) from four RCTs were pooled (605 patients, mean age: 55 (SD: 7.5), 52.4% female) as to investigate the effectiveness of APM in patients with MRI-confirmed degenerative meniscus tears compared to non-surgical or sham treatment. Primary outcomes were knee pain, overall knee function, and health-related quality of life, at 24 months follow-up (0–100). The IPD were analysed in a one- and two-stage meta-analyses. Identification of potential subgroups was performed by testing interaction effects of predefined patient characteristics (e.g., age, gender, mechanical symptoms) and APM for each outcome. Additionally, generalized linear mixed-model trees were used for subgroup detection. Results: The APM group showed a small improvement over the non-surgical or sham group on knee pain at 24 months follow-up (2.5 points (95% CI: 0.8–4.2) and 2.2 points (95% CI: 0.9–3.6), one- and two-stage analysis, respectively). Overall knee function and health-related quality of life did not differ between the two groups. Across all outcomes, no relevant subgroup of patients who benefitted from APM was detected. The generalized linear mixed-model trees did also not identify a subgroup. Conclusions: No relevant subgroup of patients was identified that benefitted from APM compared to non-surgical or sham treatment. Since we were not able to identify any subgroup that benefitted from APM, we recommend a restrained policy regarding meniscectomy in patients with degenerative meniscus tears.

• Arhos, Elanna K.; Pohlig, Ryan T.; Stasi, Stephanie Di; Risberg, May Arna; Snyder-Mackler, Lynn & Silbernagel, Karin Grävare (2023). Clinically Relevant Subgroups Among Athletes Who Have Ruptured Their Anterior Cruciate Ligaments: A Delaware-Oslo Cohort Study. Arthritis care & research. ISSN 2151-464X. 75(9), p. 1914–1924. doi: 10.1002/acr.25089. Full text in Research Archive Show summary

  Objective: To identify subgroups of individuals with anterior cruciate ligament (ACL) injuries based on patient characteristics, self-reported outcomes, and functional performance at baseline, and to associate subgroups with long-term outcomes after ACL rupture. Methods: A total of 293 participants (45.7% male, mean ± SD age 26.2 ± 9.4 years, days from injury 58 ± 35) were enrolled after effusion, pain, and range of motion impairments were resolved and quadriceps strength was at least 70% of the uninvolved limb. Mixture modeling was used to uncover latent subgroups without a prior group classification using probabilistic assignment. Variables include demographics, functional testing, and self-reported outcome measures. Radiographic evidence of osteoarthritis (OA; i.e., Kellgren/Lawrence grade of ≥1) in the involved knee at 5 years after injury was the primary outcome of interest. Chi-square tests assessed differences in the presence of radiographic OA in the involved knee between subgroups at 5 years after ACL rupture. Secondary outcomes of interest included radiographic OA in the uninvolved knee, return to preinjury sport by 2 years, operative status, and clinical OA (classified using Luyten et al criteria) at 5 years. Results: Four distinct subgroups exist after ACL rupture (younger good self-report, younger poor self-report, older poor self-report, older good self-report) with 30%, 31%, 47%, and 53%, respectively, having involved knee OA. The percentage of radiographic OA was not significantly different between the groups (P = 0.059). Conclusion: The prevalence of OA in all subgroups is highly concerning. These results suggest there are unique subgroupings of individuals that may guide treatment after ACL rupture and reconstruction by providing support for developing a patient-centered approach.

• Holden, Melanie; Hattle, Miriam; Runhaar, Jos; Riley, Richard D; Healey, Emma L. & Quicke, Jonathan [Show all 50 contributors for this article] (2023). Moderators of the effect of therapeutic exercise for knee and hip osteoarthritis: a systematic review and individual participant data meta-analysis. The Lancet Rheumatology. 5(7). doi: 10.1016/S2665-9913(23)00122-4. Full text in Research Archive Show summary

  Background Many international clinical guidelines recommend therapeutic exercise as a core treatment for knee and hip osteoarthritis. We aimed to identify individual patient-level moderators of the effect of therapeutic exercise for reducing pain and improving physical function in people with knee osteoarthritis, hip osteoarthritis, or both. Methods We did a systematic review and individual participant data (IPD) meta-analysis of randomised controlled trials comparing therapeutic exercise with non-exercise controls in people with knee osteoathritis, hip osteoarthritis, or both. We searched ten databases from March 1, 2012, to Feb 25, 2019, for randomised controlled trials comparing the effects of exercise with non-exercise or other exercise controls on pain and physical function outcomes among people with knee osteoarthritis, hip osteoarthritis, or both. IPD were requested from leads of all eligible randomised controlled trials. 12 potential moderators of interest were explored to ascertain whether they were associated with short-term (12 weeks), medium-term (6 months), and long-term (12 months) effects of exercise on self-reported pain and physical function, in comparison with non-exercise controls. Overall intervention effects were also summarised. This study is prospectively registered on PROSPERO (CRD42017054049). Findings Of 91 eligible randomised controlled trials that compared exercise with non-exercise controls, IPD from 31 randomised controlled trials (n=4241 participants) were included in the meta-analysis. Randomised controlled trials included participants with knee osteoarthritis (18 [58%] of 31 trials), hip osteoarthritis (six [19%]), or both (seven [23%]) and tested heterogeneous exercise interventions versus heterogeneous non-exercise controls, with variable risk of bias. Summary meta-analysis results showed that, on average, compared with non-exercise controls, therapeutic exercise reduced pain on a standardised 0–100 scale (with 100 corresponding to worst pain), with a difference of –6·36 points (95% CI –8·45 to –4·27, borrowing of strength [BoS] 10·3%, between-study variance [τ2] 21·6) in the short term, –3·77 points (–5·97 to –1·57, BoS 30·0%, τ2 14·4) in the medium term, and –3·43 points (–5·18 to –1·69, BoS 31·7%, τ2 4·5) in the long term. Therapeutic exercise also improved physical function on a standardised 0–100 scale (with 100 corresponding to worst physical function), with a difference of –4·46 points in the short term (95% CI –5·95 to –2·98, BoS 10·5%, τ2 10·1), –2·71 points in the medium term (–4·63 to –0·78, BoS 33·6%, τ2 11·9), and –3·39 points in the long term (–4·97 to –1·81, BoS 34·1%, τ2 6·4). Baseline pain and physical function moderated the effect of exercise on pain and physical function outcomes. Those with higher self-reported pain and physical function scores at baseline (ie, poorer physical function) generally benefited more than those with lower self-reported pain and physical function scores at baseline, with the evidence most certain in the short term (12 weeks). Interpretation There was evidence of a small, positive overall effect of therapeutic exercise on pain and physical function compared with non-exercise controls. However, this effect is of questionable clinical importance, particularly in the medium and long term. As individuals with higher pain severity and poorer physical function at baseline benefited more than those with lower pain severity and better physical function at baseline, targeting individuals with higher levels of osteoarthritis-related pain and disability for therapeutic exercise might be of merit.

• Kobayashi, Sarah; Allen, Kelli; Bennell, Kim; Bowden, Jocelyn L.; Briggs, Andrew M. & Burgess, Annette [Show all 13 contributors for this article] (2022). A Framework to Guide the Development of Health Care Professional Education and Training in Best Evidence Osteoarthritis Care. Clinics in Geriatric Medicine. ISSN 0749-0690. 38(2), p. 361–384. doi: 10.1016/j.cger.2021.11.008. Full text in Research Archive
• Berg, Bjørnar; Urhausen, Anouk; Øiestad, Britt Elin; Whittaker, Jackie L.; Culvenor, Adam G. & Roos, Ewa M. [Show all 9 contributors for this article] (2022). What tests should be used to assess functional performance in youth and young adults following anterior cruciate ligament or meniscal injury? A systematic review of measurement properties for the OPTIKNEE consensus. British Journal of Sports Medicine. ISSN 0306-3674. doi: 10.1136/bjsports-2022-105510. Full text in Research Archive
• Urhausen, Anouk; Berg, Bjørnar; Øiestad, Britt Elin; Whittaker, Jackie L.; Culvenor, Adam G. & Crossley, Kay M. [Show all 8 contributors for this article] (2022). Measurement properties for muscle strength tests following anterior cruciate ligament and/or meniscus injury: What tests to use and where do we need to go? A systematic review with meta-analyses for the OPTIKNEE consensus. British Journal of Sports Medicine. ISSN 0306-3674. 56(24), p. 1422–1431. doi: 10.1136/bjsports-2022-105498. Full text in Research Archive Show summary

  Objectives: Critically appraise and summarise the measurement properties of knee muscle strength tests after anterior cruciate ligament (ACL) and/or meniscus injury using the COnsensus-based Standards for the selection of health Measurement INstruments Risk of Bias checklist. Design: Systematic review with meta-analyses. The modified Grading of Recommendations Assessment, Development and Evaluation-guided assessment of evidence quality. Data sources: Medline, Embase, CINAHL and SPORTSDiscus searched from inception to 5 May 2022. Eligibility criteria for selecting studies: Studies evaluating knee extensor or flexor strength test reliability, measurement error, validity, responsiveness or interpretability in individuals with ACL and/or meniscus injuries with a mean injury age of ≤30 years. Results: Thirty-six studies were included involving 31 different muscle strength tests (mode and equipment) in individuals following an ACL injury and/or an isolated meniscus injury. Strength tests were assessed for reliability (n=8), measurement error (n=7), construct validity (n=27) and criterion validity (n=7). Isokinetic concentric extensor and flexor strength tests were the best rated with sufficient intrarater reliability (very low evidence quality) and construct validity (moderate evidence quality). Isotonic extensor and flexor strength tests showed sufficient criterion validity, while isometric extensor strength tests had insufficient construct and criterion validity (high evidence quality). Conclusion: Knee extensor and flexor strength tests of individuals with ACL and/or meniscus injury lack evidence supporting their measurement properties. There is an urgent need for high-quality studies on these measurement properties. Until then, isokinetic concentric strength tests are most recommended, with isotonic strength tests a good alternative.

• Pedersen, Marie; Grindem, Hege; Berg, Bjørnar; Engebretsen, Lars; Axe, Michael J. & Snyder-Mackler, Lynn [Show all 7 contributors for this article] (2022). Four Distinct 5-Year Trajectories of Knee Function Emerge in Patients Who Followed the Delaware-Oslo ACL Cohort Treatment Algorithm. American Journal of Sports Medicine. ISSN 0363-5465. 50(11), p. 2944–2952. doi: 10.1177/03635465221116313. Full text in Research Archive Show summary

  Background: Impairments and dysfunction vary considerably after anterior cruciate ligament (ACL) injury, and distinct subgroups may exist. Purpose: (1) To identify subgroups of patients with ACL injury who share common trajectories of patient-reported knee function from initial presentation to 5 years after a treatment algorithm where they chose either ACL reconstruction (ACLR) plus rehabilitation or rehabilitation alone. (2) To assess associations with trajectory affiliation. Study Design: Cohort study; Level of evidence, 3. Methods: We included 276 patients with a acute first-time complete unilateral ACL injury. All patients underwent a 5-week neuromuscular and strength training program before a shared decision-making process about treatment. Within their latest attended follow-up, 62% of patients had undergone early ACLR (<6 months after the 5-week program), 11% delayed ACLR (>6 months after the 5-week program), and 27% progressive rehabilitation alone. Patients completed the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF) at inclusion, after the 5-week program, and at 6 months, 1 year, 2 years, and 5 years after ACLR or completion of the 5-week program (patients treated with rehabilitation alone). We used group-based trajectory modeling to identify trajectories of IKDC-SKF and multinomial logistic regression to assess associations with trajectory affiliation. Results: Four distinct trajectories of IKDC-SKF were identified: Low (n = 22; 8.0% of the cohort), Moderate (n = 142; 51.4%), High (n = 105; 38.0%), and High Before Declining (n = 7; 2.5%). The High trajectory had higher scores at inclusion than the Moderate trajectory, but both improved considerably within 1 year and had thereafter stable high scores. The High Before Declining trajectory also started relatively high and improved considerably within 1 year but experienced a large deterioration between 2 and 5 years. The Low trajectory started low and had minimal improvement. New knee injuries were important characteristics of the High Before Declining trajectory, concomitant meniscal injuries were significantly associated with following the Low (vs Moderate) trajectory, and early/preoperative quadriceps strength and hop symmetry (measured at inclusion) were significantly associated with following the High (vs Moderate) trajectory. Conclusion: We identified 4 distinct 5-year trajectories of patient-reported knee function, indicating 4 subgroups of patients with ACL injury. Importantly, 88% of the patients who followed our treatment algorithm followed the Moderate and High trajectories characterized by good improvement and high scores. Due to eligibility criteria and procedures in our cohort, we can only generalize our model to athletes without major concomitant injuries who follow a similar treatment algorithm. Concomitant meniscal injuries and new knee injuries were important factors in the unfavorable Low and High Before Declining trajectories. These associations were exploratory but support the trajectories’ validity. Our findings can contribute to patient education about prognosis and underpin the importance of continued secondary injury prevention.

• Whittaker, Jackie L.; Culvenor, Adam G.; Juhl, Carsten Bogh; Berg, Bjørnar; Bricca, Alessio & Filbay, Stephanie Rose [Show all 38 contributors for this article] (2022). OPTIKNEE 2022: consensus recommendations to optimise knee health after traumatic knee injury to prevent osteoarthritis. British Journal of Sports Medicine. ISSN 0306-3674. 56(24), p. 1393–1405. doi: 10.1136/bjsports-2022-106299. Full text in Research Archive
• Johnson, Jessica L.; Boulton, Aaron J.; Spindler, Kurt P.; Huston, Laura J.; Spalding, Tim & Asplin, Laura [Show all 8 contributors for this article] (2022). Creating Crosswalks for Knee Outcomes After ACL Reconstruction Between the KOOS and the IKDC-SKF. Journal of Bone and Joint Surgery. American volume. ISSN 0021-9355. 104(8), p. 723–731. doi: 10.2106/JBJS.20.02233. Full text in Research Archive Show summary

  Background: Anterior cruciate ligament (ACL) registries do not all use the same patient-reported outcome measures, limiting comparisons and preventing pooling of data for meta-analysis. Our objective was to create a statistical crosswalk to convert cohort and registry mean Knee Injury and Osteoarthritis Outcome Scores (KOOS) to International Knee Documentation Committee-Subjective Knee Form (IKDC-SKF) scores and vice versa to allow these comparisons. Methods: Data from 3 ACL registries were pooled (n = 14,412) and were separated into a training data set (70% of the sample) or a validation data set (30% of the sample). The KOOS and the IKDC-SKF scores were available prior to the operation and at 1, 2, and 5 or 6 years postoperatively. We used equipercentile equating methods to create crosswalks in the training data set and examined accuracy in the validation data set as well as bootstrapping analyses to assess the impact of sample size on accuracy. Results: Preliminary analyses suggested that crosswalks could be attempted: large correlations between scores on the 2 measures (r = 0.84 to 0.94), unidimensionality of scores, and subpopulation invariance were deemed sufficient. When comparing actual scores with crosswalked scores in the validation data set, negligible bias was observed at the group level; however, individual score deviations were variable. The crosswalks are successful for the group level only. Conclusions: Our crosswalks successfully convert between the KOOS and the IKDC-SKF scores to allow for a group-level comparison of registry and other cohort data.

• Berg, Bjørnar; Roos, Ewa M.; Kise, Nina Jullum; Engebretsen, Lars; Holm, Inger & Risberg, May Arna (2021). Muscle strength and osteoarthritis progression after surgery or exercise for degenerative meniscal tears: Secondary analyses of a randomized trial. Arthritis care & research. ISSN 2151-464X. 74(1). doi: 10.1002/acr.24736. Full text in Research Archive Show summary

  Objective: To evaluate muscle strength changes following partial meniscectomy or exercise therapy for degenerative meniscal tears and the relationship between baseline muscle strength and osteoarthritis progression. Methods: Secondary analysis of a randomized trial (n=140 participants). Isokinetic quadriceps and hamstrings strength (peak torque [N·m/kg] and total work [J/kg]) were assessed at baseline, three-, 12-month, and five-year follow-up. Between-group differences were analyzed using intention-to-treat linear mixed models. The relationship between baseline muscle strength and osteoarthritis progression (Kellgren and Lawrence, ≥1 grade increase) were assessed using logistic regression models. Results: We found statistically significant between-group differences favoring exercise therapy at three months (quadriceps: -0.30 N·m/kg, 95% CI -0.40, -0.20; hamstrings: -0.10 N·m/kg, 95% CI -0.15, -0.04) and 12 months (quadriceps: -0.13 N·m/kg, 95% CI -0.23, -0.03; hamstrings: -0.08 N·m/kg, 95% CI -0.14, -0.03). At five years, between-group differences were -0.10 N·m/kg (95% CI -0.21 to 0.01) for quadriceps and -0.07 N·m/kg (95% CI -0.13 to -0.01) for hamstrings. Quadriceps muscle weakness at baseline was associated with knee osteoarthritis progression over five years: adjusted odds ratio of 1.40 for every 0.2 N·m/kg decrease (95% CI 1.15 to 1.71). The adjusted odds ratio for hamstrings was 1.14 (95% CI 0.97-1.35) for every 0.1 N·m/kg decrease. Conclusion: Exercise therapy was effective in improving muscle strength at three and 12-month follow-up compared to partial meniscectomy, but the effect was attenuated at five years. Quadriceps muscle weakness at baseline was associated with higher odds of osteoarthritis progression over five years.

• Berg, Bjørnar; Roos, Ewa M.; Kise, Nina Jullum; Engebretsen, Lars; Holm, Inger & Risberg, May Arna (2021). On a Trajectory for Success—9 in Every 10 People With a Degenerative Meniscus Tear Have Improved Knee Function in the 2 Years After Treatment: A Secondary Exploratory Analysis of a Randomized Controlled Trial. Journal of Orthopaedic and Sports Physical Therapy. ISSN 0190-6011. 51(6), p. 289–297. doi: 10.2519/jospt.2021.10025. Full text in Research Archive Show summary

  Objective: To identify trajectories of patient-reported knee function over five years in patients with degenerative meniscal tears, and to explore whether baseline characteristics were associated with trajectories of sport and recreational function. Design: Prospective cohort study. Methods: We conducted a secondary exploratory analysis of the randomized controlled Odense-Oslo Meniscectomy versus Exercise (OMEX) trial. Patient-reported knee function was assessed with the Knee injury and Osteoarthritis Outcome Score (KOOS) at baseline, three, 12, and 24 months, and five years. We used group-based trajectory modeling to identify subgroups who followed distinctive patterns of change. Multinomial logistic regression was used to examine the association of demographic, knee function- and disease-related factors with KOOS sport and recreational function (sport/rec) trajectories. Results: We analyzed data from 140 participants. We identified three trajectories for all KOOS subscales: (i) low, minimal improvement (10%-12% of the participants), (ii) moderate, gradual improvement (20%-36%), and (iii) high, early improvement (53%-70%). Baseline prognostic factors for deteriorating function in sport and recreational activities were higher BMI, poorer mental health, greater knee pain, lower perceived knee function, poorer quadriceps and hamstrings muscle strength, poorer functional performance, more meniscal extrusion, and having radiographic signs of knee osteoarthritis. Conclusion: We found three distinct trajectories of patient-reported knee function over five years: (i) low, minimal improvement, (ii) moderate, gradual improvement, (iii) high, early improvement. Nine in every 10 participants improved at least gradually over two years after diagnosis of a degenerative meniscus tear.

• Pedersen, Marie; Grindem, Hege; Johnson, Jessica L.; Engebretsen, Lars; Axe, Michael J. & Snyder-Mackler, Lynn [Show all 7 contributors for this article] (2021). Clinical, Functional, and Physical Activity Outcomes 5 Years Following the Treatment Algorithm of the Delaware-Oslo ACL Cohort Study. Journal of Bone and Joint Surgery. American volume. ISSN 0021-9355. 103(16), p. 1473–1481. doi: 10.2106/JBJS.20.01731. Full text in Research Archive Show summary

  Background: Anterior cruciate ligament (ACL) injuries can be treated with or without ACL reconstruction (ACLR), and more high-quality studies evaluating outcomes after the different treatment courses are needed. The purpose of the present study was to describe and compare 5-year clinical, functional, and physical activity outcomes for patients who followed our decision-making and treatment algorithm and chose (1) early ACLR with preoperative and postoperative rehabilitation, (2) delayed ACLR with preoperative and postoperative rehabilitation, or (3) progressive rehabilitation alone. Early ACLR was defined as that performed ≤6 months after the preoperative rehabilitation program, and late ACLR was defined as that performed >6 months after the preoperative rehabilitation program. Methods: We included 276 patients from a prospective cohort study. The patients had been active in jumping, pivoting, and cutting sports before the injury and sustained a unilateral ACL injury without substantial concomitant knee injuries. The patients chose their treatment through a shared decision-making process. At 5 years, we assessed the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF), Knee injury and Osteoarthritis Outcome Score (KOOS), Marx Activity Rating Scale, sports participation, quadriceps muscle strength, single-legged hop performance, and new ipsilateral and contralateral knee injuries. Results: The 5-year follow-up rate was 80%. At 5 years, 64% of the patients had undergone early ACLR, 11% had undergone delayed ACLR, and 25% had had progressive rehabilitation alone. Understandably, the choices that participants made differed by age, concomitant injuries, symptoms, and predominantly level-I versus level-II preinjury activity level. There were no significant differences in any clinical, functional, or physical activity outcomes among the treatment groups. Across treatment groups, 95% to 100% of patients were still active in some kind of sports and 65% to 88% had IKDC-SKF and KOOS scores above the threshold for a patient acceptable symptom state. Conclusions: Patients with ACL injury who were active in jumping, pivoting, and cutting sports prior to injury; who had no substantial concomitant knee injuries; and who followed our decision-making and treatment algorithm had good 5-year knee function and high sport participation rates. Three of 4 patients had undergone ACLR within 5 years. There were no significant differences in any outcomes among patients treated with early ACLR, delayed ACLR, or progressive rehabilitation alone.

• Pedersen, Marie; Grindem, Hege; Berg, Bjørnar; Gunderson, Ragnhild; Engebretsen, Lars & Axe, Michael J. [Show all 8 contributors for this article] (2021). Low Rates of Radiographic Knee Osteoarthritis 5 Years After ACL Reconstruction or Rehabilitation Alone: The Delaware-Oslo ACL Cohort Study. Orthopaedic Journal of Sports Medicine (OJSM). 9(8), p. 1–10. doi: 10.1177/23259671211027530. Full text in Research Archive Show summary

  Background: Patients and clinicians often struggle to choose the optimal management strategy for posttraumatic knee osteoarthritis (OA) after an anterior cruciate ligament (ACL) injury. An evaluation of radiographic outcomes after a decision-making and treatment algorithm applicable in clinical practice can help to inform future recommendations and treatment choices. Purpose: To describe and compare 5-year radiographic outcomes and knee pain in individuals who had gone through our decision-making and treatment algorithm and chosen (1) early (<6months) ACL reconstruction (ACLR) with pre- and postoperative rehabilitation, (2) delayed (>6 months) ACLR with pre- and postoperative rehabilitation, or (3) progressive rehabilitation alone. Study Design: Cohort study; Level of evidence, 2. Methods: We included 276 patients with unilateral ACL injury from a prospective cohort study. Patients chose management using a shared decision-making process and treatment algorithm, and 5-year postoperative radiographs of the index and contralateral knees were assessed using the Kellgren and Lawrence (K&L) classification and minimum joint space width measurements. We defined radiographic tibiofemoral OA as K&L grade ≥2 and knee pain as a Knee injury and Osteoarthritis Outcome Score for Pain ≤72. To further explore early radiographic changes, we included alternative cutoffs for radiographic knee OA using K&L grade ≥2/osteophyte (definite osteophyte without joint space narrowing) and K&L grade ≥1. Results: At 5 years, 64% had undergone early ACLR; 11%, delayed ACLR; and 25%, progressive rehabilitation alone. Radiographic examination was attended by 187 patients (68%). Six percent of the cohort had radiographic tibiofemoral OA (K&L grade ≥2) in the index knee; 4%, in the contralateral knee. Using the alternative cutoffs at K&L grade ≥2/osteophyte and K&L grade ≥1, the corresponding numbers were 20% and 33% in the index knee and 18% and 29% in the contralateral knee. Six percent had a painful index knee. There were no statistically significant differences in any radiographic outcomes or knee pain among the 3 management groups. Conclusion: There were no statistically significant differences in any 5-year radiographic outcomes or knee pain among the 3 management groups. Very few of the patients who participated in our decision-making and treatment algorithm had knee OA or knee pain at 5 years.

• Moksnes, Håvard; Ardern, Clare L.; Kvist, Joanna; Engebretsen, Lars; Risberg, May Arna & Myklebust, Grethe [Show all 7 contributors for this article] (2021). Assessing implementation, limited efficacy, and acceptability of the BEAST tool: A rehabilitation and return-to-sport decision tool for nonprofessional athletes with anterior cruciate ligament reconstruction. Physical Therapy in Sport. ISSN 1466-853X. 52, p. 147–154. doi: 10.1016/j.ptsp.2021.08.011. Full text in Research Archive Show summary

  Objectives: To assess the implementation, limited efficacy, and acceptability of the BEAST (better and safer return to sport) tool – a rehabilitation and return-to-sport (RTS) decision tool after anterior cruciate ligament reconstruction (ACLR) in nonprofessional athletes. Design: Prospective cohort. Participants: 43 nonprofessional pivoting sport athletes with ACLR. Main outcome: Clinician- and athlete-experienced implementation challenges (implementation), changes in quadriceps power, side hop and triple hop performance from 6 to 8 months after ACLR (limited efficacy), athletes’ beliefs about the individual rehabilitation and RTS plans produced by the BEAST tool (acceptability). Results: The BEAST tool was developed and then implemented as planned for 39/43 (91%) athletes. Hop and quadriceps power performance improved significantly, with the largest improvement in involved quadriceps power (standardised response mean 1.4, 95% CI:1.1–1.8). Athletes believed the rehabilitation and RTS plan would facilitate RTS (8.2 [SD: 2.0]) and reduce injury risk (8.3 [SD: 1.2]; 0 = not likely at all, 10 = extremely likely). Conclusion: The BEAST tool was implemented with few challenges and adjustments were rarely necessary. Athletes had large improvements in quadriceps power and hop performance on the involved leg. Athletes believed that the individual rehabilitation and RTS plans produced by the tool would facilitate RTS and reduce injury risk.

• Reiman, Michael P.; Agricola, Rintje; Kemp, Joanne L.; Heerey, Joshua J.; Weir, Adam & Klij, Pim van [Show all 43 contributors for this article] (2020). Consensus recommendations on the classification, definition and diagnostic criteria of hip-related pain in young and middle-aged active adults from the International Hip-related Pain Research Network, Zurich 2018. British Journal of Sports Medicine. ISSN 0306-3674. 54(11), p. 631–641. doi: 10.1136/bjsports-2019-101453. Full text in Research Archive Show summary

  There is no agreement on how to classify, define or diagnose hip-related pain—a common cause of hip and groin pain in young and middle-aged active adults. This complicates the work of clinicians and researchers. The International Hip-related Pain Research Network consensus group met in November 2018 in Zurich aiming to make recommendations on how to classify, define and diagnose hip disease in young and middle-aged active adults with hip-related pain as the main symptom. Prior to the meeting we performed a scoping review of electronic databases in June 2018 to determine the definition, epidemiology and diagnosis of hip conditions in young and middle-aged active adults presenting with hip-related pain. We developed and presented evidence-based statements for these to a panel of 37 experts for discussion and consensus agreement. Both non-musculoskeletal and serious hip pathological conditions (eg, tumours, infections, stress fractures, slipped capital femoral epiphysis), as well as competing musculoskeletal conditions (eg, lumbar spine) should be excluded when diagnosing hip-related pain in young and middle-aged active adults. The most common hip conditions in young and middle-aged active adults presenting with hip-related pain are: (1) femoroacetabular impingement (FAI) syndrome, (2) acetabular dysplasia and/or hip instability and (3) other conditions without a distinct osseous morphology (labral, chondral and/or ligamentum teres conditions), and that these terms are used in research and clinical practice. Clinical examination and diagnostic imaging have limited diagnostic utility; a comprehensive approach is therefore essential. A negative flexion–adduction–internal rotation test helps rule out hip-related pain although its clinical utility is limited. Anteroposterior pelvis and lateral femoral head–neck radiographs are the initial diagnostic imaging of choice—advanced imaging should be performed only when requiring additional detail of bony or soft-tissue morphology (eg, for definitive diagnosis, research setting or when planning surgery). We recommend clear, detailed and consistent methodology of bony morphology outcome measures (definition, measurement and statistical reporting) in research. Future research on conditions with hip-related pain as the main symptom should include high-quality prospective studies on aetiology and prognosis. The most common hip conditions in active adults presenting with hip-related pain are: (1) FAI syndrome, (2) acetabular dysplasia and/or hip instability and (3) other conditions without distinct osseous morphology including labral, chondral and/or ligamentum teres conditions. The last category should not be confused with the incidental imaging findings of labral, chondral and/or ligamentum teres pathology in asymptomatic people. Future research should refine our current recommendations by determining the clinical utility of clinical examination and diagnostic imaging in prospective studies.

• Arhos, Elanna K.; Thoma, Louise M.; Grindem, Hege; Logerstedt, David; Risberg, May Arna & Snyder-Mackler, Lynn (2020). Association of Quadriceps Strength Symmetry and Surgical Status with Clinical Osteoarthritis 5 Years after Anterior Cruciate Ligament Rupture. Arthritis care & research. ISSN 2151-464X. 74(3), p. 386–391. doi: 10.1002/acr.24479. Full text in Research Archive Show summary

  Objective: The objective of this study was to examine the association of quadriceps strength symmetry and surgical status (ACL reconstruction or nonoperative management) with early clinical knee OA 5 years after ACL injury or reconstruction. Methods: 204/300 athletes were analyzed 5 years after ACL injury or reconstruction (ACLR). Quadriceps strength was measured and reported as a limb symmetry index. We identified participants with early clinical knee OA using criteria that two of four Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales score ≤85% (Luyten et al. 2018). We calculated odds ratios (OR) and 95% confidence intervals (CI) using logistic regression, adjusted for age, sex, meniscal injury, and BMI, to examine the associations between quadriceps strength and surgical status with clinical knee OA. Results: 21% of participants met KOOS criteria for clinical knee OA (Luyten et al. 2018). For every 1% increase in quadriceps limb symmetry index, there was 4% lower odds of clinical OA (adjusted OR 0.96, 95% CI 0.93‐0.99) at 5 years. Surgical status was not associated with clinical knee OA (adjusted OR 0.58, 95% CI 0.23, 1.50). Conclusions: More symmetrical quadriceps strength, but not surgical status, 5 years after ACL injury or reconstruction was associated with lower odds of clinical knee OA.

• Berg, Bjørnar; Roos, Ewa M.; Englund, Martin; Kise, Nina Jullum; Tiulpin, Aleksei & Saarakkala, Simo [Show all 10 contributors for this article] (2020). Development of osteoarthritis in patients with degenerative meniscal tears treated with exercise therapy or surgery: a randomized controlled trial. Osteoarthritis and Cartilage. ISSN 1063-4584. doi: 10.1016/j.joca.2020.01.020. Full text in Research Archive Show summary

  Objective: To evaluate progression of individual radiographic features 5 years following exercise therapy or arthroscopic partial meniscectomy as treatment for degenerative meniscal tear. Design: Randomized controlled trial including 140 adults, aged 35–60 years, with a magnetic resonance image verified degenerative meniscal tear, and 96% without definite radiographic knee osteoarthritis. Participants were randomized to either 12-weeks of supervised exercise therapy or arthroscopic partial meniscectomy. The primary outcome was between-group difference in progression of tibiofemoral joint space narrowing and marginal osteophytes at 5 years, assessed semi-quantitatively by the OARSI atlas. Secondary outcomes included incidence of radiographic knee osteoarthritis and symptomatic knee osteoarthritis, medial tibiofemoral fixed joint space width (quantitatively assessed), and patient-reported outcome measures. Statistical analyses were performed using a full analysis set. Per protocol and as treated analysis were also performed. Results: The risk ratios (95% CI) for progression of semi-quantitatively assessed joint space narrowing and medial and lateral osteophytes for the surgery group were 0.89 (0.55–1.44), 1.15 (0.79–1.68) and 0.77 (0.42–1.42), respectively, compared to the exercise therapy group. In secondary outcomes (full-set analysis) no statistically significant between-group differences were found. Conclusion: The study was inconclusive with respect to potential differences in progression of individual radiographic features after surgical and non-surgical treatment for degenerative meniscal tear. Further, we found no strong evidence in support of differences in development of incident radiographic knee osteoarthritis or patient-reported outcomes between exercise therapy and arthroscopic partial meniscectomy.

• Wijn, Stan R.W.; Rovers, Maroeska M.; Rongen, Jan J.; Østerås, Håvard; Risberg, May Arna & Roos, Ewa M. [Show all 11 contributors for this article] (2020). Arthroscopic meniscectomy versus non-surgical or sham treatment in patients with MRI confirmed degenerative meniscus lesions: A protocol for an individual participant data meta-analysis. BMJ Open. 10(3). doi: 10.1136/bmjopen-2019-031864. Full text in Research Archive Show summary

  Introduction Arthroscopic partial meniscectomy (APM) after degenerative meniscus tears is one of the most frequently performed surgeries in orthopaedics. Although several randomised controlled trials (RCTs) have been published that showed no clear benefit compared with sham treatment or non-surgical treatment, the incidence of APM remains high. The common perception by most orthopaedic surgeons is that there are subgroups of patients that do need APM to improve, and they argue that each study sample of the existing trials is not representative for the day-to-day patients in the clinic. Therefore, the objective of this individual participant data meta-analysis (IPDMA) is to assess whether there are subgroups of patients with degenerative meniscus lesions who benefit from APM in comparison with non-surgical or sham treatment. Methods and analysis An existing systematic review will be updated to identify all RCTs worldwide that evaluated APM compared with sham treatment or non-surgical treatment in patients with knee symptoms and degenerative meniscus tears. Time and effort will be spent in contacting principal investigators of the original trials and encourage them to collaborate in this project by sharing their trial data. All individual participant data will be validated for missing data, internal data consistency, randomisation integrity and censoring patterns. After validation, all datasets will be combined and analysed using a one-staged and two-staged approach. The RCTs’ characteristics will be used for the assessment of clinical homogeneity and generalisability of the findings. The most important outcome will be the difference between APM and control groups in knee pain, function and quality of life 2 years after the intervention. Other outcomes of interest will include the difference in adverse events and mental health. Ethics and dissemination All trial data will be anonymised before it is shared with the authors. The data will be encrypted and stored on a secure server located in the Netherlands. No major ethical concerns remain. This IPDMA will provide the evidence base to update and tailor diagnostic and treatment protocols as well as (international) guidelines for patients for whom orthopaedic surgeons consider APM. The results will be submitted for publication in a peer-reviewed journal.

• Kemp, Joanne L.; Østerås, Nina; Mathiessen, Alexander; Nordsletten, Lars; Agricola, Rintje & Waarsing, Jan H [Show all 8 contributors for this article] (2020). Relationship between cam morphology, hip symptoms, and hip osteoarthritis: the Musculoskeletal pain in Ullersaker STudy (MUST) cohort. HIP International. ISSN 1120-7000. p. 1–8. doi: 10.1177/1120700020943853. Full text in Research Archive
• Impellizzeri, Franco M.; Jones, Denise M.; Griffin, Damian; Harris-Hayes, Marcie; Thorborg, Kristian & Crossley, Kay M. [Show all 39 contributors for this article] (2020). Patient-reported outcome measures for hip-related pain: a review of the available evidence and a consensus statement from the International Hip-related Pain Research Network, Zurich 2018. British Journal of Sports Medicine. ISSN 0306-3674. doi: 10.1136/bjsports-2019-101456. Full text in Research Archive Show summary

  Hip-related pain is a well-recognised complaint among active young and middle-aged active adults. People experiencing hip-related disorders commonly report pain and reduced functional capacity, including difficulties in executing activities of daily living. Patient-reported outcome measures (PROMs) are essential to accurately examine and compare the effects of different treatments on disability in those with hip pain. In November 2018, 38 researchers and clinicians working in the field of hip-related pain met in Zurich, Switzerland for the first International Hip-related Pain Research Network meeting. Prior to the meeting, evidence summaries were developed relating to four prioritised themes. This paper discusses the available evidence and consensus process from which recommendations were made regarding the appropriate use of PROMs to assess disability in young and middle-aged active adults with hip-related pain. Our process to gain consensus had five steps: (1) systematic review of systematic reviews; (2) preliminary discussion within the working group; (3) update of the more recent high-quality systematic review and examination of the psychometric properties of PROMs according to established guidelines; (4) formulation of the recommendations considering the limitations of the PROMs derived from the examination of their quality; and (5) voting and consensus. Out of 102 articles retrieved, 6 systematic reviews were selected and assessed for quality according to AMSTAR 2 (A MeaSurement Tool to Assess systematic Reviews). Two showed moderate quality. We then updated the most recent review. The updated literature search resulted in 10 additional studies that were included in the qualitative synthesis. The recommendations based on evidence summary and PROMs limitations were presented at the consensus meeting. The group makes the following recommendations: (1) the Hip and Groin Outcome Score (HAGOS) and the International Hip Outcome Tool (iHOT) instruments (long and reduced versions) are the most appropriate PROMs to use in young and middle-aged active adults with hip-related pain; (2) more research is needed into the utility of the HAGOS and the iHOT instruments in a non-surgical treatment context; and (3) generic quality of life measures such as the EuroQoL-5 Dimension Questionnaire and the Short Form Health Survey-36 may add value for researchers and clinicians in this field. We conclude that as none of the instruments shows acceptable quality across various psychometric properties, more methods studies are needed to further evaluate the validity of these PROMS—the HAGOS and iHOT—as well as the other (currently not recommended) PROMS.

• Johnson, Jessica L; Irrgang, James J.; Risberg, May Arna & Snyder-Mackler, Lynn (2020). Comparing the Responsiveness of the Global Rating Scale With Legacy Knee Outcome Scores: A Delaware-Oslo Cohort Study. American Journal of Sports Medicine. ISSN 0363-5465. doi: 10.1177/0363546520924817. Full text in Research Archive Show summary

  Background: The selection of patient-reported outcome measures (PROMs) is essential for obtaining meaningful information to treat a patient, determine a plan of care, and make clinical decisions; however, the process of selecting PROMs for clinical care is difficult, with the need to balance these multiple factors. Variation makes it difficult to compare data across providers and studies. Hypothesis/Purpose: The purpose was to determine the responsiveness of 4 PROMs via effect size and the presence of a ceiling effect in the 5 years after anterior cruciate ligament reconstruction (ACLR). We hypothesized that the single-item Global Rating Scale (GRS) would have an effect size and ceiling effect similar to the commonly used legacy PROMs. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Of the 300 participants, 218 had ACLR, completed postoperative progressive criterion-based rehabilitation early after surgery, and were followed for 5 years. We collected data based on the GRS, the Knee Outcome Survey–Activities of Daily Living Scale (KOS-ADLS), the International Knee Documentation Committee–Subjective Knee Form (IKDC-SKF), and the KOOS (Knee injury and Osteoarthritis Outcome Score) before and after training and at 6, 12, 24, and 60 months after ACLR. Results: The IKDC-SKF had the largest effect sizes and lowest ceiling effects. The GRS had a similar size and change in both effect size and ceiling effect when compared with the longer PROMs. The GRS and IKDC-SKF had a correlation of 0.72, and the GRS had a minimal detectable change of 2.9 or 4.8, depending on methodology. Conclusion: The GRS responded similarly to the IKDC-SKF, KOS-ADLS, and KOOS and was responsive to patient change. The ease of use and patient-specific nature of the question means that it may be appropriate to use the GRS in clinical care as a consistent measure throughout the course of rehabilitation.

• Cronström, Anna; Risberg, May Arna; Englund, Martin Trøan; Tiderius, Carl Johan; Önnerfjord, Patrik & Struglics, André [Show all 10 contributors for this article] (2020). Is good muscle function a protective factor for early signs of knee osteoarthritis after anterior cruciate ligament reconstruction? The SHIELD cohort study protocol. Osteoarthritis and Cartilage Open. 2(4). doi: 10.1016/j.ocarto.2020.100102. Full text in Research Archive
• Aae, Tommy Frøseth; Karlsen, Tommy Aleksander; Bos-Haugen, Ida Kristin; Risberg, May Arna; Lian, Øystein Bjerkestrand & Brinchmann, Jan E. (2020). Evaluating plasma extracellular vesicle microRNAs as possible biomarkers for osteoarthritis. Osteoarthritis and Cartilage Open. 1(3-4). doi: 10.1016/j.ocarto.2019.100018. Full text in Research Archive
• Grindem, Hege; Engebretsen, Lars; Axe, Michael; Snyder-Mackler, Lynn & Risberg, May Arna (2020). Activity and functional readiness, not age, are the critical factors for second anterior cruciate ligament injury : the Delaware-Oslo ACL cohort study. British Journal of Sports Medicine. ISSN 0306-3674. doi: 10.1136/bjsports-2019-100623. Full text in Research Archive Show summary

  Objective: To elucidate the relationships between age, return to level I sport (RTS) within the first postoperative year, passing RTS criteria and second anterior cruciate ligament (ACL) injury. Methods: In a prospective cohort study, 213 athletes were followed for 2 years after ACL reconstruction to record second ACL injuries. Independent variables were age, passing RTS criteria and level I RTS within the first postoperative year (vs later or no RTS). We defined passing RTS criteria as ≥90 on the Knee Outcome Survey — Activities of Daily Living Scale, global rating scale of function and quadriceps strength/hop test symmetry. Results: The follow-up rate was >87% for all outcomes. In multivariable analysis, level I RTS within the first postoperative year and passing RTS criteria were highly associated with second ACL injury (level I RTS HR: 6.0 (95% CI: 1.6 to 22.6), pass RTS criteria HR: 0.08 (95% CI: 0.01 to 0.6)), while age was not (age HR: 0.96 (95% CI: 0.89 to 1.04)). Athletes <25 years had higher level I RTS rates in the first postoperative year (60.4%) than older athletes (28.0%). Of those who returned to level I sport in the first postoperative year, 38.1% of younger and 59.1% of older athletes passed RTS criteria. Conclusion: High rates of second ACL injury in young athletes may be driven by a mismatch between RTS rates and functional readiness to RTS. Passing RTS criteria was independently associated with a lower second ACL rate. Allowing more time prior to RTS, and improving rehabilitation and RTS support, may reduce second ACL injury rates in young athletes with ACL reconstruction.

• Pedersen, Marie; Johnson, Jessica L; Grindem, Hege; Magnusson, Karin; Snyder-Mackler, Lynn & Risberg, May Arna (2020). Meniscus or Cartilage Injury at the Time of Anterior Cruciate Ligament Tear Is Associated With Worse Prognosis for Patient-Reported Outcome 2 to 10 Years After Anterior Cruciate Ligament Injury: A Systematic Review. Journal of Orthopaedic and Sports Physical Therapy. ISSN 0190-6011. 50(9), p. 490–502. doi: 10.2519/jospt.2020.9451. Full text in Research Archive Show summary

  Objectives: (1) To assess prognostic factors for patient-reported outcome measures (PROMs) and physical activity 2 to 10 years after anterior cruciate ligament reconstruction (ACLR) or anterior cruciate ligament (ACL) injury, and (2) to assess differences in prognostic factors between patients treated with ACLR and with rehabilitation alone. Design: Prognosis systematic review. Literature Search: Systematic searches were performed in PubMed, Web of Science, and SPORTDiscus. Study Selection Criteria: We selected prospective cohort studies and randomized clinical trials that included adults or adolescents undergoing either ACLR or rehabilitation alone after ACL rupture. Studies had to assess the statistical association between potential prognostic factors (factors related to patient characteristics, injury, or knee symptoms/function measured at baseline or within 1 year) and outcomes (PROMs and physical activity). Data Synthesis: Our search yielded 997 references. Twenty studies met the inclusion criteria. Seven studies with low or moderate risk of bias remained for data synthesis. Results: Moderate-certainty evidence indicated that concomitant meniscus and cartilage injuries were prognostic factors for worse PROMs 2 to 10 years after ACLR. Very low–certainty evidence suggested that body mass index, smoking, and baseline PROMs were prognostic factors for worse outcome. Very low–certainty evidence suggested that female sex and a worse baseline Marx Activity Rating Scale score were prognostic factors for a worse Marx Activity Rating Scale score 2 to 10 years after ACLR. There was a lack of studies on prognostic factors after rehabilitation alone. Conclusion: Concomitant meniscus and cartilage injuries were prognostic factors for worse long-term PROMs after ACLR. The certainty was very low for other prognostic factors.

• Holm, Inger; Pripp, Are Hugo & Risberg, May Arna (2020). The Active with OsteoArthritis (AktivA) Physiotherapy Implementation Model: A Patient Education, Supervised Exercise and Self-Management Program for Patients with Mild to Moderate Osteoarthritis of the Knee or Hip Joint. A National Register Study with a Two-Year Follow-Up. Journal of Clinical Medicine. 9(10). doi: 10.3390/jcm9103112. Full text in Research Archive Show summary

  Background: Recent systematic reviews and international guidelines recommend patient education, exercises, and weight control (if overweight) as first-line treatment for patients with hip or knee osteoarthritis (OA). The Active with osteoArthritis (AktivA) program is a physiotherapy model for the implementation of these guidelines into clinical primary care practice. The purpose of the present study was to evaluate the long-term effects of and adherence to the AktivA program for patients with mild to moderate knee or hip OA. Methods: The AktivA program includes three modules: a physiotherapy certification course, a patient education and exercise program and an electronic quality register. An electronic questionnaire including questions about, pain, quality of life, physical activity, self-efficacy and satisfaction with the AktivA program are sent to the participants at inclusion and after 3, 12 and 24 months. A linear mixed model for repeated measurements was used to assess the difference between the follow-up times. Results: Until January 2020, 6245 patients were included in the register. The response rates were 98%, 86% and 63% at 3, 12 and 24 months, respectively. After participating in the AktivA program, the patients reported decreased pain and increased health-related and disease-specific quality of life at three months and the positive effect was maintained up to two years after inclusion. The proportion of patients reporting to be inactive or having a low physical activity level was reduced from 43% to 22%. After two years, more than 80% of the participants reported to use what they have learned from the AktivA program at least once a week. Conclusions: Two years after inclusion in the AktivA physiotherapy program, the patients still report reduced pain, increased quality of life and higher activity levels.

• Kemp, Joanne L.; Risberg, May Arna; Mosler, Andrea Britt; Harris-Hayes, Marcie; Serner, Andreas & Moksnes, Håvard [Show all 42 contributors for this article] (2019). Physiotherapist-led treatment for young to middle-aged active adults with hip-related pain: consensus recommendations from the International Hip-related Pain Research Network, Zurich 2018. British Journal of Sports Medicine. ISSN 0306-3674. p. 1–8. doi: 10.1136/bjsports-2019-101458. Full text in Research Archive Show summary

  The 1st International Hip-related Pain Research Network meeting discussed four prioritised themes concerning hip-related pain in young to middle-aged adults: (1) diagnosis and classification of hip-related pain; (2) patient-reported outcome measures for hip-related pain; (3) measurement of physical capacity for hip-related pain; (4) physiotherapist-led treatment for hip-related pain. Thirty-eight expert researchers and clinicians working in the field of hip-related pain attended the meeting. This manuscript relates to the theme of physiotherapist-led treatments for hip-related pain. A systematic review on the efficacy of physiotherapist-led interventions for hip-related pain (published separately) was conducted and found that strong evidence for physiotherapist-led treatments was lacking. Prior to the meeting, draft consensus recommendations for consideration in the meeting were also developed based on the systematic review. The draft consensus recommendations were presented to all of the meeting participants via email, at least 1 week prior to the meeting. At the meeting, these recommendations were discussed, revised and voted on. Six recommendations for clinical practice and five recommendations for research were included and all gained consensus. Recommendations for clinical practice were that (i) Exercise-based treatments are recommended for people with hip-related pain. (ii) Exercise-based treatment should be at least 3 months duration. (iii) Physiotherapist-led rehabilitation after hip surgery should be undertaken. (iv) Patient-reported outcome measures, measures of physical impairment and measures of psychosocial factors should be used to monitor response to treatment. (v) Physical activity (that may include sport) is recommended for people with hip-related pain. (vi) Clinicians should discuss patient expectations, use shared-decision making and provide education. Recommendations for research were (i) Reporting of exercise programmes: Exercise descriptors such as load magnitude, number of repetitions and sets, duration of whole programme, duration of contractile element of exercise, duration of one repetition, time under tension, rest between repetitions, range of motion through which the exercise is performed, and rest between exercise sessions should be reported. (ii) Research should investigate the optimal frequency, intensity, time, type, volume and progression of exercise therapy. (iii) Research should examine the effect of patient education in people with hip-related pain. (iv) Research should investigate the effect of other treatments used in people with hip-related pain (for example: manual therapy, medications, injections). (v) Research should examine the impact of comorbidities and social determinants on treatment effectiveness in people with hip-related pain. Clinicians and researchers working with young to middle-aged active adults with hip-related pain may use these consensus recommendations to guide, develop, test and implement individualised, evidence-based physiotherapist-led rehabilitation programmes.

• Ekås, Guri Ranum; Mjelde, Marit; Larmo, Arne Feilberg; Moksnes, Håvard; Grindem, Hege & Risberg, May Arna [Show all 7 contributors for this article] (2019). Knee Pathology in Young Adults After Pediatric Anterior Cruciate Ligament Injury: A Prospective Case Series of 47 Patients With a Mean 9.5-Year Follow-up. American Journal of Sports Medicine. ISSN 0363-5465. 47(7), p. 1557–1566. doi: 10.1177/0363546519837935. Full text in Research Archive Show summary

  Background: The rate of secondary knee injuries after pediatric anterior cruciate ligament (ACL) injury is uncertain, and previous studies are limited because of poor methodology. Purpose: To evaluate the incidence of new meniscal injuries since the initial diagnostic magnetic resonance imaging (MRI) of young adults who sustained a pediatric ACL injury. In addition, to evaluate meniscal and cartilage injuries in the index knee and contralateral knee injuries on MRI at final follow-up (9.5 years). Furthermore, to assess leg length and alignment based on long-leg radiographs. Study Design: Case series; Level of evidence, 4. Methods: Study population at final follow-up included 47 young adults who sustained a pediatric ACL injury before age 13 years. They were followed prospectively since the time of injury for a mean 9.5 years at final follow-up. Imaging included diagnostic MRI of the index knee and 3.0-T MRI of both knees at 1-, 2-, and 9.5-year follow-up, in addition to long-leg radiographs at final follow-up. Forty-three patients underwent active rehabilitation without ACL reconstruction initially; 4 were treated with initial ACL reconstruction. At final follow-up, 27 (57%) had undergone ACL reconstruction. Results: Fourteen patients had meniscal tears in the index knee at final follow-up (prevalence, 30%). The majority of these were in the same location as previously repaired tears (n = 9). Between diagnostic MRI and final follow-up, 16 patients had sustained new meniscal tears to a healthy meniscus (incidence, 34%). At final follow-up, meniscal injuries recorded at baseline or during follow-up were no longer visible and appeared healed in 17 patients (20 tears). MRI at final follow-up showed cartilage injuries in the index knee of 13 patients (28%) and contralateral injuries in 8 patients (meniscus, n = 2; cartilage, n = 5; subchondral fracture, n = 1). Two patients had a leg-length difference >15 mm, and 3 had side-to-side difference in knee alignment >5°. Conclusion: The incidence of new meniscal tears after pediatric ACL injury was 34% during a mean follow-up period of 9.5 years. At final follow-up, 27 patients (57%) had normal menisci, and none had developed knee osteoarthritis. Primary active rehabilitation, close follow-up, and delayed surgery if needed may be a viable and safe treatment option for some pediatric ACL injuries.

• Mosler, Andrea Britt; Kemp, Joanne; King, Matthew; Lawrenson, Peter R; Semciw, Adam & Freke, Matthew D. [Show all 40 contributors for this article] (2019). Standardised measurement of physical capacity in young and middle-aged active adults with hip-related pain: recommendations from the first International Hip-related Pain Research Network (IHiPRN) meeting, Zurich, 2018. British Journal of Sports Medicine. ISSN 0306-3674. p. 1–9. doi: 10.1136/bjsports-2019-101457. Full text in Research Archive Show summary

  Hip-related pain can significantly impact quality of life, function, work capacity, physical activity and family life. Standardised measurement methods of physical capacity of relevance to young and middle-aged active adults with hip-related pain are currently not established. The aim of this consensus paper was to provide recommendations for clinical practice and research on standardised measurement methods of physical capacity in young and middle-aged active adults with hip-related pain. Four areas of importance were identified: (1) clinical measures (range of motion, muscle strength, functional impairments), (2) laboratory-based measures (biomechanics and muscle function (muscle activity, size and adiposity)), (3) physical activity, and (4) return to sport/performance. The literature was reviewed, and a summary circulated to the working group to inform discussion at the consensus meeting. The working group developed clinical and research recommendations from the literature review, which were further discussed and modified within the working group at the consensus meeting. These recommendations were then presented to all 38 International Hip-related Pain Research Network (IHiPRN) participants for further discussion, refinement and consensus voting. Therefore, the recommendations voted on were based on a combination of current evidence and expert opinion. The consensus meeting voted on 13 recommendations, six of which were clinically orientated, and seven more research specific. We recommended that clinicians working with young and middle-aged active adults with hip-related pain assess strength using objective methods of measurement, and clinically assess performance of functional tasks, including walking and running. Physical activity should be quantified using both self-reported and objective measures, and patient expectations of recovery should be quantified prior to treatment. It was recommended that return to physical activity (including sport and occupation) be quantified, and sport-specific activities should be assessed prior to return to sport. The IHiPRN participants were uncertain regarding recommendations for range of motion assessment. Research recommendations were that the measurement properties of range of motion, strength and functional performance tests be investigated, reported and improved in both clinical and research settings. Reporting of movement-related parameters (biomechanics and muscle function) should be standardised and the relationship among movement-related parameters, symptoms, function, quality of life, and intra-articular and imaging findings should be investigated. Quantification of return to physical activity (including sport and occupational demands) is required in future research, and the return to sport continuum should be used. Future research is required to determine the best criteria for rehabilitation progression and return to physical activity following hip-related pain management.

• Thoma, Louise M.; Grindem, Hege; Logerstedt, David; Axe, Michael; Engebretsen, Lars & Risberg, May Arna [Show all 7 contributors for this article] (2019). Coper Classification Early After Anterior Cruciate Ligament Rupture Changes With Progressive Neuromuscular and Strength Training and Is Associated With 2-Year Success: The Delaware-Oslo ACL Cohort Study. American Journal of Sports Medicine. ISSN 0363-5465. 47(4), p. 807–814. doi: 10.1177/0363546519825500. Full text in Research Archive Show summary

  Background: Some athletes demonstrate excellent dynamic stability after anterior cruciate ligament (ACL) rupture and return tosport without ACL reconstruction (ACLR) (copers). Others demonstrate persistent instability despite rehabilitation (noncopers) andrequire surgical stabilization. Testing to determine coper classification can identify potential copers early after rupture. It is unclearhow coper classification changes after a brief intervention and how early classification relates to long-term outcomes.Purpose:(1) To evaluate the consistency of early coper classification (potential coper vs noncoper) before and after progressiveneuromuscular and strength training (NMST) among athletes early after acute ACL rupture and (2) to evaluate the association ofearly coper classification with 2-year success after ACL rupture.Study Design:Cohort study; Level of evidence, 2.Methods:This was a prospective analysis from the Delaware-Oslo ACL Cohort Study, composed of athletes consecutively enrolledearly after ACL rupture. Participants (n = 271) were tested and classified as potential copers or noncopers according to established cri-teria before and after a 10-session NMST program. Success 2 years after ACLR or nonoperative rehabilitation was defined as meeting orexceeding sex- and age-matched norms for knee function, no ACL graft rupture, and 1 episode of giving way within the previous year.The McNemar test evaluated changes in coper classification pre- to posttraining. Logistic regression adjusted for baseline characteristicswas used to evaluate the association of early coper classification and surgical status with 2-year success.Results:Of 300 athletes enrolled, 271 (90%) completed the posttraining data collection, and 219 (73%) returned for the 2-year fol-low-up. The coper classifications were different between time points: nearly half of those classified initially as noncopers becamepotential copers (P\.001). At the 2-year follow-up, 66% of the ACLR group and 74% of the nonoperative group were successful.Athletes who were potential copers posttraining and chose ACLR or nonoperative rehabilitation had 2.7 (95% CI, 1.3-5.6) and 2.9(95% CI, 1.2-7.2) times the odds of success, respectively, as compared with noncopers who chose ACLR.Conclusion:Coper classification improved after NMST; more athletes became potential copers. Athletes who were potential co-pers after NMST were more likely to succeed 2 years later regardless of whether they had surgery, strongly supporting the addi-tion of NMST before ACLR. Persistent noncopers fared poorly, indicating that more intensive rehabilitation may be needed.

• Holm, Inger; Risberg, May Arna; Roos, Ewa M. & Skou, Søren Thorgaard (2019). A pragmatic approach to the implementation of osteoarthritis guidelines has fewer potential barriers than recommended implementation frameworks. Journal of Orthopaedic and Sports Physical Therapy. ISSN 0190-6011. 49(1), p. 1–4. doi: 10.2519/jospt.2019.0601. Full text in Research Archive Show summary

  Translating evidence-based treatment recommendations and guidelines into feasible delivery in routine care is an essential objective to improve quality of care. Nevertheless, guidelines are underused, and many physical therapists and other professionals continue to offer low-value care modalities, providing the patients with treatment options of little to no benefit. In contrast to low-value interventions, evidence-based treatment guidelines for osteoarthritis (OA) recommend information, exercise, and weight control. The authors discuss the feasibility of a pragmatic approach to implementation of clinical guidelines that facilitates improved quality of care for management of OA

• Capin, Jacob John; Failla, Mathew; Zarzycki, Ryan; Dix, Celeste; Johnson, Jessica L & Smith, Angela H [Show all 10 contributors for this article] (2019). Superior 2-Year Functional Outcomes Among Young Female Athletes After ACL Reconstruction in 10 Return-to-Sport Training Sessions: Comparison of ACL-SPORTS Randomized Controlled Trial With Delaware-Oslo and MOON Cohorts. Orthopaedic Journal of Sports Medicine (OJSM). 7(8). doi: 10.1177/2325967119861311. Full text in Research Archive Show summary

  Background: Outcomes after anterior cruciate ligament reconstruction (ACLR) are not uniformly good and are worse among young female athletes. Developing better rehabilitation and return-to-sport training programs and evaluating their outcomes are essential. Purpose: (1) Test the effect of strength, agility, plyometric, and secondary prevention (SAPP) exercises with and without perturbation training (SAPP + PERT) on strength, hops, function, activity levels, and return-to-sport rates in young female athletes 1 and 2 years after ACLR and (2) compare 2-year functional outcomes and activity levels among young female athletes in the Anterior Cruciate Ligament Specialized Post-Operative Return-to-Sports (ACL-SPORTS) trial to homogeneous cohorts who completed criterion-based postoperative rehabilitation alone (Multicenter Orthopaedic Outcomes Network [MOON]) and in combination with extended preoperative rehabilitation (Delaware-Oslo). Study Design: Randomized controlled trial, Level of evidence, 1; and cohort study, Level of evidence, 3. Methods: A total of 40 level 1 and level 2 female athletes were enrolled after postoperative impairment resolution 3 to 9 months after primary ACLR. Participants were randomized to 10 SAPP or SAPP + PERT sessions and were tested 1 and 2 years after ACLR on quadriceps strength, hop tests, functional outcomes, and return-to-sport rates. Participants were then compared with homogeneous cohorts of young (<25 years) female athletes who completed criterion-based postoperative rehabilitation alone (MOON) and in combination with extended preoperative rehabilitation (Delaware-Oslo) on 2-year functional outcomes. Results: No significant or meaningful differences were found between SAPP and SAPP + PERT, so groups were collapsed for comparison with the other cohorts. At 2-year follow-up, ACL-SPORTS had the highest scores (P < .01) on the Marx activity rating scale (ACL-SPORTS, 13.5 ± 3.3; Delaware-Oslo, 12.5 ± 2.7; MOON, 10.6 ± 5.1); International Knee Documentation Committee Subjective Knee Evaluation Form (96 ± 7, 92 ± 9, and 84 ± 14, respectively); and Knee injury and Osteoarthritis Outcome Score (KOOS) subscales for Pain (98 ± 4, 94 ± 9, and 90 ± 10, respectively), Symptoms (94 ± 6, 90 ± 9, and 83 ± 14, respectively), Activities of Daily Living (100 ± 1, 99 ± 4, and 96 ± 7, respectively), Sports and Recreation (94 ± 8, 86 ± 15, and 82 ± 17, respectively), and Quality of Life (89 ± 14, 78 ± 18, and 76 ± 19, respectively). The Patient Acceptable Symptom State threshold on the KOOS–Sports and Recreation was achieved by 100% of the ACL-SPORTS cohort compared with 90% of Delaware-Oslo and 78% of MOON (P = .011). Conclusion: Although perturbation training provided no added benefit, 10 sessions of return-to-sport training, compared with criterion-based postoperative rehabilitation alone, yielded statistically significant and clinically meaningfully higher 2-year functional outcomes among young, high-level female athletes after ACLR.

• Lie, Marthe Mehu; Risberg, May Arna; Storheim, Kjersti; Engebretsen, Lars & Øiestad, Britt Elin (2019). What's the rate of knee osteoarthritis 10 years after anterior cruciate ligament injury? An updated systematic review. British Journal of Sports Medicine. ISSN 0306-3674. doi: 10.1136/bjsports-2018-099751. Full text in Research Archive Show summary

  This updated systematic review reports data from 2009 on the prevalence, and risk factors, for knee osteoarthritis (OA) more than 10 years after anterior cruciate ligament (ACL) tear.MethodsWe systematically searched five databases (PubMed, EMBASE, AMED, Cinahl and SPORTDiscus) for prospective and retrospective studies published after 1 August 2008. Studies were included if they investigated participants with ACL tear (isolated or in combination with medial collateral ligament and/or meniscal injuries) and reported symptomatic and/or radiographic OA at a minimum of 10 years postinjury. We used a modified version of the Downs and Black checklist for methodological quality assessment and narrative synthesis to report results. The study protocol was registered in PROSPERO.ResultsForty-one studies were included. Low methodological quality was revealed in over half of the studies. At inclusion, age ranged from 23 to 38 years, and at follow-up from 31 to 51 years. Sample sizes ranged from 18 to 780 participants. The reported radiographic OA prevalence varied between 0% and 100% >10 years after injury, regardless of follow-up time. The studies with low and high methodological quality reported a prevalence of radiographic OA between 0%–100%and 1%–80%,respectively. One study reported symptomatic knee OA for the tibiofemoral (TF) joint (35%), and one study reported symptomatic knee OA for the patellofemoral (PF) joint (15%). Meniscectomy was the only consistent risk factor determined from the data synthesis.ConclusionRadiographic knee OA varied between 0% and 100% in line with our previous systematic review from 2009. Symptomatic and radiographic knee OA was differentiated in two studies only, with a reported symptomatic OA prevalence of 35% for the TF joint and 15% for PF joint. Future cohort studies need to include measurement of symptomatic knee OA in this patient group.

• Reimer, Lisa Cecilie; Jakobsen, Stig; Mortensen, Louise; Dalgas, Ulrik; Jacobsen, Julie Sandell & Søballe, Kjeld [Show all 11 contributors for this article] (2019). Efficacy of periacetabular osteotomy followed by progressive resistance training compared to progressive resistance training as non-surgical treatment in patients with hip dysplasia (PreserveHip) - a protocol for a randomised controlled trial. BMJ Open. 9(12), p. 1–8. doi: 10.1136/bmjopen-2019-032782. Full text in Research Archive Show summary

  Introduction Periacetabular osteotomy (PAO) is an established treatment for adolescent and adult patients with hip dysplasia. However, the efficacy of PAO has not been tested against another surgical intervention or conservative treatment in a randomised controlled trial before. We suggest that progressive resistance training (PRT) could be an alternative to PAO. The primary aim of this trial is therefore to examine the efficacy of PAO followed by 4 months of usual care followed by 8 months of PRT compared to 12 months of solely PRT in patients with hip dysplasia eligible for PAO in terms of patient-reported pain measured by The Copenhagen Hip and Groin Outcome Score (HAGOS). Methods and analysis This trial is a single-blinded multicentre randomised controlled clinical trial, where patients with hip dysplasia, who are eligible for PAO, will be randomised to either PAO followed by usual care and PRT or PRT only. Primary outcome is patient-reported pain, measured on the subscale pain on the HAGOS questionnaire 12 months after initiation of PAO or PRT. The key secondary outcomes are the other subscales of the HAGOS, adverse and serious adverse events, usage of painkillers (yes/no) and type of analgesics. Based on the sample size calculation, the trial needs to include 96 patients. Ethics and dissemination The trial is approved by the Central Denmark Region Committee on Biomedical Research Ethics (Journal No 1-10-72-234-18) and by the Danish Data Protection Agency (Journal No 1-16-02-120-19). The trial is also approved by The Regional Committee for Medical and Health Research Ethics, Region South-East Norway (Ref. 2018/1603). All results from this trial will be published in international peer-reviewed scientific journals regardless of whether the results are positive, negative or inconclusive.

• Warholm, Kristian Marstrand; Råbøl, Åsmund Lindvik; Løken, Sverre Bertrand; Ludvigsen, Tom; Agricola, Rintje & Tariq, Rana [Show all 8 contributors for this article] (2019). Langtidsoppfølging (6–13 år) etter hofteartroskopi med PROMS og røntgen funn. Pasienter fra Oslo universitetssykehus, 2019: Høstmøteboken - vitenskapelig program og abstrakter. Norsk Ortopedisk Forening. ISSN 9788299427517. p. 95–95. Full text in Research Archive Show summary

  Innledning: Artroskopisk behandling av Femoroacetabular Impingement Syndrome (FAIS) har globalt hatt progressiv vekst siden starten av 90-tallet. Det eksisterer lite forskning på området med langtidsoppfølging av pasientrapporterte utfallsmål (PROMS) og radiologiske forandringer. Formålet med denne studien var å undersøke PROMS og radiologiske forandringer hos pasienter operert for FAIS mellom 2004 og 2011.

• Weldingh, Eirik; Johnsen, Marianne Bakke; Hagen, Kåre Birger; Østerås, Nina; Risberg, May Arna & Natvig, Bård [Show all 11 contributors for this article] (2019). The Maternal and Paternal Effects on Clinically and Surgically Defined Osteoarthritis. Arthritis & Rheumatology. ISSN 2326-5191. 71(11), p. 1844–1848. doi: 10.1002/art.41023. Full text in Research Archive Show summary

  Objective: It is currently unknown whether osteoarthritis (OA) is inherited mainly from the mother, father, or both. This study was undertaken to explore the effect of maternal and paternal factors on hip, knee, and hand OA in offspring. Methods: Participants from the Musculoskeletal Pain in Ullensaker Study (MUST) (69% female; mean ± SD age 64 ± 9 years) and a Norwegian OA twin study (Nor‐Twin) (56% female; 49 ± 11 years) reported whether their mother and/or father had OA. Using a recurrence risk estimation approach, we calculated whether maternal and paternal OA increased the risk of 1) surgically defined hip and knee OA (i.e., total joint replacement) and 2) clinically defined hip, knee, and hand OA (i.e., the American College of Rheumatology criteria) using logistic regression. Relative risks (RRs) with 95% confidence intervals (95% CIs) were calculated. Results: Maternal OA consistently increased the risk of offspring OA across different OA locations and severities. Having a mother with OA increased the risk of any OA in daughters (RR 1.13 [95% CI 1.02–1.25] in the MUST cohort; RR 1.44 [95% CI 1.05–1.97] in the Nor‐Twin cohort) but not (or with less certainty) in sons (RR 1.16 [95% CI 0.95–1.43] in the MUST cohort; RR 1.31 [95% CI 0.71–2.41] in the Nor‐Twin cohort). Having a father with OA was less likely to increase the risk of any OA in daughters (RR 1.00 [95% CI 0.85–1.16] in the MUST cohort; RR 1.52 [95% CI 0.94–2.46] in the Nor‐Twin cohort) and sons (RR 1.08 [95% CI 0.83–1.41] in the MUST cohort; RR 0.93 [95% CI 0.35–2.48] in the Nor‐Twin cohort). Conclusion: OA in the mother increased the risk of surgically and clinically defined hip, knee, and hand OA in offspring, particularly in daughters. Our findings imply that heredity of OA may be linked to maternal genes and/or maternal‐specific factors such as the fetal environment.

• Emery, Carolyn A.; Whittaker, Jackie L.; Mahmoudian, Armaghan; Lohmander, L. Stefan; Roos, Ewa M. & Bennell, Kim L. [Show all 26 contributors for this article] (2019). Establishing outcome measures in early knee osteoarthritis. Nature Reviews Rheumatology. ISSN 1759-4790. 15(7), p. 438–448. doi: 10.1038/s41584-019-0237-3. Full text in Research Archive Show summary

  The classification and monitoring of individuals with early knee osteoarthritis (OA) are important considerations for the design and evaluation of therapeutic interventions and require the identification of appropriate outcome measures. Potential outcome domains to assess for early OA include patient-reported outcomes (such as pain, function and quality of life), features of clinical examination (such as joint line tenderness and crepitus), objective measures of physical function, levels of physical activity, features of imaging modalities (such as of magnetic resonance imaging) and biochemical markers in body fluid. Patient characteristics such as adiposity and biomechanics of the knee could also have relevance to the assessment of early OA. Importantly, research is needed to enable the selection of outcome measures that are feasible, reliable and validated in individuals at risk of knee OA or with early knee OA. In this Perspectives article, potential outcome measures for early symptomatic knee OA are discussed, including those measures that could be of use in clinical practice and/or the research setting.

• Risberg, May Arna; Holth, Guro & Øiestad, Britt Elin (2019). Styrketreningsprogram for kneartrosepasienter: Hva er adekvat dosering for å oppnå effekt av behandling? Fysioterapeuten. ISSN 0016-3384. 9, p. 28–33. Full text in Research Archive Show summary

  Purpose: Describe types, adherence, and dosage of exercises and outcomes for a strength-training program in patients with mild to moderate knee osteoarthritis. Design: Pre-post design. Material: Fifty-two patients between 35 and 70 years with mild to moderate symptomatic knee osteoarthritis were included. Methods: A 12-week strength-training program including training diaries was implemented. The following outcome measures were used: isokinetic quadriceps muscle strength test, the Knee Osteoarthritis Outcome Score (KOOS), the Numeric rating Scale (NRS) for pain, global rating of change in function (GRC) and the self-reported questionnaire for physical activity. Results: A mean of 7.9 ±3.6 and 12.5±3.3 for neuromuscular- and strength exercises, respectively, were performed per week. Seventy-three percent of the patients completed ≥80% of the exercise sessions. There was a mean increase of 36±25% in resistance for leg extension exercise during the leg extension exercise during the 12-week program. But only 18% achieved a change above a minimal detectable change for quadriceps muscle strength. Sixty-seven percent reported a change in function (GRC) and 22% a reduction in pain (NRS). Conclusion: This 12-week strength-training program had satisfactory adherence, but the doses were probably too low to gain clinical relevant changes in quadriceps muscle strength and in patient reported outcomes.

• Svinøy, Odd-Einar; Bergland, Astrid; Risberg, May Arna; Pripp, Are Hugo & Hilde, Gunvor (2019). Better before–better after: efficacy of prehabilitation for older patients with osteoarthritis awaiting total hip replacement—a study protocol for a randomised controlled trial in South-Eastern Norway. BMJ Open. 9(12), p. 1–8. doi: 10.1136/bmjopen-2019-031626. Full text in Research Archive
• Kise, Nina Jullum; Aga, Cathrine; Engebretsen, Lars; Roos, Ewa M.; Tariq, Rana & Risberg, May Arna (2019). Complex Tears, Extrusion, and Larger Excision Are Prognostic Factors for Worse Outcomes 1 and 2 Years After Arthroscopic Partial Meniscectomy for Degenerative Meniscal Tears: A Secondary Explorative Study of the Surgically Treated Group From the Odense-Oslo Meniscectomy Versus Exercise (OMEX) Trial. American Journal of Sports Medicine. ISSN 0363-5465. 47(10), p. 2402–2411. doi: 10.1177/0363546519858602. Full text in Research Archive Show summary

  Background: Few studies have examined morphological findings from preoperative magnetic resonance imaging (MRI) and arthroscopic findings as prognostic factors for outcomes 1 and 2 years after arthroscopic partial meniscectomy (APM). Purpose/Hypothesis: The purpose was to evaluate prognostic factors of preoperative findings from MRI and arthroscopic evaluation on lower extremity performance at 1 year and patient-reported outcomes at 1 to 2 years after APM. The hypothesis was that medial compartment abnormalities would be prognostic for 1- and 2-year functional outcomes. Study Design: Cohort study; Level of evidence, 2. Methods: This secondary analysis from the OMEX (Odense-Oslo Meniscectomy Versus Exercise) trial included 40 patients treated surgically. Regression analyses with adjustments for age, sex, and body mass index explored associations between MRI findings (tear complexity and extrusion), arthroscopic findings (tear length, cartilage injury, and amount of excised meniscal tissue), and the following: lower extremity performance tests and thigh muscle strength at 1 year and the 5 Knee injury and Osteoarthritis Outcome Score (KOOS) subscales at 1 and 2 years. Results: A complex meniscal tear was a significant and clinically relevant prognostic factor for worse KOOS Symptoms subscores at 2 years (mean, 14.1 points [95% CI, 6.1-22.2]). Meniscal extrusion of at least 11%, 25%, and 20% were significant and clinically relevant prognostic factors for worse KOOS Activities of Daily Living (ADL) subscores at 1 year and worse KOOS Sports and Recreation (Sports/Rec) subscores at 1 and 2 years, respectively. Tear lengths of at least 7.0 mm, 6.7 mm, and 6.5 mm were significant and clinically relevant prognostic factors for better KOOS Symptoms subscores at 1 year and better KOOS Sports/Rec subscores at 1 and 2 years, respectively. A cartilage injury in the medial compartment was a significant and clinically relevant prognostic factor for worse KOOS ADL and Quality of Life (QoL) subscores at 2 years (mean, 10.4 and 19.4 points, respectively [95% CI, 3.4-17.4 and 7.7-31.1, respectively]). More than 20% meniscal tissue excised was a significant and clinically relevant prognostic factor for worse KOOS Pain, Symptoms, ADL, and Sports/Rec subscores at 1 and 2 years (mean, 8.9-41.5 points [95% CI, 2.2-15.5 to 21.0-62.0]) and worse KOOS QoL subscores at 2 years (mean, 25.3 points [95% CI, 13.6-37.0]). Conclusion: Complex meniscal tears, larger extrusion, cartilage injuries, and larger meniscal excision were significant and clinically relevant prognostic factors for worse outcomes 1 and 2 years after APM.

• Lien-Iversen, Teodor; Morgan, Daniel Barklin; Jensen, Carsten; Risberg, May Arna; Engebretsen, Lars & Viberg, Bjarke (2019). Does surgery reduce knee osteoarthritis, meniscal injury and subsequent complications compared with non-surgery after ACL rupture with at least 10 years follow-up? A systematic review and meta-analysis. British Journal of Sports Medicine. ISSN 0306-3674. 54(10), p. 1–8. doi: 10.1136/bjsports-2019-100765. Full text in Research Archive Show summary

  Objective: We compared long-term follow-up from surgical versus non-surgical treatment of ACL rupture regarding radiographic knee osteoarthritis (OA), secondary surgery, laxity and patient-reported outcome measures (PROMs). Design: Systematic review and meta-analysis. Data sources: Embase, MEDLINE, CINAHL and the Cochrane Library databases. Eligibility criteria for selecting studies: Studies directly comparing the minimally invasive surgical (arthroscopy or miniarthrotomy) and non-surgical treatment of ACL rupture with at least 10 years of follow-up in adult patients were included. Results: Five studies met the eligibility criteria. A meta-analysis revealed a higher risk of radiographic knee OA and a lower risk of secondary meniscal surgery for patients in the surgical group. The risk of graft rupture/secondary ACL revision and secondary ACL reconstruction was equal in the surgical and non-surgical groups. Knee laxity was lower among patients in the surgical group in four studies. No difference was found in the PROMs (ie, International Knee Documentation Committee, Tegner, Knee Injury and Osteoarthritis Outcome, and Lysholm scores). Conclusion: The risk of radiographic knee OA was higher, but the risk of secondary meniscal injury was lower 10 years after surgical treatment of ACL rupture. The risk of graft rupture/secondary ACL revision or secondary reconstruction was unrelated to treatment type. The degree of knee laxity was reduced after surgical treatment in comparison with non-surgical treatment, while PROMs were similar. However, due to the methodological challenges highlighted in this systematic review, these findings must be interpreted with caution.

• Ekås, Guri Ranum; Moksnes, Håvard; Grindem, Hege; Risberg, May Arna & Engebretsen, Lars (2019). Coping With Anterior Cruciate Ligament Injury From Childhood to Maturation: A Prospective Case Series of 44 Patients With Mean 8 Years’ Follow-up. American Journal of Sports Medicine. ISSN 0363-5465. 47(1), p. 22–30. doi: 10.1177/0363546518810750. Full text in Research Archive Show summary

  Background: There is no consensus regarding the best treatment approach for skeletally immature children with anterior cruciate ligament (ACL) injuries. High-quality studies with long-term follow-up are lacking, and evidence to support decision making is limited. Purpose: To evaluate functional and patient-reported outcome, surgical history, and complications among young adults who sustained an ACL injury before the age of 13 years and were treated with active rehabilitation and the option of delayed ACL reconstruction if needed. Study Design: Case series; Level of evidence, 4. Methods: Forty-six children aged <13 years with a total intrasubstance ACL injury were included. None of these patients had additional injuries that warranted early surgery. At final follow-up at a mean 8 years after the time of injury, 44 patients remained in the study. The same test battery was conducted at baseline, 1 and 2 years, and final follow-up at approximately 18 years of age. The test battery included functional tests (hop tests and isokinetic muscle strength tests of quadriceps and hamstrings), patient-reported outcome measures (including the Knee injury and Osteoarthritis Outcome Score and the International Knee Documentation Committee Subjective Knee Form), and clinical examination. Medical records were reviewed to assess surgical history and complications. Results: At a mean 8 years of follow-up, 24 patients (55%) had undergone ACL reconstruction, and 16 (36%) had undergone meniscal surgery. Quadriceps muscle strength symmetry was >90% for 30 patients (68%). Mean leg symmetry indexes for hop and strength tests were consistently >90%, except for the single-hop test and hamstrings muscle strength for ACL-reconstructed knees. Mean ± SD International Knee Documentation Committee scores were 86.3 ± 13.7 for the ACL-reconstructed knees and 90.6 ± 11.8 for the nonreconstructed knees. At final follow-up, forty patients (91%) remained active in sports, but 29 (66%) restricted their activity level to nonpivoting sports. Conclusion: Active rehabilitation may have a role in treatment of children with ACL injury. Approximately 50% of children may cope well, even to adulthood, without a surgical intervention. The other half may develop instability that warrants ACL reconstruction, and one-third may require meniscal surgery.

• Kise, Nina Jullum; Roos, Ewa M.; Stensrud, Silje; Engebretsen, Lars & Risberg, May Arna (2018). The 6-m timed hop test is a prognostic factor for outcomes in patients with meniscal tears treated with exercise therapy or arthroscopic partial meniscectomy: a secondary, exploratory analysis of the Odense–Oslo meniscectomy versus exercise (OMEX) trial. Knee Surgery, Sports Traumatology, Arthroscopy. ISSN 0942-2056. p. 1–10. doi: 10.1007/s00167-018-5241-7. Full text in Research Archive Show summary

  Purpose: To identify the prognostic factors for 2-year patient-reported outcomes in middle-aged patients with degenerative meniscal tears treated with exercise therapy (ET) or arthroscopic partial meniscectomy (APM). Methods: One hundred and seven patients, with mean age 49.6 (SD 6.2) years and BMI 25.7 (SD 3.7), were included in this analysis of data from the OMEX trial (http://www.clinicaltrials.gov NCT01002794). Linear and Poisson regression models were built to explore the associations between potential prognostic factors (patient characteristics, knee function-related and disease-related factors) and 2-year patient-reported outcomes: the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales Pain, Symptoms, ADL, Sport/Rec, QoL and 5-point Global Rating of Change scales for knee pain (GRC Pain) and function (GRC Function). Analyses were performed for the whole cohort and for the two treatment groups (n = 55 and 52) with adjustments for age, sex, BMI and baseline KOOS. Results: For the whole cohort, a 1-s better baseline 6-m timed hop test result was associated with 3.1–7.1 points better 2-year scores for all KOOS subscales (95% CIs 1.1–5.2 to 4.1–10.1 points). A 1.61–2.80 s better test was associated with scores equivalent to previously calculated clinical relevant differences for each KOOS subscale. For the groups of patients treated with ET and APM, respectively, 2.09–3.60 s and 0.63–1.99 s better tests were associated with clinical relevant differences. For the whole cohort, a 1-s better test was associated with 26% (95% CI 15–38%) and 22% (95% CI 11–34%) higher possibility for better or much better GRC Pain and Function scores. Patients treated with ET had 17% (95% CI 2–33%) increased possibility for better or much better GRC Pain score, and patients treated with APM had 65% (95% CI 32–108%) and 70% (95% CI 38–109%) increased possibility for better or much better GRC Pain and Function scores. Conclusions: The 6-m timed hop test result was a significant prognostic factor for 2-year patient-reported outcomes in middle-aged patients with degenerative meniscal tears, especially in those treated with APM.

• Holtedahl, Robin; Brox, Jens Ivar; Aune, Arne Kristian; Nguyen, Daniel; Risberg, May Arna & Tjomsland, Ole (2018). Changes in the rate of publicly financed knee arthroscopies: An analysis of data from the Norwegian patient registry from 2012 to 2016. BMJ Open. 8(6), p. 1–6. doi: 10.1136/bmjopen-2017-021199. Full text in Research Archive Show summary

  Objective: To examine rates of publicly financed knee arthroscopic surgery in Norway between 2012 and 2016. Design: Analysis of anonymised data from the National Patient Registry. Interventions: Beginning in 2012, South-Eastern Norway Regional Health Authority implemented administrative measures to bring down rates of knee arthroscopy. Similar measures were not introduced in the other three Regional Health Authorities. Main outcome measures: We analysed annual national rates of publicly financed knee arthroscopies in 2012 and 2016. We compared the rates in South-Eastern Norway Regional Health Authority with corresponding rates in the rest of the country. Variations by county, public hospital versus publicly reimbursed private hospital, gender and age were also assessed. Results: The overall annual rate of arthroscopic procedures declined by 33% from 2012 to 2016, from 310 to 207 per 100 000 inhabitants, respectively. Hospitals in South-Eastern Norway Regional Health Authority reported a 48% reduction, compared with mean 13% in the other three Regional Health Authorities. In public hospitals, rates decreased nationally by 42%, while rates in publicly reimbursed private hospitals increased by 12%. Rates in publicly reimbursed private hospitals decreased by 30% in South-Eastern Norway Regional Health Authority but increased by 63% in the other Regional Health Authorities. The proportion of patients ≥50 years (excluding meniscal repairs) in Norway was 54% in 2012 and fell to 46% in 2016. Average rates per county varied by a factor of 3:1. Conclusion: We report a marked overall reduction of knee arthroscopic procedures from 2012 to 2016 in publicly funded hospitals. The largest decrease was reported in South-Eastern Norway Regional Health Authority, and this coincides in time with implemented administrative measures. The results suggest that the trend of increasing rates of knee arthroscopies can be reversed through purposeful professional and administrative interventions.

• Kise, Nina Jullum; Aga, Cathrine; Engebretsen, Lars; Roos, Ewa M.; Tariq, Rana & Risberg, May Arna (2018). Degenerative meniskrupturer: Kan pre-operative MR-funn og artroskopiske funn predikere knefunksjon etter 1-2 år? Høstmøteboken 2018 - Vitenskapelig program og abstrakter. Norsk ortopedisk forening. p. 84–84. Full text in Research Archive
• Ekås, Guri Ranum; Moksnes, Håvard; Grindem, Hege; Risberg, May Arna & Engebretsen, Lars (2018). Langtidsoppfølging av barn med korsbåndsskade før 13 års alder, Høstmøteboken 2018 - Vitenskapelig program og abstrakter. Norsk ortopedisk forening. p. 98–98. Full text in Research Archive
• Ekås, Guri Ranum; Moksnes, Håvard; Grindem, Hege; Larmo, Arne; Mjelde, Marit & Risberg, May Arna [Show all 7 contributors for this article] (2018). Knepatologi hos unge voksne etter fremre korsbåndsskade før 13 års alder, Høstmøteboken 2018 - Vitenskapelig program og abstrakter. Norsk ortopedisk forening. p. 97–97. Full text in Research Archive
• Kise, Nina Jullum; Roos, Ewa M.; Stensrud, Silje; Engebretsen, Lars & Risberg, May Arna (2018). Seks-meter hinke-test på tid er prognostisk for to-års resultater hos pasioenter med degenerative meniskrupturer, Høstmøteboken 2018 - Vitenskapelig program og abstrakter. Norsk ortopedisk forening. p. 86–86. Full text in Research Archive
• Risberg, May Arna; Steffen, Kathrin; Nilstad, Agnethe; Myklebust, Grethe; Kristianslund, Eirik & Moltubakk, Marie M. [Show all 7 contributors for this article] (2018). Normative Quadriceps and Hamstring Muscle Strength Values for Female, Healthy, Elite Handball and Football Players. Journal of Strength and Conditioning Research. ISSN 1064-8011. 32(8), p. 2314–2323. doi: 10.1519/JSC.0000000000002579. Full text in Research Archive Show summary

  This study presents normative values for isokinetic knee extension and flexion muscle strength tests in 350 elite, female, handball (n = 150) and football (n = 200) players. Isokinetic concentric muscle strength tests at 60°·sec−1 were recorded bilaterally using a dynamometer. Peak torque (in Newton meter [N·m]), body mass normalized peak torque (N·m·kg−1), and hamstring to quadriceps ratio (H:Q ratio) for dominant and nondominant legs were recorded. The female elite players were 20.9 ± 4.0 years, started playing at the elite level at the age of 18.2 ± 2.7 years, with a mean of 9.7 ± 2.2 hours of weekly in-season training. Handball players demonstrated greater quadriceps muscle strength compared with football players (11.0%) (p < 0.001), also when normalized to body mass (4.1%) (p = 0.012), but not for weight-adjusted hamstring muscle strength. The H:Q ratio was higher on the dominant compared with the nondominant leg for handball players only (p = 0.012).The H:Q ratio was significantly lower for handball players (0.58) compared with football players (0.60) (p < 0.02). These normative values for isokinetic knee extension and flexion torques of healthy, elite, female handball and football players can be used to set rehabilitation goals for muscle strength after injury and enable comparison with uninjured legs. Significantly greater quadriceps muscle strength was found for handball players compared with football players, also when normalized to body mass.

• Aga, Cathrine; Risberg, May Arna; Fagerland, Morten; Johansen, Steinar; Trøan, Ingrid & Heir, Stig [Show all 7 contributors for this article] (2018). No Difference in the KOOS Quality of Life Subscore Between Anatomic Double-Bundle and Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction of the Knee: A Prospective Randomized Controlled Trial With 2 Years’ Follow-up. American Journal of Sports Medicine. ISSN 0363-5465. 46(10), p. 2341–2354. doi: 10.1177/0363546518782454. Full text in Research Archive Show summary

  Background: The double-bundle reconstruction technique was developed to resemble the properties of the native anterior cruciate ligament (ACL) more closely than the conventional single-bundle technique. The clinical benefit of the operative procedure is controversial, and there is a need for studies with a focus on patient-reported outcomes (PROs). Study Design: Randomized controlled trial; Level of evidence, 1. Hypothesis: Anatomic double-bundle ACL reconstruction would be superior to anatomic single-bundle reconstruction regarding the change in the Knee injury and Osteoarthritis Outcome Score (KOOS) Quality of Life (QoL) subscore from baseline to 2-year follow-up. Methods: According to sample size calculations, 120 patients aged 18 to 40 years with a primary ACL injury of their knee were randomized to the anatomic double-bundle or anatomic single-bundle reconstruction groups. Patients with posterior cruciate ligament, posterolateral corner, or lateral collateral ligament injuries or with established osteoarthritis were excluded. Patients with residual laxity from a coexistent medial collateral ligament injury were excluded. Data were registered at baseline, 1 year, and 2 years. In 24 patients, postoperative 3-dimensional computed tomography was performed to verify the positioning of the bundles. The outcome measures were the change in KOOS subscores and the International Knee Documentation Committee 2000 subjective score, pivot-shift test result, Lachman test finding, KT-1000 arthrometer measurement, activity level, return-to-sports rate, and osteoarthritic changes on radiographs. A linear mixed model was used for the analysis of all the PROs, including the primary outcome. Results: The change in the KOOS QoL subscore from baseline to 2-year follow-up was not different between the double- and single-bundle groups (mean change, 29.2 points vs 28.7 points, respectively; –0.5-point difference; 95% CI, –8.4 to 7.4 points; P = .91). Neither were there any differences between the 2 groups in the remaining PROs, knee laxity measurements, or activity levels of the patients. Radiological signs of osteoarthritis were found in 2 patients. Eleven patients had a graft rupture: 8 in the single-bundle group and 3 in the double-bundle group (P = .16). Three-dimensional computed tomography of the knees verified the positioning of the anteromedial bundle, posterolateral bundle, and single-bundle grafts to be within acceptable limits. Conclusion: There was no difference in the KOOS QoL subscore, the remaining PROs, knee laxity measurements, or activity levels comparing the double- and single-bundle ACL reconstruction techniques. The number of bundles does not seem to influence clinical and subjective outcomes, as long as the tunnels are adequately positioned.

• Grindem, Hege; Wellsandt, Elizabeth; Failla, Mathew J.; Snyder-Mackler, Lynn & Risberg, May Arna (2018). Anterior Cruciate Ligament Injury—Who Succeeds Without Reconstructive Surgery? The Delaware-Oslo ACL Cohort Study. Orthopaedic Journal of Sports Medicine (OJSM). 6(5). doi: 10.1177/2325967118774255. Full text in Research Archive Show summary

  Background: More than 50% of highly active patients with an anterior cruciate ligament (ACL) injury who choose nonsurgical treatment (active rehabilitation alone) have successful 2-year outcomes and comparable knee function to an uninjured population. Early predictive factors for a successful outcome may aid treatment decision making in this population. Purpose: To identify early predictors of a successful 2-year outcome in those who choose nonsurgical treatment of an ACL injury. Study Design: Cohort study; Level of evidence, 2. Methods: This prospective cohort study consisted of ACL-injured athletes who were consecutively screened for inclusion. A total of 300 patients were included from 2 sites (Oslo, Norway, and Delaware, USA), and the 118 patients who initially chose not to undergo ACL reconstruction were included. All patients participated in pivoting sports before the injury, and none had significant concomitant injuries. A successful 2-year outcome was defined as having 2-year International Knee Documentation Committee (IKDC) scores ≥15th normative percentile and not undergoing ACL reconstruction. Multivariable logistic regression models were built using demographic and knee function data (quadriceps muscle strength, 4 single-leg hop tests, IKDC score, and Knee Outcome Survey–Activities of Daily Living Scale [KOS-ADLS] score) collected at baseline or after a 5-week neuromuscular and strength training (NMST) rehabilitation program. Results: After 2 years, 52 of 97 (53.6%) patients had a successful outcome. In the multivariable baseline model, older age, female sex, better performance on the single-leg hop test, and a higher KOS-ADLS score were significantly associated with successful 2-year outcomes. After the 5-week NMST rehabilitation program, older age, female sex, and a higher IKDC score increased the odds of a successful 2-year outcome. The 2 models had comparable predictive accuracy (post-NMST area under the curve [AUC], 0.78 [95% CI, 0.68-0.88]; baseline AUC, 0.81 [95% CI, 0.72-0.89]). Conclusion: Clinicians and patients can be more confident in a nonsurgical treatment choice (active rehabilitation alone) in athletes who are female, are older in age, and have good knee function, as measured by single-leg hop tests and patient-reported outcome measures, early after an ACL injury. Prediction models that include measures of knee function, assessed either before or after rehabilitation, can estimate 2-year prognoses for nonsurgical treatment and thereby assist shared treatment decision making.

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• Killingmo, Rikke Munk; Øiestad, Britt Elin; Risberg, May Arna; Maas, Esther & Grotle, Margreth (2025). Cost-effectiveness of strength exercise or aerobic exercise compared to usual care for patients with knee osteoarthritis: a multi-arm randomised controlled trial. Full text in Research Archive
• Killingmo, Rikke Munk; Øiestad, Britt Elin; Risberg, May Arna; Maas, Esther & Grotle, Margreth (2024). Cost-effectiveness of strength exercise or aerobic exercise compared with usual care for patients with knee osteoarthritis: secondary results from a multiarm randomised controlled trial in Norway. BMJ Open. 14(5). doi: 10.1136/bmjopen-2023-079704. Full text in Research Archive
• Killingmo, Rikke Munk; Øiestad, Britt Elin; Risberg, May Arna; Maas, Esther & Grotle, Margreth (2024). Kostnadseffektiviteten av styrketrening eller aerob trening sammenlignet med vanlig behandling for pasienter med kneartrose en flerarmet randomisert kontrollert studie. Full text in Research Archive
• Killingmo, Rikke Munk; Øiestad, Britt Elin; Risberg, May Arna; Maas, Esther & Grotle, Margreth (2024). Cost-effectiveness of strength exercise or aerobic exercise compared to usual care for patients with knee osteoarthritis: a multi-arm randomised controlled trial. Full text in Research Archive
• Jakobsen, Rune Bruhn; Tveiten, Caroline Emilie Van Woensel Ko; Løken, Sverre Bertrand; Persson, Andreas; Moksnes, Håvard & Grindem, Hege [Show all 7 contributors for this article] (2024). Siste nytt om fremre korsbånd hos idrettsutøvere. Full text in Research Archive
• Killingmo, Rikke Munk; Øiestad, Britt Elin; Risberg, May Arna; Maas, Esther & Grotle, Margreth (2024). Cost-effectiveness of strength exercise or aerobic exercise compared to usual care for patients with knee osteoarthritis: a multi-arm randomised controlled trial. Full text in Research Archive
• Killingmo, Rikke Munk; Øiestad, Britt Elin; Risberg, May Arna; Maas, Esther & Grotle, Margreth (2023). Kostnadseffektiviteten av styrketrening eller aerob trening sammenlignet med vanlig behandling for pasienter med kneartrose en flerarmet randomisert kontrollert studie. Full text in Research Archive
• Killingmo, Rikke Munk; Øiestad, Britt Elin; Risberg, May Arna; Maas, Esther & Grotle, Margreth (2023). Kostnadseffektiviteten av styrketrening eller aerob trening sammenlignet med vanlig behandling for pasienter med kneartrose en flerarmet randomisert kontrollert studie. Full text in Research Archive
• Urhausen, Anouk; Pedersen, Marie; Grindem, Hege; Gunderson, Ragnhild B.; Aune, Arne Kristian & Engebretsen, Lars [Show all 11 contributors for this article] (2023). Lav grad av artrose og gode pasientrapporterte utfall 10 år etter korsbåndskade – Delaware-Oslo ACL kohorten. Full text in Research Archive
• Øiestad, Britt Elin; Årøen, Asbjørn; Røtterud, Jan Harald; Østerås, Nina; Jarstad, Even & Grotle, Margreth [Show all 7 contributors for this article] (2023). The efficacy of strength or aerobic exercise on quality of life and knee function in patients with knee osteoarthritis. A multi-arm randomized controlled trial with 1-year follow-up. Full text in Research Archive
• Urhausen, Anouk; Pedersen, Marie; Grindem, Hege; Gunderson, Ragnhild B.; Aune, Arne Kristian & Engebretsen, Lars [Show all 11 contributors for this article] (2023). Lav grad av artrose og gode pasientrapporterte utfall 10 år etter korsbåndskade – Delaware-Oslo ACL kohorten. Full text in Research Archive
• Aga, Cathrine; Trøan, Ingrid; Tariq, Rana; Heir, Stig; Risberg, May Arna & Johansen, Steinar [Show all 8 contributors for this article] (2023). Ingen forskjell i artroseutvikling etter 5 år - anatomisk Double-bundle versus Singlebundle ACL rekonstruksjons teknikk. Full text in Research Archive
• Øiestad, Britt Elin; Aarøen, Asbjørn; Røtterud, Jan Harald; Østerås, Nina; Jarstad, Even & Grotle, Margreth [Show all 7 contributors for this article] (2022). Effekten av to ulike treningsprogrammer på knerelatert livskvalitet hos personer med kneleddsartrose. En randomisert kontrollert studie. Full text in Research Archive
• Øiestad, Britt Elin; Aarøen, Asbjørn; Røtterud, Jan Harald; Østerås, Nina; Jarstad, Even & Grotle, Margreth [Show all 7 contributors for this article] (2022). Effekten av to ulike treningsprogrammer på livskvalitet hos personer med kneleddsartrose. En randomisert kontrollert studie. Full text in Research Archive
• Urhausen, Anouk; Grindem, Hege & Risberg, May Arna (2022). Beregning av cutoffs for pasientrapporterte utfallsmål for tilfredsstillende knefunksjon 10 år etter en fremre korsbåndskade. Full text in Research Archive
• Øiestad, Britt Elin; Årøen, Asbjørn; Røtterud, Jan H; Østerås, Nina; Jarstad, Even & Grotle, Margreth [Show all 7 contributors for this article] (2022). Effekt av to ulike treningsprogram for pasienter med symptomatisk kneartrose. En klinisk randomisert kontrollert studie. Full text in Research Archive
• Urhausen, Anouk; Grindem, Hege & Risberg, May Arna (2022). Hvordan påvirker preoperativ og postoperativ rehabilitering knefunksjonen 10 år etter fremre korsbåndrekonstruksjon? Full text in Research Archive
• Berg, Bjørnar; Roos, Ewa M.; Kise, Nina Jullum; Engebretsen, Lars; Holm, Inger & Risberg, May Arna (2021). Muskelstyrke og artroseprogresjon etter kirurgi eller treningsterapi for degenerative meniskrupturer: Sekundæranalyse av en randomisert studie. Full text in Research Archive
• Roos, Ewa M.; Risberg, May Arna & Little, C.B. (2021). Prevention and early treatment, a future focus for OA research. Osteoarthritis and Cartilage. ISSN 1063-4584. 29(12), p. 1627–1629. doi: 10.1016/j.joca.2021.10.007. Full text in Research Archive
• Berg, B.; Roos, Ewa M.; Kise, Nina Jullum; Engebretsen, Lars & Risberg, May Arna (2020). Response to Letter to the Editor: “Osteoarthritis progression after exercise therapy or meniscectomy in patients with degenerative meniscal tears”. Osteoarthritis and Cartilage. ISSN 1063-4584. 28(8), p. 1148–1149. doi: 10.1016/j.joca.2020.05.003. Full text in Research Archive
• Risberg, May Arna (2020). How to protect long-term knee health after anterior cruciate ligament(ACL) injury. Full text in Research Archive
• Lund, Jonas; Risberg, May Arna & Øiestad, Britt Elin (2020). The association between physical fitness and self-efficacy in knee osteoarthritis. Full text in Research Archive
• Lund, Jonas; Risberg, May Arna & Øiestad, Britt Elin (2020). The association between physical fitness and self-efficacy in patients with knee osteoarthritis. Full text in Research Archive
• Reiman, Michael P.; Agricola, Rintje; Kemp, Joanne; Heerey, Joshua J.; Weir, Adam & Klij, Pim van [Show all 44 contributors for this article] (2020). Infographic. Consensus recommendations on the classification, definition and diagnostic criteria of hiprelated pain in young and middle-aged active adults from the International Hip-related Pain Research Network, Zurich 2018. British Journal of Sports Medicine. ISSN 0306-3674. doi: 10.1136/bjsports-2020-102219. Full text in Research Archive
• Øiestad, Britt Elin; Kristiansen, Sverre; Jarstad, Even & Risberg, May Arna (2020). PHYSICAL FITNESS IN INDIVIDUALS WITH KNEE OSTEOARTHRITIS COMPARED TO NORMATIVE DATA - A CROSSSECTIONAL STUDY. Full text in Research Archive
• Capin, Jacob John; Snyder-Mackler, Lynn; Risberg, May Arna & Grindem, Hege (2019). Keep calm and carry on testing: A substantive reanalysis and critique of 'what is the evidence for and validity of return-to-sport testing after anterior cruciate ligament reconstruction surgery? A systematic review and meta-analysis'. British Journal of Sports Medicine. ISSN 0306-3674. p. 1–3. doi: 10.1136/bjsports-2019-100906. Full text in Research Archive
• Lie, Marthe Mehu; Risberg, May Arna; Storheim, Kjersti; Engebretsen, Lars & Øiestad, Britt Elin (2019). What's the rate of knee osteoarthritis 10 years after anterior cruciate ligament injury? An updated systematic review. Full text in Research Archive
• Hilde, Gunvor; Bergland, Astrid; Risberg, May Arna & Pripp, Are Hugo (2019). Better before-better after: efficacy of prehabilitation for older patients with osteoarthritis awaiting total hip replacement-a study protocol for a randomised controlled trial in South-Eastern Norway. BMJ Open. doi: 10.1136/bmjopen-2019-031626. Full text in Research Archive
• Aga, Cathrine; Risberg, May Arna; Johansen, Steinar; Fagerland, M; Heir, Stig & Engebretsen, Lars (2018). No difference in the KOOS quality of life after two years, between anatomic Double-bundle and anatomic Single-bundle ACL reconstructed patients - a prospectively, randomised, controlled trial of 120 patients. Full text in Research Archive
• Risberg, May Arna; Tryggestad, C; Nordsletten, Lars; Engebretsen, Lars & Holm, Inger (2018). Active living with osteoarthritis - implementation of evidence-based guidelines as first-line treatment for patients with knee and hip osteoarthritis. Full text in Research Archive
• Grindem, Hege; Failla, M; Wellsandt, Elizabeth; Snyder-Mackler, Lynn & Risberg, May Arna (2018). Anterior cruciate ligament injury: who succeeds without reconstructive surgery? Knee Surgery, Sports Traumatology, Arthroscopy. ISSN 0942-2056. 26, p. 212–213. Full text in Research Archive

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