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Musculoskeletal injury (MSKI) is the most common reason for short-term occupational limitation and subsequent medically related early departure from the military. MSKI-related medical discharge/separation occurs when service personnel are unable to perform their roles due to pain or functional limitations associated with long-term conditions, including osteoarthritis (OA). There is a clear link between traumatic knee injuries, such as anterior cruciate ligament or meniscal, and the development of post-traumatic OA (PTOA). Notably, PTOA is the leading cause of disability following combat injury. Primary injury prevention strategies exist within the military, with interventions focused on conditioning, physical health and leadership. However, not every injury can be prevented, and there is a need to develop secondary prevention to mitigate or reduce the risk of PTOA following an MSKI. Two international collaborative groups, OPTIKNEE and OA Action Alliance, recently produced rigorous evidence-based consensus statements for the secondary prevention of OA following a traumatic knee injury, including consensus definitions and clinical and research recommendations. These recommendations focus on patient-centred lifespan interventions to optimise joint health and prevent lost decades of care. This article aims to describe their relevance and applicability to the military population and outline some of the challenges associated with service life that need to be considered for successful integration into military care pathways and research studies., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Individuals who are living with obesity often adopt alternative lower limb walking mechanics compared to persons with a healthy weight. Stair negotiation is a common activity of daily living that, when used consistently with diet and other physical activity, can help promote the reversal of health-related risk factors associated with people who are obese. The purpose of this study was to determine how stair negotiation affects normalized and non-normalized peak knee extension and abduction moments in young adults who live with obesity (BMI between 30 and 40 kg/m 2 ) compared to adults with a healthy weight (BMI between 18.5 and 25 kg/m 2 )., Methods: Fifteen young adults living with obesity and fifteen with a healthy weight performed stair ascent and descent walking trials on a 3-step instrumented staircase at a self-selected walking speed. A one-way ANCOVA (covariate: gait speed) was used to compare knee moment variables between groups., Results: No significant differences were found between groups in peak knee joint moments normalized to body mass. The individuals living with obesity demonstrated significantly larger non-normalized peak knee extension moments during stair ascent and descent but no differences in the non-normalized peak knee abduction moments for stair ascent or descent., Conclusion: Results of this study indicate differences in non-normalized peak knee extension moments between BMI groups. The young age of the obese group may have contributed to minimal differences overall. Future research should determine how these findings differ in an older obese population and how using a handrail would affect these results., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: The purpose was to explore quadriceps electromechanical function (quadriceps latency) during gait after anterior cruciate ligament injury as a predictor for radiographic knee osteoarthritis 6-years after anterior cruciate ligament reconstruction. Change in latency after preoperative physical therapy was also examined., Methods: Quadriceps latency (time between peak knee moment and quadriceps electromyography) was calculated before preoperative physical therapy (2.4 [0.5-7.5] months after anterior cruciate ligament injury) and after preoperative physical therapy in 24 athletes. Participants were dichotomized into osteoarthritis (Kellgren and Lawrence grade ≥ 2) and non-osteoarthritis groups at 6-years. Forward selection logistic regression was performed using z-score normalized quadriceps latency and demographics. A 2 × 2 repeated measure ANOVA was performed for quadriceps latency between groups before and after preoperative physical therapy., Findings: Quadriceps latency before preoperative physical therapy was the only predictor of 6-year radiographic osteoarthritis (p = 0.014, odds ratio [95% confidence interval] = 5.859 [1.435-23.924]). Time by group interaction was observed for quadriceps latency (p = 0.039, η 2 p = 0.179). In the osteoarthritis group, latency may reduce after training (before preoperative physical therapy = 115.7 ± 20.6 ms, after preoperative physical therapy = 99.5 ± 24.0 ms, p = 0.082)., Interpretation: Prolonged latency after anterior cruciate ligament injury may predict post-traumatic knee osteoarthritis 6-years after anterior cruciate ligament reconstruction. Latency may shorten with preoperative physical therapy, yet athletes still moved on to develop osteoarthritis. Quadriceps function may need intervention immediately following anterior cruciate ligament injury for prevention of post-traumatic knee osteoarthritis., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Lynn Snyder-Mackler reports financial support was provided by National Institutes of Health. Thomas Buchanan reports financial support was provided by National Institute of Health. Jacob Capin reports financial support was provided by National Institutes of Health. Elizabeth Wellsandt reports financial support was provided by National Institutes of Health. Elanna Arhos reports financial support was provided by National Institutes of Health. Elanna Arhos reports financial support was provided by Foundation for Physical Therapy. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Single-legged hop tests have been widely used to assess performance-based outcomes after anterior cruciate ligament (ACL) reconstruction. Traditional single, triple, or 6-meter (6m) timed hop tests only measure distance or time as the principal variables, neglecting other variables, such as individual hop distances within a series of hops, flight time, and stance time. The development of portable instrumented pressure walkways has made it possible to collect parameters such as hop velocity, flight time, stance time, distance, and pressure outside of a laboratory setting. However, the reliability of instrumented pressure walkways in measuring spatial and temporal variables during single-legged hop tests is unknown. This study aimed to determine if the Zeno walkway can reliably measure spatiotemporal (ST) characteristics of hop tests., Study Design: Cross-Sectional Study., Methods: Individuals (n=38) in this cross-sectional study performed single, triple, and 6m hop tests on a pressure-sensitive Zeno walkway. Twenty-one participants completed follow-up testing between one and 14 days later. Intraclass correlation coefficients (ICC(3,k)) were used to assess test-retest reliability of ST variables. The accuracy of vertical jump height and 6m hop timing were also measured., Results: All ST variables demonstrated excellent test-retest reliability (ICC > 0.86) with small minimal detectable change (MDC) values during single-legged hop tests. Six-meter hop time and jump height during a bilateral drop jump were also accurately measured by the walkway., Conclusion: An instrumented pressure walkway is a novel tool to reliably assess non-traditional parameters of clinically relevant hop and jump tests such as flight time, stance time, and jump height after lower extremity injury, surgery, and rehabilitation., Level of Evidence: 3b., Competing Interests: The authors report no conflicts of interest., (© The Author(s).)

Background: Spatiotemporal parameters of gait are useful for identifying pathological gait patterns and presence of impairments. Reliability of the pressure-sensitive Zeno TM Walkway has not been established in young, active individuals without impairments, and no studies to this point have included running., Purpose: The purposes of this study were to 1) determine if up to two additional trials of walking and running on the Zeno TM Walkway are needed to produce consistent measurements of spatiotemporal variables, and 2) establish test-retest reliability and minimal detectable change (MDC) values for common spatiotemporal variables measured during walking and running., Study Design: Cross-Sectional Laboratory Study., Methods: Individuals (n=38) in this cross-sectional study walked and ran at self-selected comfortable speed on a pressure-sensitive Zeno TM Walkway. Twenty-one participants returned for follow-up testing between one and 14 days later. Intraclass correlation coefficients (ICCs) were used to assess reliability of spatiotemporal variable means using three, four, or five passes over the Zeno TM Walkway and to assess test-retest reliability of spatiotemporal variables across sessions., Results: All variables showed excellent reliability (ICC > 0.995) for walking and running when measured using three, four, or five passes. Additionally, all variables demonstrated moderate to excellent test-retest reliability during walking (ICC: 0.732-0.982) and running (ICC: 0.679-0.985)., Conclusion: This study establishes a reliable measurement protocol of three one-way passes when using the Zeno TM Walkway for walking or running analysis. This is the first study to establish reliability of the Zeno TM Walkway during running and in young, active individuals without neuromusculoskeletal pathology., Level of Evidence: 3b., Competing Interests: None, (© The Author(s).)

Background: Psychological response is important in return-to-sport decisions for athletes recovering from anterior cruciate ligament reconstruction (ACLR). The purpose of this study was to compare psychological response after ACLR with a concomitant meniscus repair compared to isolated ACLR., Methods: Thirty-five individuals completed the Tampa Scale of Kinesiophobia (TSK) and Anterior Cruciate Ligament Return-to-Sport after Injury (ACL-RSI) scale before ACLR and 2, 4, and 6 months after ACLR. Participants were dichotomized based on presence of concomitant meniscus repair (Yes/No). Separate group X time repeated measures analyses of variance were conducted for both scales., Results: Participants were 65.7% female, 19.1 ± 4.7 years old with BMI of 24.9 ± 4.4 kg/m 2 . Sixteen individuals had an isolated ACLR with 19 individuals having an ACLR with concomitant meniscus repair. For the TSK, there was a group × time interaction effect(p = 0.028), with improvement in TSK scores for the isolated ACLR group (ACLR:2 months = 24.8 ± 3.7; 4 months = 22.0 ± 5.7; 6 months: 19.9 ± 5.9; Meniscus Repair:2 months = 25.5 ± 4.7; 4 months = 24.1 ± 5.0; 6 months: 23.8 ± 4.7). Six months after ACLR, TSK scores were worse in the meniscus repair group(p = 0.036). For the ACL-RSI, there was no interaction(p = 0.07)., Conclusion: Concomitant meniscus repair with ACLR results in less post-operative improvement in kinesiophobia through 6 months after ACLR compared to isolated ACLR., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: We aimed to identify important components of, and practical resources relevant for inclusion in, a toolkit to aid exercise delivery for people with hip/knee osteoarthritis., Method: An online international multi-disciplinary survey was conducted across 43 countries (139 clinicians, 44 people with hip/knee osteoarthritis and 135 osteoarthritis researchers). Participants were presented with the seeding statement 'Practical resources to aid the implementation of exercise for people with hip/knee osteoarthritis should…' and asked to provide up to 10 open text responses. Responses underwent refinement and qualitative content analysis to create domains and categories., Results: Refinement of 551 open text responses yielded 72 unique statements relevant for analysis. Statements were organised into nine broad domains, suggesting that resources to aid exercise delivery should: (1) be easily accessible; (2) be of high quality; (3) be developed by, and for, stakeholders; (4) include different ways of delivering information; (5) include different types of resources to support exercise and non-exercise components of self-management; (6) include resources on recommended exercises and how to perform/progress them; (7) include tools to support motivation and track progress; (8) include resources to enable tailoring of the programme to the individual and; (9) facilitate access to professional and peer support., Conclusion: Our findings identified important components of, and practical resources to include within, a toolkit to aid delivery of exercise for people with hip/knee osteoarthritis. These findings have implications for exercise providers and lay the foundation for the development of a toolkit to help ensure exercise provision aligns with current international recommendations., (© 2023 John Wiley & Sons Ltd.)

Objective: To evaluate the association of baseline factors with rehabilitation dose and the association of rehabilitation dose with meaningful change in physical function, pain, and fatigue over 6 months among adults with rheumatoid arthritis (RA)., Methods: Using data from the National Databank for Rheumatic Diseases registry, we extracted baseline characteristics and self-reported physical function (Health Assessment Questionnaire), pain (visual analog scale [VAS]), fatigue (VAS), rehabilitation dose (low: 1-2 visits, medium: 3-8 visits, high: >8 visits), and follow-up outcomes 6 months later. Changes in clinical outcomes were categorized as improved, no change, or worsened. We calculated odds ratios (ORs) and 95% confidence intervals (95% CIs) using proportional odds logistic regression models to examine the association of the baseline factors with rehabilitation dose and the association of rehabilitation dose with changes in clinical outcomes, adjusting for potential confounders., Results: The sample included 1,381 adults with a new episode of rehabilitation (dose: low 27%, medium 42%, high 31%). Worse baseline physical function (adjusted OR 1.29 [95% CI 1.04-1.60]), but not pain (adjusted OR 1.04 [95% CI 0.99-1.10]) or fatigue (adjusted OR 0.98 [95% CI 0.93-1.03]), were associated with a higher rehabilitation dose. A high rehabilitation dose was associated with a favorable change in physical function (OR 1.51 [95% CI 1.14-1.98]), pain (OR 1.44 [95% CI 1.06-1.96]), and fatigue (OR 1.45 [95% CI 1.06-1.99]) compared to a low dose; only the association with physical function change persisted in adjusted models (adjusted OR 1.41 [95% CI 1.03-1.92])., Conclusion: Using real-world data, this study supports a higher rehabilitation dose to improve physical function in adults with RA., (© 2022 American College of Rheumatology.)

After an anterior cruciate ligament (ACL) injury, people need secondary prevention strategies to identify osteoarthritis at its earliest stages so that interventions can be implemented to halt or slow the progression toward its long-term burden. The Osteoarthritis Action Alliance formed an interdisciplinary Secondary Prevention Task Group to develop a consensus on recommendations to provide clinicians with secondary prevention strategies that are intended to reduce the risk of osteoarthritis after a person has an ACL injury. The group achieved consensus on 15 out of 16 recommendations that address patient education, exercise and rehabilitation, psychological skills training, graded-exposure therapy, cognitive-behavioral counseling (lacked consensus), outcomes to monitor, secondary injury prevention, system-level social support, leveraging technology, and coordinated care models. We hope this statement raises awareness among clinicians and researchers on the importance of taking steps to mitigate the risk of osteoarthritis after an ACL injury., (© by the National Athletic Trainers' Association, Inc.)

Context: The Osteoarthritis Action Alliance formed a secondary prevention task group to develop a consensus on secondary prevention recommendations to reduce the risk of osteoarthritis after a knee injury., Objective: Our goal was to provide clinicians with secondary prevention recommendations that are intended to reduce the risk of osteoarthritis after a person has sustained an anterior cruciate ligament injury. Specifically, this manuscript describes our methods, literature reviews, and dissenting opinions to elaborate on the rationale for our recommendations and to identify critical gaps., Design: Consensus process., Setting: Virtual video conference calls and online voting., Patients or Other Participants: The Secondary Prevention Task Group consisted of 29 members from various clinical backgrounds., Main Outcome Measure(s): The group initially convened online in August 2020 to discuss the target population, goals, and key topics. After a second call, the task group divided into 9 subgroups to draft the recommendations and supportive text for crucial content areas. Twenty-one members completed 2 rounds of voting and revising the recommendations and supportive text between February and April 2021. A virtual meeting was held to review the wording of the recommendations and obtain final votes. We defined consensus as >80% of voting members supporting a proposed recommendation., Results: The group achieved consensus on 15 of 16 recommendations. The recommendations address patient education, exercise and rehabilitation, psychological skills training, graded-exposure therapy, cognitive-behavioral counseling (lacked consensus), outcomes to monitor, secondary injury prevention, system-level social support, leveraging technology, and coordinated care models., Conclusions: This consensus statement reflects information synthesized from an interdisciplinary group of experts based on the best available evidence from the literature or personal experience. We hope this document raises awareness among clinicians and researchers to take steps to mitigate the risk of osteoarthritis after an anterior cruciate ligament injury., (© by the National Athletic Trainers' Association, Inc.)

Osteoarthritis is a debilitating chronic condition involving joint degeneration, impacting over 300 million people worldwide. This places a high social and economic burden on society. The knee is the most common joint impacted by osteoarthritis. A common cause of osteoarthritis is traumatic joint injury, specifically injury to the anterior cruciate ligament. The purpose of this review is to detail the non-modifiable and modifiable risk factors for osteoarthritis with particular focus on individuals after anterior cruciate ligament injury. After reading this, health care providers will better comprehend the wide variety of factors linked to osteoarthritis., Competing Interests: Disclosure There are no commercial or financial conflicts of interest to report for any of the author team., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Patellar tendinopathy is a common yet misunderstood condition that afflicts a variety of patient populations. This lack of understanding affects the ability of clinicians to provide effective treatment interventions. Patients with tendinopathy often report long-term and low to moderate levels of pain, diminished flexibility, and reduced strength, as well as decreased physical function. Load-management strategies combined with exercise regimens focused on progressive tendon loading are the most effective treatment options for patients with patellar tendinopathy. This review will provide an evidence-based approach to patellar tendinopathy, including its pathoetiology, evaluation, and treatment strategies., (© by the National Athletic Trainers' Association, Inc.)

Osteoarthritis (OA) is prevalent after anterior cruciate ligament (ACL) injury, but mechanismsunderlying its development are poorly understood. The purpose of this study was to determine if gait biomechanics and daily physical activity (PA) associate with cartilage T2 relaxation times, a marker of collagen organization and water content, 1 month after ACL injury. Twenty-seven participants (15-35 years old) without chondral lesions completed magnetic resonance imaging, three-dimensional gait analysis, and 1 week of PA accelerometry. Interlimb differences and ratios were calculated for gait biomechanics and T2 relaxation times, respectively. Multiple linear regression models adjusted for age, sex, and concomitant meniscus injury were used to determine the association between gait biomechanics and PA with T2 relaxation times, respectively. Altered knee adduction moment (KAM) impulse, less knee flexion excursion (kEXC) and higher daily step counts accounted for 35.8%-65.8% of T2 relaxation time variation in the weightbearing and posterior cartilage of the medial and lateral compartment (all p ≤ .011). KAM impulse was the strongest factor for T2 relaxation times in all models (all p ≤ .001). Lower KAM impulse associated with longer T2 relaxation times in the injured medial compartment (β = -.720 to -.901) and shorter T2 relaxation in the lateral compartment (β = .713 to .956). At 1 month after ACL injury, altered KAM impulse, less kEXC, and higher PA associated with longer T2 relaxation times, which may indicate poorer cartilage health. Statement of Clinical Significance: Gait biomechanics and daily PA are modifiable targets that may improve cartilage health acutely after ACL injury and slow progression to OA., (© 2021 Orthopaedic Research Society. Published by Wiley Periodicals LLC.)

Therapeutic exercise is a recommended first-line treatment for patients with knee and hip osteoarthritis (OA); however, there is little specific advice or practical resources to guide clinicians in its implementation. As the first in a series of projects by the Osteoarthritis Research Society International Rehabilitation Discussion Group to address this gap, we aim in this narrative review to synthesize current literature informing the implementation of therapeutic exercise for patients with knee and hip OA, focusing on evidence from systematic reviews and randomized controlled trials. Therapeutic exercise is safe for patients with knee and hip OA. Numerous types of therapeutic exercise (including aerobic, strengthening, neuromuscular, mind-body exercise) may be utilized at varying doses and in different settings to improve pain and function. Benefits from therapeutic exercise appear greater when dosage recommendations from general exercise guidelines for healthy adults are met. However, interim therapeutic exercise goals may also be useful, given that many barriers to achieving these dosages exist among this patient group. Theoretically-informed strategies to improve adherence to therapeutic exercise, such as patient education, goal-setting, monitoring, and feedback, may help maintain participation and optimize clinical benefits over the longer term. Sedentary behavior is also a risk factor for disability and lower quality of life in patients with knee and hip OA, although limited evidence exists regarding how best to reduce this behavior. Current evidence can be used to inform how to implement best practice therapeutic exercise at a sufficient and appropriate dose for patients with knee and hip OA., (© 2020, American College of Rheumatology.)

Several negative adaptations to the musculoskeletal system occur following anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) such as arthrogenic muscle inhibition, decreased lower extremity muscle size, strength, power, as well as alterations to bone and cartilage. These changes have been associated with worse functional outcomes, altered biomechanics, and increased risk for re-injury and post-traumatic osteoarthritis. After ACL injury and subsequent ACLR, examination and evaluation of the musculoskeletal system is paramount to guiding clinical decision making during the rehabilitation and the return to sport process. The lack of access many clinicians have to devices necessary for gold standard assessment of muscle capacities and force profiles is often perceived as a significant barrier to best practices. Fortunately, testing for deficits can be accomplished with methods available to the clinician without access to costly equipment or time-intensive procedures. Interventions to address musculoskeletal system deficits can be implemented with a periodized program. This allows for restoration of physical capacities by adequately developing and emphasizing physical qualities beginning with mobility and movement, and progressing to work capacity and neuromuscular re-education, strength, explosive strength, and elastic or reactive strength. Additional considerations to aid in addressing strength deficits will be discussed such as neuromuscular electrical stimulation, volume and intensity, eccentric training, training to failure, cross-education, and biomechanical considerations. The American Physical Therapy Association adopted a new vision statement in 2013 which supported further development of the profession's identity by promoting the movement system, yet validation of the movement system has remained a challenge. Application of a multi-physiologic systems approach may offer a unique understanding of the musculoskeletal system and its integration with other body systems after ACLR. The purpose of this clinical commentary is to highlight important musculoskeletal system considerations within a multi-physiologic system approach to human movement following ACLR., Level of Evidence: 5., Competing Interests: The authors have declared no conflict of interest.

Gait biomechanics after anterior cruciate ligament (ACL) injury are associated with functional outcomes and the development of posttraumatic knee osteoarthritis. However, biomechanical outcomes between patients treated nonoperatively compared with operatively are not well understood. The primary purpose of this study was to compare knee joint contact forces, angles, and moments during loading response of gait between individuals treated with operative compared with nonoperative management at 5 years after ACL injury. Forty athletes treated operatively and 17 athletes treated nonoperatively completed gait analysis at 5 years after ACL reconstruction or completion of nonoperative rehabilitation. Medial compartment joint contact forces were estimated using a previously validated, patient-specific electromyography-driven musculoskeletal model. Knee joint contact forces, angles, and moments were compared between the operative and nonoperative group using mixed model 2 × 2 analyses of variance. Peak medial compartment contact forces were larger in the involved limb of the nonoperative group (Op: 2.37 ± 0.47 BW, Non-Op: 3.03 ± 0.53 BW; effect size: 1.36). Peak external knee adduction moment was also larger in the involved limb of the nonoperative group (Op: 0.25 ± 0.08 Nm/kg·m, Non-Op: 0.32 ± 0.09 Nm/kg·m; effect size: 0.89). No differences in radiographic tibiofemoral osteoarthritis were present between the operative and nonoperative groups. Overall, participants treated nonoperatively walked with greater measures of medial compartment joint loading than those treated operatively, while sagittal plane group differences were not present. Statement of clinical relevance: The differences in medial knee joint loading at 5 years after operative and nonoperative management of ACL injury may have implications on the development of posttraumatic knee osteoarthritis., (© 2020 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Objective: To determine differences in shoulder range of motion, strength, and upper quarter dynamic balance between collegiate overhead athletes with and without a history of a shoulder injury., Design: Cross-sectional study., Setting: Athletic training clinic., Participants: 58 overhead athletes who were fully participating in NCAA Division I overhead sports (baseball, softball, volleyball, and tennis) and free of any current shoulder injury were included. Participants were divided into a shoulder injury history group (n = 25) and uninjured group (n = 33). Participants in the shoulder injury history group had a previously resolved shoulder injury., Main Outcome Measures: Active range of motion assessments for shoulder internal rotation, external rotation, and horizontal adduction. Isometric strength assessments for shoulder IR and ER. The Upper Quarter Y-Balance Test., Results: The shoulder injury history group demonstrated a lower Upper Quarter Y-Balance Test mean score in the superolateral direction (p = .03, d = 0.56), but no group differences existed for other results (p > .05)., Conclusions: Overhead athletes with a history of shoulder injury had worse upper quarter dynamic balance versus those without the history. From a clinical perspective, the findings may have significant implications for developing shoulder re-injury prevention and rehabilitation protocols in relation to their shoulder injury history., Competing Interests: Declaration of competing interest None declared., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: The use of various single-joint proprioception measurements has resulted in contradictory findings after knee arthroplasty. The use of balance as a surrogate measure to assess knee proprioception post-operation has resulted in further confusion. The aim of this study was to measure single joint knee proprioception in participants after unilateral knee arthroplasty, and compares it to multi-joint balance., Methods: Eleven participants at 1 year after unilateral total knee arthroplasty and twelve age-matched controls were enrolled. The threshold to detect passive motion and the sensory organization test were used to measure single joint knee proprioception and multi-joint balance respectively. Two-way ANOVA and independent t-tests were used to measure differences between and within groups. Regression analysis was used to measure the association between proprioception and balance measurements., Findings: Surgical knees demonstrated significantly more deficient proprioception compared to the non-surgical knees and both knees of the control groups during flexion (P < 0.01) and extension (P < 0.05). Non-surgical knees showed similar proprioception to both knees of the control group during flexion and extension. Within the knee arthroplasty group, only deficiencies during flexion showed significant correlation with Sensory Organization Test visual ratio. No additional differences between both groups during balance measurements, nor any correlations between local joint proprioception and balance were seen., Interpretation: These findings indicate deficient surgical knee proprioception in participants one year after unilateral total knee arthroplasty. Limited associations between measurements indicate that balance may be a poor measure of single-joint proprioception., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The mechanism of knee osteoarthritis development after anterior cruciate ligament injuries is poorly understood. The objective of this study was to evaluate knee gait variables, muscle co-contraction indices and knee joint loading in young subjects with anterior cruciate ligament deficiency (ACLD, n = 36), versus control subjects (n = 12). A validated, electromyography-informed model was used to estimate joint loading. For the involved limb of ACLD subjects versus control, muscle co-contraction indices were higher for the medial (p = 0.018, effect size = 0.93) and lateral (p = 0.028, effect size = 0.83) agonist-antagonist muscle pairs. Despite higher muscle co-contraction, medial compartment contact force was lower for the involved limb, compared to both the uninvolved limb (mean difference = 0.39 body weight, p = 0.009, effect size = 0.70) as well as the control limb (mean difference = 0.57 body weight, p = 0.007, effect size = 1.14). Similar observations were made for total contact force. For involved versus uninvolved limb, the ACLD group demonstrated lower vertical ground reaction force (mean difference = 0.08 body weight, p = 0.010, effect size = 0.70) and knee flexion moment (mean difference = 1.32% body weight * height, p = 0.003, effect size = 0.76), during weight acceptance. These results indicate that high muscle co-contraction does not always result in high knee joint loading, which is thought to be associated with knee osteoarthritis. Long-term follow-up is required to evaluate how gait alterations progress in non-osteoarthritic versus osteoarthritic subjects. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res., (© 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Background: The risk for knee osteoarthritis (OA) is substantially increased after anterior cruciate ligament (ACL) injury. Tools are needed to identify characteristics of patients after ACL injury who are most at risk for posttraumatic OA., Purpose: To determine whether clinical measures of knee function after ACL injury are associated with the development of radiographic knee OA 5 years after injury., Study Design: Cohort study; Level of evidence, 2., Methods: A total of 76 athletes (mean age, 28.7 ± 11.3 years; 35.5% female) with ACL injury were included. Clinical measures of knee function (quadriceps strength, single-legged hop tests, patient-reported outcomes) were assessed after initial impairment resolution (baseline), after 10 additional preoperative or nonoperative rehabilitation sessions (posttraining), and 6 months after ACL reconstruction or nonoperative rehabilitation. Posterior-anterior bent-knee radiographs were completed at 5 years and graded in the medial compartment by use of the Kellgren-Lawrence system. Logistic regression models were used at each of the 3 time points to determine the ability of clinical measures to predict knee OA at 5 years., Results: Of the 76 patients, 9 (11.8%) had knee OA at 5 years. After adjustment for ACL reconstruction compared with nonoperative management, ipsilateral second ACL injuries, and the presence of contralateral knee OA, clinical measures of knee function at posttraining (6-m timed hop, Knee Outcomes Survey-Activities of Daily Living Scale) explained the most variance in posttraumatic OA development at 5 years ( P = .006; ▵ R 2 , 27.5%). The 6-m hop test was the only significant posttraining predictor of OA at 5 years ( P = .023; patients without OA, 96.6% ± 5.4%; patients with OA, 84.9% ± 14.1%). Similar significant group differences in hop scores and subjective knee function were present at baseline. No significant group differences in clinical measures existed at 6 months after ACL reconstruction or nonoperative rehabilitation., Conclusion: Poor performance in single-legged hop tests early after ACL injury but not after reconstruction or nonoperative rehabilitation is associated with the development of radiographic posttraumatic knee OA 5 years after injury. Clinical measures of knee function were most predictive of subsequent OA development following an extended period of rehabilitation early after ACL injury., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: This work was supported by the National Institutes of Health (R37 HD037985, R01 AR048212, P30 GM103333). M.J.A. has received educational support from Horizon Pharma and has received hospitality payments from Arthrex. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Background: Current practice patterns for the management of anterior cruciate ligament (ACL) injury favor surgical reconstruction. However, long-term outcomes may not differ between patients completing operative and nonoperative treatment of ACL injury. Differences in outcomes between operative and nonoperative treatment of patients in the United States is largely unknown, as are outcomes in long-term strength and performance measures., Purpose: To determine if differences exist in 5-year functional and radiographic outcomes between patients completing operative and nonoperative treatment of ACL injury when both groups complete a progressive criterion-based rehabilitation protocol., Study Design: Cohort study; Level of evidence, 2., Methods: From an original group of 144 athletes, 105 participants (mean ± SD age, 34.3 ± 11.4 years) with an acute ACL rupture completed functional testing (quadriceps strength, single-legged hop, and knee joint effusion testing; patient-reported outcomes) and knee radiographs 5 years after ACL reconstruction or completion of nonoperative rehabilitation., Results: At 5 years, patients treated with ACL reconstruction versus rehabilitation alone did not differ in quadriceps strength ( P = .817); performance on single-legged hop tests ( P = .234-.955); activity level ( P = .349-.400); subjective reports of pain, symptoms, activities of daily living, and knee-related quality of life ( P = .090-.941); or presence of knee osteoarthritis ( P = .102-.978). When compared with patients treated nonoperatively, patients treated operatively did report greater global ratings of knee function ( P = .001), and lower fear ( P = .035) at 5 years but were more likely to possess knee joint effusion ( P = .016)., Conclusion: The current findings indicate that favorable outcomes can occur after both operative and nonoperative management approaches with the use of progressive criterion-based rehabilitation. Further study is needed to determine clinical algorithms for identifying the best candidates for surgical versus nonoperative care after ACL injury. These findings provide an opportunity to improve the educational process between patients and clinicians regarding the expected clinical course and long-term outcomes of operative and nonoperative treatment of ACL injuries.

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., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: The Delaware-Oslo ACL Cohort Study is supported by grant R37 HD037985 from the National Institutes of Health. This study was additionally supported by rehabilitation facilities and staff from the Norwegian Sports Medicine Clinic, the University of Delaware Physical Therapy Clinic, and the Delaware Rehabilitation Institute.

Purpose of Review: This review focuses on studies published during July 2001 to August 2017 of exercise as an intervention in knee and hip osteoarthritis, including its influence on an array of patient outcomes., Recent Findings: Studies continue to illustrate the efficacy of exercise in treating and managing osteoarthritis, with current literature more focused on the knee compared with the hip joint. Both traditional (e.g. strength, aerobic, flexibility) and more nontraditional (e.g. yoga, Tai Chi, aquatic) training modes improve patient outcomes related to joint symptoms, mobility, quality of life, psychological health, musculoskeletal properties, body composition, sleep, and fatigue. Exercise that is adequately dosed (e.g. frequency, intensity) and progressive in nature demonstrated the greatest improvements in patient outcomes. Supervised, partially supervised, and nonsupervised interventions can be successful in the treatment of osteoarthritis, but patient preference regarding level of supervision and mode of exercise may be key predictors in exercise adherence and degree of outcome improvement. A topic of increasing interest in osteoarthritis is the supplementary role of behavior training in exercise interventions., Summary: Osteoarthritis is a complex, multifactorial disease that can be successfully managed and treated through exercise, with minimal risk for negative consequences. However, to have greatest impact, appropriate exercise prescription is needed. Efforts to achieve correct exercise doses and mitigate patient nonadherence are needed to lessen the lifelong burden of osteoarthritis.

Study Design Prospective cohort. Background The high risk of second anterior cruciate ligament (ACL) injuries after return to sport highlights the importance of return-to-sport decision making. Objective return-to-sport criteria frequently use limb symmetry indexes (LSIs) to quantify quadriceps strength and hop scores. Whether using the uninvolved limb in LSIs is optimal is unknown. Objectives To evaluate the uninvolved limb as a reference standard for LSIs utilized in return-to-sport testing and its relationship with second ACL injury rates. Methods Seventy athletes completed quadriceps strength and 4 single-leg hop tests before anterior cruciate ligament reconstruction (ACLR) and 6 months after ACLR. Limb symmetry indexes for each test compared involved-limb measures at 6 months to uninvolved-limb measures at 6 months. Estimated preinjury capacity (EPIC) levels for each test compared involved-limb measures at 6 months to uninvolved-limb measures before ACLR. Second ACL injuries were tracked for a minimum follow-up of 2 years after ACLR. Results Forty (57.1%) patients achieved 90% LSIs for quadriceps strength and all hop tests. Only 20 (28.6%) patients met 90% EPIC levels (comparing the involved limb at 6 months after ACLR to the uninvolved limb before ACLR) for quadriceps strength and all hop tests. Twenty-four (34.3%) patients who achieved 90% LSIs for all measures 6 months after ACLR did not achieve 90% EPIC levels for all measures. Estimated preinjury capacity levels were more sensitive than LSIs in predicting second ACL injuries (LSIs, 0.273; 95% confidence interval [CI]: 0.010, 0.566 and EPIC, 0.818; 95% CI: 0.523, 0.949). Conclusion Limb symmetry indexes frequently overestimate knee function after ACLR and may be related to second ACL injury risk. These findings raise concern about whether the variable ACL return-to-sport criteria utilized in current clinical practice are stringent enough to achieve safe and successful return to sport. Level of Evidence Prognosis, 2b. J Orthop Sports Phys Ther 2017;47(5):334-338. Epub 29 Mar 2017. doi:10.2519/jospt.2017.7285.

The objective of the study was to evaluate differences in gait mechanics 5 years after unilateral anterior cruciate ligament reconstruction surgery, for non-osteoarthritic (n = 24) versus osteoarthritic (n = 9) subjects. For the involved knee, the osteoarthritic group demonstrated significantly lower peak knee flexion angles (non-osteoarthritic = 24.3 ± 4.6°, osteoarthritic = 19.1 ± 2.9°, p = 0.01) and peak knee flexion moments (non-osteoarthritic = 5.3 ± 1.2% Body Weight × Height, osteoarthritic = 4.4 ± 1.2% Body Weight × Height, p = 0.05). Differences in peak knee adduction moment approached significance, with a higher magnitude for the osteoarthritic group (non-osteoarthritic = 2.4 ± 0.8% Body Weight × Height, osteoarthritic = 2.9 ± 0.5% Body Weight × Height, p = 0.09). Peak medial compartment joint load was evaluated using electromyography-informed neuromusculoskeletal modeling. Peak medial compartment joint load in the involved knee for the two groups was not different (non-osteoarthritic = 2.4 ± 0.4 Body Weight, osteoarthritic = 2.3 ± 0.6 Body Weight). The results suggest that subjects with dissimilar peak knee moments can have similar peak medial compartment joint load magnitudes. There was no evidence of inter-limb asymmetry for either group. Given the presence of inter-group differences (non-osteoarthritic vs. osteoarthritic) for the involved knee, but an absence of inter-limb asymmetry in either group, it may be necessary to evaluate how symmetry is achieved, over time, and to differentiate between good versus bad inter-limb symmetry, when evaluating knee gait parameters. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:625-633, 2017., (© 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Anterior cruciate ligament (ACL) injury results in altered knee joint mechanics which frequently continue even after ACL reconstruction. The persistence of altered mechanical loading of the knee is of concern due to its likely role in the development of post-traumatic osteoarthritis (OA). Joint contact forces are associated with post-traumatic OA development, but evaluation of factors influencing the magnitude of contact forces after ACL injury is needed to advance current strategies aimed at preventing post-traumatic OA. Therefore, the purpose of this study was to identify predictive factors of knee joint contact forces after ACL reconstruction. Thirty athletes completed standard gait analysis with surface electromyography 6 months after ACL reconstruction. An electromyographic-driven musculoskeletal model was used to estimate joint contact forces. External knee adduction moment was a significant predictor of medial compartment contact forces in both limbs, while vertical ground reaction force and co-contraction only contributed significantly in the uninvolved limb. The large influence of the knee adduction moment on joint contact forces provides mechanistic clues to understanding the mechanical pathway of post-traumatic OA after ACL injury. Statement of Clinical Significance: This study provides critical information in improving the understanding of mechanisms influencing the development of post-traumatic OA after ACL injury. Further work is needed to identify additional driving factors of joint loading in the ACL-injured limb and develop treatment strategies to avert the deleterious consequences of post-traumatic OA. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:651-656, 2017., (© 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Introduction: Knee osteoarthritis (OA) is a degenerative form of arthritis commonly diagnosed in older adults. It presents clinically with patient complaints of pain and impaired function, which are thought to result from cartilage degeneration and other skeletal changes. These changes can by examined radiographically and quantified using the semiquantitative grading scale known as the Kellgren-Lawrence (KL) scale. Currently, no standard training exists for KL grading, which may explain the unsatisfactory reliability of this tool in OA research. Therefore, the objective of this project was to develop a training tutorial for KL grading of knee OA to educate assessors on possible areas of inconsistency in grading., Methods: The tutorial was developed in an e-learning authoring tool, Articulate Presenter. The content focuses on the poor reliability of KL grading, normal anatomy of a knee radiograph, and multiple examples of bony changes within the knee and their relation to different grades of the KL scale. The tutorial was presented to a group of health sciences graduate students at the University of Colorado Denver., Results: Students were able to complete the training and an associated assessment in under an hour and reported improved confidence with assessing radiographic knee OA. Furthermore, they demonstrated favorable inter- and intrarater reliability scores in applying KL grading., Discussion: To our knowledge, this is the first attempt to standardize training in KL grading for knee OA and to examine the effects of this training on reliability., Competing Interests: None to report.

Background: Anterior cruciate ligament (ACL) injury predisposes individuals to early-onset knee joint osteoarthritis (OA). Abnormal joint loading is apparent after ACL injury and reconstruction. The relationship between altered joint biomechanics and the development of knee OA is unknown., Hypothesis: Altered knee joint kinetics and medial compartment contact forces initially after injury and reconstruction are associated with radiographic knee OA 5 years after reconstruction., Study Design: Case-control study; Level of evidence, 3., Methods: Individuals with acute, unilateral ACL injury completed gait analysis before (baseline) and after (posttraining) preoperative rehabilitation and at 6 months, 1 year, and 2 years after reconstruction. Surface electromyographic and knee biomechanical data served as inputs to an electromyographically driven musculoskeletal model to estimate knee joint contact forces. Patients completed radiographic testing 5 years after reconstruction. Differences in knee joint kinetics and contact forces were compared between patients with and those without radiographic knee OA., Results: Patients with OA walked with greater frontal plane interlimb differences than those without OA (nonOA) at baseline (peak knee adduction moment difference: 0.00 ± 0.08 N·m/kg·m [nonOA] vs -0.15 ± 0.09 N·m/kg·m [OA], P = .014; peak knee adduction moment impulse difference: -0.001 ± 0.032 N·m·s/kg·m [nonOA] vs -0.048 ± 0.031 N·m·s/kg·m [OA], P = .042). The involved limb knee adduction moment impulse of the group with osteoarthritis was also lower than that of the group without osteoarthritis at baseline (0.087 ± 0.023 N·m·s/kg·m [nonOA] vs 0.049 ± 0.018 N·m·s/kg·m [OA], P = .023). Significant group differences were absent at posttraining but reemerged 6 months after reconstruction (peak knee adduction moment difference: 0.02 ± 0.04 N·m/kg·m [nonOA] vs -0.06 ± 0.11 N·m/kg·m [OA], P = .043). In addition, the OA group walked with lower peak medial compartment contact forces of the involved limb than did the group without OA at 6 months (2.89 ± 0.52 body weight [nonOA] vs 2.10 ± 0.69 body weight [OA], P = .036)., Conclusion: Patients who had radiographic knee OA 5 years after ACL reconstruction walked with lower knee adduction moments and medial compartment joint contact forces than did those patients without OA early after injury and reconstruction., (© 2015 The Author(s).)