Objective To compare measures of resting cartilage structure and composition in experienced older runners with and without knee osteoarthritis. Design 47 runners (mean (sd) age = 58.0 (8.4) years) with knee osteoarthritis, as well as 27 runners (mean (sd) age = 52.2 (9.7) years) with no radiographic knee osteoarthritis or knee pain participated. Magnetic resonance imaging was used to measure cartilage structure and composition and calculate: volume and thickness, as well as T2 and T1ρ relaxation times, for eight regions of interest. Between group comparisons were examined using analysis of covariance with body mass, years of self-reported running experience, and average weekly running volume over the three months prior to testing included as covariates. Results Few between-group differences were observed. Runners with knee osteoarthritis exhibited less patellar cartilage thickness (mean difference [95% confidence limits]: -0.3 [-0.4, -0.1] mm) and volume (-408 [-736, -79] mm3), but thicker lateral posterior femur cartilage (0.2 [0.0, 0.3] mm), than runners without knee osteoarthritis. Further, runners with knee osteoarthritis generally exhibited longer relaxation times in all regions of interest, though statistical significance was only observed in the lateral posterior femur (T2 relaxation time: 1.8 [0.2, 3.3] ms) and medial posterior femur (T1ρ relaxation time: 2.6 [0.8, 4.4] ms) regions. Conclusions Our findings do not support the notion of widespread cartilage degeneration in the knees of experienced older runners with knee osteoarthritis. Longitudinal research is necessary to examine the longer-term impacts of running on general knee health in runners with and without knee osteoarthritis.

Youth and young adults who experience a traumatic knee injury (i.e., ligament, meniscus, or cartilage injury; intra-articular fracture or dislocation) have a 6-fold elevated risk of early-onset post-traumatic knee osteoarthritis (PTOA), contributing to joint pain and disability for most of their adult lives. This reality represents a daunting personal and societal burden. Currently, there is no proven clinical program that supports individuals at-risk of PTOA self-manage their knee health and reduce their risk, despite evidence that interventions supporting exercise, physical activity, and healthy body composition have promise. This paper describes the development of the Stop OsteoARthritis (SOAR) Program, a multi-component, virtual program that integrates education, behaviour change techniques, tailored progressive exercise and physical activity, self-monitoring, and regular physiotherapist interactions. Guided by the Consolidated Framework for Implementation Research, we describe and reflect on our iterative process for 1) identifying key elements and strategies to self-managing knee health and PTOA risk, 2) developing a program to deliver these elements and strategies, and 3) exploring barriers, facilitators, and opportunities to implementing the program in clinical settings. This information provides a roadmap for developing other programs aimed at reducing the enormous burden of musculoskeletal conditions.

BACKGROUND:Lateral wedge insoles (LWIs) are a non-surgical adjunct treatment for knee osteoarthritis (OA) that has been shown to reduce the knee adduction moment-a biomechanical risk factor for knee OA disease progression. Though worn in one's shoes, little is known of the effects of LWIs use on the foot or ankle. Importantly, it unknown whether their use enhances foot symptoms in people with knee OA and concomitant foot pain, thus questioning the general appropriateness of their use in this subgroup. METHODS:We conducted a pilot, feasibility randomized controlled trial to assess study approaches and general effects of LWIs use in people with knee OA and foot pain. 30 individuals with foot pain and radiographically-confirmed knee OA were randomized to a 12-week intervention using either standalone 6-degree LWIs or LWIs integrated with custom foot and arch support. Feasibility outcomes included: recruitment and retention outcomes; insoles usage, reporting, and comfort; and adverse events. We also examined foot (Foot Function Index pain and difficulty subscales) and knee symptoms (Knee Osteoarthritis Outcomes Severity Score pain and daily function subscales), and gait biomechanics (knee adduction and flexion moment peaks and impulses, ankle/subtalar eversion peaks) before and after the 12-week intervention. RESULTS:All feasibility criteria were met, and no major adverse events were reported. Participants found the insoles moderately comfortable (7/10), and most weeks (278/336, 83%) met the acceptable 30 min per day wear time threshold. Though no statistical comparisons were made, changes in clinical and biomechanical outcomes were consistent with previous research; specifically, trends toward improvement in knee pain and function, as well as knee adduction moment magnitudes, in both groups. CONCLUSION:Lateral wedge insoles, with or without support, appear safe for people with knee OA and concomitant foot pain. Given positive feasibility and efficacy observations, future research in this area is warranted.

OBJECTIVE: To compare injured and uninjured limb knee extensor and flexor peak torque between youth who experienced a sport-related, traumatic knee joint injury and comparable uninjured youth, at baseline (≤4 months of injury) and semiannually for 2 years. Differences by injury type and sex were also explored. DESIGN: Prospective cohort study. METHODS: Bilateral knee extensor and flexor concentric isokinetic peak torque at 90° per second was assessed semiannually in 186 youth (106 injured, 80 controls) for 2 years. Between-group differences in strength over time were estimated with generalized estimating equations (95% confidence interval [CI]). Confounding was controlled using inverse probability weighting. Strength differences between those with anterior cruciate ligament (ACL) tears and those with non-ACL tear injuries as well as between male and female participants were explored. RESULTS: Compared to uninjured controls, injured limb knee extensor strength was lowest at baseline (-37.1 Nm; 95% CI, -45.3 to -28.9) and 6-month follow-up (-13.3 Nm; 95% CI, -20.4 to -6.2), with minimal strength gain beyond the 12-month follow-up (1.7 Nm; 95% CI, -14.3 to 17.6). Knee flexor strength of the injured limb was lowest at baseline (-24.6 Nm; 95% CI, -31.5 to -17.8), and there was minimal strength gain beyond 6 months (2.3 Nm; 95% CI, -7.7 to 12.3). The average residual deficit was similar to the knee extensors (10% to 11%) at 24 months. Exploratory analysis suggested no difference based on injury type or sex. CONCLUSION: Injured limb knee extensor and flexor weakness was present after different youth sport-related knee joint injuries. Strength deficits peaked early after injury, improved over time, and plateaued after 12 months, with lingering deficits at 24 months. Thigh muscle strength trajectory was similar across injury types and sex. J Orthop Sports Phys Ther 2025;55(2):1-11. Epub 20 December 2024. doi:10.2519/jospt.2024.12663.

People who tear their anterior cruciate ligament and have reconstruction surgery (ACLR) are at elevated risk of inactivity, obesity, and early-onset knee osteoarthritis. Consensus recommendations to prevent post-traumatic knee osteoarthritis include person-centered education and exercise-based treatments. The effectiveness of these recommendations is unknown. This study will assess if a digital education and exercise therapy intervention is superior to minimal intervention for improving knee-related symptoms, function, and quality of life in young people after ACLR. The Stop OsteoARthritis (SOAR) study is a parallel, two-arm, assessor-blinded, superiority, hybrid effectiveness-implementation type 1 randomized controlled trial. After baseline testing, 166 participants aged 16–35 years, 9–36 months past, a first-time ACLR with ongoing symptoms will be randomly allocated to one of two treatment groups (1:1 ratio, stratified by sex). Ongoing symptoms will be defined as not meeting a Patient Acceptable Symptom State (PASS) on the averaged Knee injury and Osteoarthritis Outcome Score pain, symptoms function in sport and recreation, and quality-of-life subscales (KOOS4 < 79). Participants randomized to the experimental intervention will receive a digital (remote videoconferencing) 6-month program of group-based learning, individualized weekly home-based exercise therapy and physical activity program with tracking, and 1:1 physiotherapist-guided counseling. Participants randomized to the minimal intervention control group will receive an educational recording, best-practice guide for ACLR rehabilitation, one videoconferencing session, and tracking. The primary effectiveness outcome is the between-group difference in KOOS4 change from baseline to 6-months, with secondary endpoints at 12- and 24months. Secondary effectiveness outcomes include differences in the change of individual KOOS subscale scores, proportions of participants achieving KOOS subscale PASS scores, perceived self-management, and MRI features of knee OA. We will also assess secondary implementation (perceived barriers and facilitators of SOAR delivery), secondary efficiency (incremental cost-utility ratio), and exploratory outcomes. Missing data will be imputed and blinded intention-to-treat analyses performed. By assessing the effect, implementation, and efficiency of a digital education and exercise-based intervention designed to improve the knee health of young people at increased risk of knee osteoarthritis, this study will provide a basis for future scale-up to help curb the mounting burden of osteoarthritis. ClinicalTrials.gov NCT06195423. Registered on December 22, 2023.

BACKGROUND:Assess the association between changes in injured leg knee extension and flexion strength (peak torque) and self-reported and performance-based measures of leg function after a variety of youth sport-related, time-loss knee injuries. HYPOTHESIS:There will be a relationship between changes in knee muscle strength and changes in measures of leg function in youth after a sport-related knee injury. STUDY DESIGN:Prospective cohort study. LEVEL OF EVIDENCE:Level 2. METHODS:This was a secondary analysis of the Alberta Youth Prevention of Early Osteoarthritis (PrEOA) Cohort study (Edmonton) that included youth (11-19 years old) who had experienced a medical attention, time-loss, sport-related knee injury in the previous 4 months. Injured leg knee extensor and flexor concentric peak torque (isokinetic; 90 deg/s), triple hop distance, modified Y-balance test (YBT), and Knee injury and Osteoarthritis Outcome Score Sport subscale (KOOSsport) were assessed at baseline (≤4 months postinjury) and 6 and 12 months later. Adjusted associations between 6- and 12-month change in strength and functional measures were assessed using multivariable regression (95% CI). RESULTS:Based on data from 106 participants (16.2 ± 1.8 years old), a 1 Nm increase in knee extensor strength (6-12 months) was associated with a 0.9 cm (95% CI, -0.5, 2.3) increase in hop distance. Similarly, every 1 Nm increase in knee flexor strength (6-12 months) was associated with a 0.3 cm (95% CI, -1.1, 1.7) increase in hop distance. Across other models, a 1 Nm increase in extensor or flexor strength was associated with a 0- to 0.3-point increase in KOOSsport score. CONCLUSION:There was minimal-to-no longitudinal relationship between changes in knee extensor or flexor strength and changes in triple hop or YBT performance, or self-reported function within the first year after a youth sport-related knee injury.

Abstract Background Familial hypercholesterolemia (FH) is a genetic condition that affects cholesterol metabolism, resulting in life-long elevated serum levels of low-density lipoprotein cholesterol. Systemically elevated cholesterol levels are associated with the onset of tendon injury and potentially lead to impaired mechanical properties. Applying a cross-sectional design, we examined whether FH patients present with altered Achilles biomechanics compared to healthy controls and conducted correlational analyses to determine the relationship between Achilles tendon biomechanics and tendon lipid or water content. Methods Patients with FH (n = 33) and healthy controls (n = 31) were recruited from the Greater Vancouver area. Achilles cross sectional area, thickness, lipid and water content was determined using Dixon method magnetic resonance imaging (3.0T). Achilles mechanical properties were determined using synchronized dynamometry, motion capture, ultrasound and electromyography during ramped maximal voluntary isometric contractions, and stiffness and Young’s modulus calculated. Between group differences were assessed with independent t-tests or Mann-Whitney U tests and Pearson’s r or Spearman’s ρ were employed for correlational analyses. Sensitivity analysis was conducted on FH patients diagnosed with Achilles xanthoma and the remaining FH patients. Results FH patients had significantly elevated Achilles total water content (p = 0.006), cross-sectional area (p = 0.006), and thickness (p = 0.019). No between-group differences were observed in any of the biomechanical parameters. In patients with FH there were significant positive relationships between tendon lipid or water content and tendon strain (ρ = 0.35, p = 0.046; r = 0.42, p = 0.02, respectively). No significant relationships were observed in control participants. In patients with FH, increased tendon cross-sectional area was associated with reduced stiffness (r=-0.371, p = 0.033) and increased strain (r = 0.48, p = 0.005). The presence of xanthoma was associated with increased Achilles dimensions (p < 0.05), total water content (p = 0.03), strain (p = 0.029), and decreased Young’s modulus (p = 0.001). Conclusion Increased Achilles lipid and water content is associated with increased tendon strain in people with FH and the presence of xanthoma might indicate altered tendon mechanics. This study holds relevance for individuals with hypercholesteremia, as best management practices advocate for physical activity as part of a healthy lifestyle.

The purpose of this study was to compare quadriceps morphology between legs and individuals with a first-time anterior cruciate ligament (ACL) tear and uninjured controls. This was an exploratory cross-sectional study. We enrolled participants who were aged 19-35 years, and 6-60 months after a first-time ACL tear as well as uninjured controls. Participants attended two sessions separated by a minimum of 7 days. Bilateral knee extensor concentric and eccentric strength and rate of torque development (RTD) were assessed at the first session, and bilateral vastus lateralis muscle biopsies were obtained at the second. Muscle fiber-type specific cross-sectional area (fCSA), fiber-type proportions, and extracellular matrix area were calculated. Between-limb and between-group differences were estimated using mixed-effects regression. 41 of 47 (87%) participants completed the study (n = 21 ACL, n = 20 control). ACL group participants were a median (range) of 23 months from injury, and 78% had undergone an ACL reconstruction. Uninjured group participants had greater knee extensor concentric strength (-39.3 Nm; 95% CI: -54.2, -20.5), eccentric strength (-30.2 Nm; 95% CI: -53.4, -11.6), and RTD (-0.16 Nm/ms; 95% CI: -0.33, -0.04). No between-group or between-limb differences in muscle fiber-type specific fCSA, fiber-type proportions, or extracellular matrix area were observed. Despite deficits in knee extensor muscle performance, no difference in vastus lateralis fiber-type specific CSA, fiber-type proportion, or extracellular matrix area was detected between individuals 6-60 months after an ACL tear and uninjured controls.

OBJECTIVES: Anterior cruciate ligament (ACL) tears and subsequent reconstruction surgery are associated with a recalcitrant decline in quadriceps muscles’ performance, which can persist for decades, contributing to impaired function, elevated osteoarthritis risk, and poor quality of life. Little is known about why this decline occurs, or if it can be prevented. One important component of quadriceps muscles’ performance that may be impacted by an ACL tear or ACL reconstruction (ACLR) surgery is the ability to rapidly contract and produce force in response to neuromuscular activation, known as explosive neuromuscular performance. This study will compare quadriceps muscles explosive neuromuscular performance and its determinants between injured and uninjured legs of individuals 9–48 months after primary ACLR. DESIGN: Cross-sectional study METHODS: This cross-sectional study will include 48 individuals aged 18–40 years, 9–48 months past a first-time ACLR performed within 12 months of an ACL tear. The primary outcome is isometric knee extension torque (Nm; computerized dynamometry, 90° flexion) at 100 ms after first electrical onset of any quadriceps muscle (electromyography). Secondary outcomes include rate of knee extension torque development (computerized dynamometry), electromechanical delay (electromyography), patellar tendon stiffness (myotonometry), and patellar tendon cross-sectional area (ultrasound imaging). A mixed-effects regression model (95% confidence interval) will assess between-group differences for all outcomes, adjusted for ACL graft harvest site and sex. The association between explosive neuromuscular performance and secondary outcomes will be explored as appropriate. DISCUSSION: Improved understanding of quadriceps muscles explosive neuromuscular performance and its determinants could shed light on mechanisms that underlie the decline in quadriceps muscles’ performance seen after ACL reconstruction and inform treatment targets. JOSPT Methods 2025;1(1):8-16. Epub 25 November 2024. doi:10.2519/josptmethods.2024.0102

Purpose (the aim of the study): All types of traumatic knee injuries increase the risk of post-traumatic knee osteoarthritis (PTOA). Modifiable factors, particularly knee extensor (KE) and knee flexor (KF) weakness, might further amplify this risk. Persistent KE and KF muscle weakness are well documented after anterior cruciate ligament (ACL) tears treated with ACL reconstruction (ACLR). However, it is unclear if KE and KF strength are also affected by other types of traumatic knee joint injuries (e.g., meniscal tears) and if the magnitude of weakness differs by injury type.

Objective:To explore clinical practice patterns of physical therapists (PTs) who treat people with Achilles tendinopathy (AT), and identify perceived barriers and facilitators for prescribing and engaging with therapeutic exercise among PTs and people with AT.Methods:Two cross-sectional surveys were electronically distributed between November 2021 and May 2022; one survey was designed for PTs while the second was for people with AT. Survey respondents answered questions regarding their physical therapy training and current practice (PTs), injury history and management (people with AT), and perceived barriers and facilitators (PTs and people with AT).Results:341 PTs and 74 people with AT completed the surveys. In alignment with clinical practice guidelines, more than 94% of PTs surveyed (97% of whom had some form of advanced musculoskeletal training) prioritise patient education and therapeutic exercise. Patient compliance, patient knowledge, and the slow nature of recovery were barriers to prescribing therapeutic exercise reported by PTs, while time, physical resources, and a perceived lack of short-term treatment effectiveness were barriers for people with AT.Conclusions:Consistent with clinical practice guidelines, PTs with advanced training reported prioritising therapeutic exercise and education for managing AT. However, both PTs and people with AT identified many barriers to prescribing or engaging with therapeutic exercise. By addressing misconceptions about the time burden and ineffectiveness of exercise, and by overcoming access issues to exercise space and equipment, PTs may be able to improve intervention adherence and subsequently outcomes for people with AT.

Purpose (the aim of the study): We performed a systematic review with individual participant data (IPD) meta-analysis (MA) of randomized controlled trials (RCTs) investigating mechanical devices to treat knee OA. We aimed to identify subgroup characteristics that moderate treatment effects.

Purpose (the aim of the study): Assessment of walking gait biomechanics is an important is an important strategy to monitor the status and progression of knee osteoarthritis (KOA) and to understand its pathomechanics. Numerous studies have linked several gait characteristics – including the external knee adduction moment (KAM) – to clinically-relevant outcomes such as symptoms, disease progression, and disease severity, while fewer studies have examined differences in these gait characteristics between males and females.

OBJECTIVE:The aim of this study was to comprehensively examine and summarize the available in vitro evidence regarding the relationship between mechanical stimulation and biomarkers of collagen synthesis in human-derived tendon cells. METHODS:Systematic review with narrative analyses and risk of bias assessment guided by the Health Assessment and Translation tool. The electronic databases MEDLINE (Ovid), EMBASE (Ovid), CENTRAL (Ovid) and COMPENDEX (Engineering Village) were systematically searched from inception to 3 August 2023. Inclusion criteria encompassed English language, original experimental, or quasi-experimental in vitro publications that subjected human tendon cells to mechanical stimulation, with collagen synthesis (total collagen, type I, III, V, XI, XII, and XIV) and related biomarkers (matrix metalloproteinases, transforming growth factor β, scleraxis, basic fibroblast growth factor) as outcomes. RESULTS:Twenty-one publications were included. A pervasive definite high risk of bias was evident in all included studies. Owing to incomplete outcome reporting and heterogeneity in mechanical stimulation protocols, planned meta-analyses were unfeasible. Reviewed data suggested that human tendon cells respond to mechanical stimulation with increased synthesis of collagen (e.g., COL1A1, procollagen, total soluble collagen, etc.), scleraxis and several matrix metalloproteinases. Results also indicate that mechanical stimulation dose magnitude may influence synthesis in several biomarkers. CONCLUSIONS:A limited number of studies, unfortunately characterized by a definite high risk of bias, suggest that in vitro mechanical stimulation primarily increases type I collagen synthesis by human tendon cells. Findings from this systematic review provide researchers and clinicians with biological evidence concerning the possible beneficial influence of exercise and loading on cellular-level tendon adaptation.

OBJECTIVE:Assess the efficacy of an 8-week virtual, physiotherapist (PT)-guided knee health program (Stop OsteoARthritis (SOAR)) to improve knee extensor strength in individuals at risk of post-traumatic knee osteoarthritis (PTOA). METHOD:In this superiority, randomized delayed-control trial, persons aged 16-35 years, 1-4 years after a self-reported knee joint injury were randomly assigned (1:1) to receive the SOAR program immediately (experimental group) or after a 9-week delay (control group). SOAR includes 1) one-time Knee Camp (virtual PT-guided group education, knee assessment, 1:1 exercise and physical activity (PA) goal-setting); 2) Weekly personalized home-based exercise and PA program with tracking; 3) Weekly 1:1 PT counseling (virtual). The primary outcome was a change in isokinetic knee extensor strength (baseline to 9-weeks). Additional outcomes included change in self-reported knee-related quality-of-life (QOL), self-efficacy, self-management and kinesiophobia, and PA (accelerometer) at 9 and 18-weeks. Linear regression models estimated the effect of the 8-week intervention at the primary endpoint (9-week). RESULTS:49 of 54 randomized participants completed the study (91%). Participants were a mean ± standard deviation age of 27 ± 5.0 years, and 2.4 ± 0.9 years post-injury. No mean between group differences for the primary (0.05; 95% confidence interval (CI): -0.10, 0.19) or other outcomes were seen at 9 weeks except for greater improvements in perceived self-management (Partner in Health Scale; 11.3/96, 95%CI: 5.5, 17.1) and kinesiophobia (Tampa Scale of Kinesiophobia; -4.4/33, 95%CI: -7.0, -1.8). CONCLUSION:For active persons with elevated risk of PTOA, an 8-week SOAR program did not change knee-related strength, QOL, self-efficacy, or PA, on average, but may benefit the ability to self-manage knee health and kinesiophobia.

Pain changes how we move, but it is often confounded by other factors due to disease or injury. Experimental pain offers an opportunity to isolate the independent effect of pain on movement. We used cutaneous electrical stimulation to induce experimental knee pain during locomotion to study the short-term motor adaptions to pain. While other models of experimental pain have been used in locomotion, they lack the ability to modulate pain in real-time. Twelve healthy adults completed the single data collection session where they experienced six pain intensity conditions (0.5, 1, 2, 3, 4, 5 out of 10) and two pain delivery modes (tonic and phasic). Electrodes were placed over the lateral infrapatellar fat pad and medial tibial condyle to deliver the 10 Hz pure sinusoid via a constant current electrical stimulator. Pain intensity was calibrated prior to each walking bout based on the target intensity and was recorded using an 11-point numerical rating scale. Knee joint angles and moments were recorded over the walking bouts and summarized in waveform and discrete outcomes to be compared with baseline walking. Knee joint angles changed during the swing phase of gait, with higher pain intensities resulting in greater knee flexion angles. Minimal changes in joint moments were observed but there was a consistent pattern of decreasing joint stiffness with increasing pain intensity. Habituation was limited across the 30-90 second walking bouts and the electrical current needed to deliver the target pain intensities showed a positive linear relationship. Experimental knee pain shows subtle biomechanical changes and favourable habituation patterns over short walking bouts. Further exploration of this model is needed in real-world walking conditions and over longer timeframes to quantify motor adaptations.

Purpose (the aim of the study): Altered lower extremity biomechanics during walking are a key feature of symptomatic and structural knee osteoarthritis (OA). A number of these biomechanical variables have been associated with pain and progression of knee OA. There is a common perception that running is not safe for arthritic knees because of the high joint loads experienced, yet only one study has reported the biomechanics of running in this population. The study reported significantly greater tibiofemoral joint contact forces in the OA group compared to healthy controls, but no differences in the knee adduction moment.

Imbalanced joint load distribution across the tibiofemoral surface is a risk factor for osteoarthritic changes to this joint. Lateral wedge insoles, with and without arch support, are a form of biomechanical intervention that can redistribute tibiofemoral joint load, as estimated by external measures of knee load. The objective of this study was to examine the effect of these insoles on the internal joint contact characteristics of osteoarthritic knees during weightbearing. Fifteen adults with tibiofemoral osteoarthritis underwent magnetic resonance imaging of the affected knee, while standing under 3 insole conditions: flat control, lateral wedge alone, and lateral wedge with arch support. Images were processed, and the surface area and centroid location of joint contact were quantified separately for the medial and lateral tibiofemoral compartments. Medial contact surface area was increased with the 2 lateral wedge conditions compared with the control (P ≤ .012). A more anterior contact centroid was observed in the medial compartment in the lateral wedge with arch support compared with the lateral wedge alone (P = .009). Significant changes in lateral compartment joint contact outcomes were not observed. These findings represent early insights into how loading at the tibiofemoral interface may be altered by lateral wedge insoles as a potential intervention for knee osteoarthritis.