A systems view of risk factors for knee osteoarthritis reveals insights into the pathogenesis of the disease

Effects of human umbilical cord mesenchymal stem cell-derived exosomes in the rat osteoarthritis models

Mesenchymal stem cells (MSCs) offer great potential for treatment of osteoarthritis (OA) by promoting articular cartilage regeneration via paracrine secretion of exosomes; however, the underlying mechanisms are not fully understood. This study aimed to explore the therapeutic effects of exosomes secreted by human umbilical cord-derived MSCs (hUC-MSCs) in rat models of OA and reveal the underlying mechanisms. UC-MSCs and UC-MSC-exosomes were prepared and identified by transmission electron microscopy and flow cytometry. IL-1β-induced OA chondrocytes and the operation and collagenase-induced OA rat models were established. The results of micro-computed tomography, histology, and immunohistochemistry showed that UC-MSC-exosomes promoted cartilage regeneration in OA rats. ELISA results showed that the levels of synovial fluid cytokines, TNF-α, IL-1β, and IL-6, were lower in exosome therapy group than control group in both OA rat models. Exosome treatment significantly downregulated the expression of MMP-13 and ADAMTS-5 in chondrocytes stimulated by IL-1β, and upregulated collagen II expression. These findings suggest that hUC-MSC-exosomes offer a promising option for the therapy for OA.

Speed-dependent modulations of muscle modules in the gait of people with radiographical and asymptomatic knee osteoarthritis and elderly controls: Case-control pilot study

This study investigates the muscle modules involved in the increase of walking speed in radiographical and asymptomatic knee osteoarthritis (KOA) patients using tensor decomposition. The human body possesses redundancy, which is the property to achieve desired movements with more degrees of freedom than necessary. The muscle module hypothesis is a proposed solution to this redundancy. While previous studies have examined the pathological muscle activity modulations in musculoskeletal diseases such as KOA, they have focused on single muscles rather than muscle modules. Moreover, most studies have only examined the gait of KOA patients at a single speed, leaving the way in which gait speed affects gait parameters in KOA patients unclear. Assessing this influence is crucial for determining appropriate gait speed and understanding why preferred gait speed decreases in KOA patients. In this study, we apply tensor decomposition to muscle activity data to extract muscle modules in KOA patients and elderly controls during walking at different speeds. We found a muscle module comprising hip adductors and back muscles that activate bimodally in a gait cycle, specific to KOA patients when they increase their walking speed. These findings may provide valuable insights for rehabilitation for KOA patients.

Osteoarthritic Tibiofemoral Joint Contact Characteristics During Weightbearing With Arch-Supported and Standalone Lateral Wedge Insoles

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.

Elevated proinflammatory cytokines in response to mechanical stimulus are associated with reduced knee loading 2 years after anterior cruciate ligament reconstruction

BACKGROUND

The aim of this study was to test the hypothesis that proinflammatory cytokines correlate with knee loading mechanics during gait following a mechanical walking stimulus in subjects 2 years after anterior cruciate ligament reconstruction. Elevated systemic levels of proinflammatory cytokines can be sustained for years after injury. Considering roughly 50% of these patients progress to Osteoarthritis 10-15 years after injury, a better understanding of the role of proinflammatory cytokines such as tumor necrosis factor-α and Interleukin-1β on Osteoarthritis risk is needed.

METHODS

Serum proinflammatory cytokines concentrations were measured in 21 subjects 2 years after unilateral ACLR from blood drawn at rest and 3.5 h after 30 min of walking. An optoelectronic system and a force plate measured subjects' knee kinetics. Correlations were tested between inflammatory marker response and knee extension and knee adduction moments.

FINDINGS

Changes in proinflammatory cytokines due to mechanical stimulus were correlated (R = 0.86) and showed substantial variation between subjects in both cytokines at 3.5 h post-walk. Knee loading correlated with 3.5-h changes in tumor necrosis factor-α concentration (Knee extension moment: R = -0.5, Knee adduction moment: R = -0.5) and Interleukin-1β concentration (Knee extension moment: R = -0.44). However, no significant changes in concentrations were observed in tumor necrosis factor-α and Interleukin-1β when comparing baseline and post walking stimulus conditions.

INTERPRETATION

The significant associations between changes in serum proinflammatory markers following a mechanical stimulus and gait metrics in subjects at risk for developing Osteoarthritis underscore the importance of investigating the interaction between biomarkers and biomechanical factors in Osteoarthritis development.

Reproducibility of Quantitative Double-Echo Steady-State T2 Mapping of Knee Cartilage

BACKGROUND

Cartilage T2 can detect joints at risk of developing osteoarthritis. The quantitative double-echo steady state (qDESS) sequence is attractive for knee cartilage T2 mapping because of its acquisition time of under 5 minutes. Understanding the reproducibility errors associated with qDESS T2 is essential to profiling the technical performance of this biomarker.

PURPOSE

To examine the combined acquisition and segmentation reproducibility of knee cartilage qDESS T2 using two different regional analysis schemes: 1) manual segmentation of subregions loaded during common activities and 2) automatic subregional segmentation.

STUDY TYPE

Prospective.

SUBJECTS

11 uninjured participants (age: 28 ± 3 years; 8 (73%) female).

FIELD STRENGTH/SEQUENCE

3-T, qDESS.

ASSESSMENT

Test-retest T2 maps were acquired twice on the same day and with a 1-week interval between scans. For each acquisition, average cartilage T2 was calculated in four manually segmented regions encompassing tibiofemoral contact areas during common activities and 12 automatically segmented regions from the deep-learning open-source framework for musculoskeletal MRI analysis (DOSMA) encompassing medial and lateral anterior, central, and posterior tibiofemoral regions. Test-retest T2 values from matching regions were used to evaluate reproducibility.

STATISTICAL TESTS

Coefficients of variation (%CV), root-mean-square-average-CV (%RMSA-CV), and intraclass correlation coefficients (ICCs) assessed test-retest T2 reproducibility. The median of test-retest standard deviations was used for T2 precision. Bland-Altman (BA) analyses examined test-retest biases. The smallest detectable difference (SDD) was defined as the BA limit of agreement of largest magnitude. Significance was accepted for P < 0.05.

RESULTS

All cartilage regions across both segmentation schemes demonstrated intraday and interday qDESS T2 CVs and RMSA-CVs of ≤5%. T2 ICC values >0.75 were observed in the majority of regions but were more variable in interday tibial comparisons. Test-retest T2 precision was <1.3 msec. The T2 SDD was 3.8 msec.

DATA CONCLUSION

Excellent CV and RMSA-CV reproducibility may suggest that qDESS T2 increases or decreases >5% (3.8 msec) could represent changes to cartilage composition.

LEVEL OF EVIDENCE: 2

TECHNICAL EFFICACY

Stage 2.

Load carriage changes tibiofemoral arthrokinematics during ambulatory tasks in recruit-aged women

The introduction of women into U.S. military ground close combat roles requires research into sex-specific effects of military training and operational activities. Knee osteoarthritis is prevalent among military service members; its progression has been linked to occupational tasks such as load carriage. Analyzing tibiofemoral arthrokinematics during load carriage is important to understand potentially injurious motion and osteoarthritis progression. The study purpose was to identify effects of load carriage on knee arthrokinematics during walking and running in recruit-aged women. Twelve healthy recruit-aged women walked and ran while unloaded (bodyweight [BW]) and carrying additional + 25%BW and + 45%BW. Using dynamic biplane radiography and subject-specific bone models, tibiofemoral arthrokinematics, subchondral joint space and center of closest contact location between subchondral bone surfaces were analyzed over 0-30% stance (separate one-way repeated measures analysis of variance, load by locomotion). While walking, medial compartment contact location was 5% (~ 1.6 mm) more medial for BW than + 45%BW at foot strike (p = 0.03). While running, medial compartment contact location was 4% (~ 1.3 mm) more lateral during BW than + 25%BW at 30% stance (p = 0.04). Internal rotation was greater at + 45%BW compared to + 25%BW (p < 0.01) at 30% stance. Carried load affects tibiofemoral arthrokinematics in recruit-aged women. Prolonged load carriage could increase the risk of degenerative joint injury in physically active women.

Unbalanced Medial-to-Lateral Knee Muscle Co-Contractions are Associated with Medial Tibiofemoral Underloading during Gait Three Months after Anterior Cruciate Ligament Reconstruction

Altered medial/lateral knee muscle co-contraction (measure by co-contraction indices, CCI) occurs during gait early after anterior cruciate ligament reconstruction (ACLR). Changes in peak medial compartment forces (pMCF) are also observed early after ACLR and are linked to the development of knee osteoarthritis. We do not know if imbalanced co-contraction is associated with these alterations in knee load. The purpose of this study was to evaluate the association between pMCF and the CCIs of medial/lateral knee muscle pairs during walking three months after ACLR. Bilateral knee gait mechanics and electromyography (EMG) data were collected from 44 participants 3 months following surgery. CCIs of six muscle pairs and medial-to-lateral (M:L) CCIs ratios were calculated during the weight acceptance interval. Bilateral pMCFs were calculated using a subject-based neuromusculoskeletal model. Based on interlimb pMCF symmetry, participants were divided into three groups: symmetric loaders, underloaders, and overloaders. A 2 × 3 (limb × group) ANOVA was used to compare CCIs between limbs in all groups. A partial Spearman's test was performed to examine the association between CCIs ratios and pMCF. The CCIs of the vastus lateralis-lateral gastrocnemius muscle pair was higher in the involved limb of underloaders (vs. the uninvolved limb and vs. the involved limb of symmetric loaders). The ratio of M:L CCIs was significantly lower (more lateral CCIs) in the involved limb, which was associated with lower pMCF. These results suggest that individuals early after ACLR who walk with higher CCIs of lateral knee musculature (vs. medial), have medial tibiofemoral underloading.

Current status and influencing factors of self-management in knee joint discomfort among middle-aged and elderly people: a cross-sectional study

BACKGROUND

This study aims to identify the current status and factors influencing self-management of knee discomfort in middle-aged and elderly people in China.

METHODS

A stratified multistage cluster sampling method was used to select participants from communities in China from January 15 to May 31, 2020. A cross-sectional survey was conducted using the general information questionnaire and the Knee Joint Discomfort Self-management Scale. Univariate analysis and a generalized linear model were used to analyze the factors influencing self-management.

RESULTS

The prevalence of knee discomfort was 77%. Moderate to severe discomfort accounted for 30.5%. The average item score of self-management in 9640 participants was 1.98 ± 0.76. The highest and lowest levels were: 'daily life management' and 'information management'. Gender, ethnicity, education level, economic source, chronic disease, knee pain in the past month, and the degree of self-reported knee discomfort were significant predictors of self-management.

CONCLUSION

The self-management of knee discomfort in middle-aged and elderly people is poor, and the degree of discomfort is a significant predictor. Healthcare providers should consider socioeconomic demographic and clinical characteristics to help these individuals improve their self-management skills. Attention should also be given to improving their ability to access health information and making them aware of disease risks.

Remotely delivered, individualized, and self-directed gait modification for knee osteoarthritis: A pilot trial

BACKGROUND

Gait modification interventions have reported variable results and relied on in-person biofeedback limiting clinical accessibility. Our objective was to assess a remotely delivered and self-directed gait modification for knee osteoarthritis.

METHODS

This was an unblinded, 2-arm, delayed control, randomized pilot trial (NCT04683913). Adults aged ≥50 years with symptomatic medial knee osteoarthritis were randomized to an immediate group (Week 0: Baseline, Intervention; Week 6: Follow-up, Week 10: Retention) or delayed group (Week 0: Baseline, Wait Period, Week 6: Secondary Baseline, Intervention, Week 12: Follow-up, Week 16: Retention). Participants practiced modifying their foot progression angle "as much as was comfortable" while receiving support via weekly telerehabilitation appointments and remote monitoring with an instrumented shoe. Primary outcomes included participation, foot progression angle modification magnitude, confidence, difficulty, and satisfaction while secondary outcomes included symptoms and knee biomechanics during gait.

RESULTS

We screened 134 people and randomized 20. There was no loss to follow up and 100% attendance at the telerehabilitation appointments. By follow up, participants reported high confidence (8.6/10), low difficulty (2.0/10), and satisfaction (75%) with the intervention and no significant adverse events. Foot progression angle was modified by 11.4° ± 5.6, which was significantly different (p < 0.001, η²_g = 0.8) when compared between groups. No other between-group differences were significant, while several significant pre-post improvements in pain (d = 0.6, p = 0.006) and knee moments (d = 0.6, p = 0.01) were observed.

INTERPRETATION

A personalized, self-directed gait modification supported with telerehabilitation is feasible, and the preliminary effects on symptoms and biomechanics align with past trials. A larger trial is warranted to evaluate efficacy.

The Effects of Different Management Strategies or Rehabilitation Approaches on Knee Joint Structural and Molecular Biomarkers Following Traumatic Knee Injury: A Systematic Review of Randomized Controlled Trials for the OPTIKNEE Consensus

OBJECTIVE: To summarize the effectiveness of management strategies and rehabilitation approaches for knee joint structural and molecular biomarker outcomes following anterior cruciate ligament (ACL) and/or meniscal tear. DESIGN: Intervention systematic review. LITERATURE SEARCH: We searched the MEDLINE, Embase, CINAHL, CENTRAL, and SPORTDiscus databases from their inception up to November 3, 2021. STUDY SELECTION CRITERIA: We included randomized controlled trials (RCTs) investigating the effectiveness of management strategies or rehabilitation approaches for structural/molecular biomarkers of knee joint health following ACL and/or meniscal tear. DATA SYNTHESIS: We included 5 RCTs (9 papers) with primary ACL tear (n = 365). Two RCTs compared initial management strategies (rehabilitation plus early vs optional delayed ACL surgery), reporting on structural biomarkers (radiographic osteoarthritis, cartilage thickness, meniscal damage) in 5 papers and molecular biomarkers (inflammation, cartilage turnover) in 1 paper. Three RCTs compared different post-ACL reconstruction (ACLR) rehabilitation approaches (high vs low intensity plyometric exercises, accelerated vs nonaccelerated rehabilitation, continuous passive vs active motion), reporting on structural biomarkers (joint space narrowing) in 1 paper and molecular biomarkers (inflammation, cartilage turnover) in 2 papers. RESULTS: There were no differences in structural or molecular biomarkers between post-ACLR rehabilitation approaches. One RCT comparing initial management strategies demonstrated that rehabilitation plus early ACLR was associated with greater patellofemoral cartilage thinning, elevated inflammatory cytokine response, and reduced incidence of medial meniscal damage over 5 years compared to rehabilitation with no/delayed ACLR. CONCLUSION: Very low-certainty evidence suggests that different initial management strategies (rehabilitation plus early vs optional delayed ACL surgery) but not postoperative rehabilitation approaches may influence the incidence of meniscal damage, patellofemoral cartilage loss and cytokine concentrations over 5 years post-ACL tear. J Orthop Sports Phys Ther 2023;53(4):1-22. Epub: 20 February 2023. doi:10.2519/jospt.2023.11576.

Changes in biomechanics, strength, physical function, and daily steps after extended-release corticosteroid injections in knee osteoarthritis: a responder analysis

INTRODUCTION/OBJECTIVE

To determine changes in gait biomechanics, quadricep strength, physical function, and daily steps after an extended-release corticosteroid knee injection at 4 and 8 weeks post-injection in individuals with knee osteoarthritis as well as between responders and non-responders based on changes in self-reported knee function.

METHOD

The single-arm, clinical trial included three study visits (baseline, 4 weeks, and 8 weeks post-injection), where participants received an extended-release corticosteroid injection following the baseline visit. Time-normalized vertical ground reaction force (vGRF), knee flexion angle (KFA), knee abduction moment (KAM), and knee extension moment (KEM) waveforms throughout stance were collected during gait biomechanical assessments. Participants also completed quadricep strength, physical function (chair-stand, stair-climb, 20-m fast-paced walk) testing, and free-living daily step assessment for 7 days following each visit.

RESULTS

All participants demonstrated increased KFA excursion (i.e., greater knee extension angle at heel strike and KFA at toe-off), increased KEM during early stance, improved physical function (all p < 0.001), and increased quadricep strength at 4 and 8 weeks. KAM increased throughout most of stance at 4 and 8 weeks post-injection (p < 0.001) but appears to be driven by gait changes in non-responders. Non-responders demonstrated lesser vGRF during late stance and lesser KEM and KFA throughout stance compared to responders at baseline.

CONCLUSIONS

Extended-release corticosteroid injections demonstrated short-term improvements in gait biomechanics, quadricep strength, and physical function for up to 4 weeks. However, non-responders demonstrated gait biomechanics associated with osteoarthritis progression prior to the corticosteroid injection, suggesting that non-responders demonstrate more deleterious gait biomechanics prior to corticosteroid injection. Key Points • Individuals with knee osteoarthritis who were treated with extended-release corticosteroid injections demonstrated improvements in gait biomechanics and physical function for 8 weeks. • Individuals with knee osteoarthritis, who walked with aberrant walking biomechanics before treatment, failed to respond to extended-release corticosteroid treatment. • Future research should determine the mechanisms contributing to the short-term changes in gait biomechanics and physical function such as reduced inflammation.

The investigation of an analysis method for co-activation of knee osteoarthritis utilizing normalization of peak dynamic method

BACKGROUND

Assessing co-activation characteristics in knee osteoarthritis (knee OA) using method of quantification of the activity ratio (such as the co-contraction index (CCI) or the directed co-activation ratios (DCAR)) for surface electromyography (EMG) has been reported. However, no studies have discussed the differences in results between non-negative matrix factorization (NNMF) and the DCAR.

RESEARCH QUESTION

Does DCAR or NNMF reflect the characteristic co-activation pattern of knee OA while using EMG normalized by the peak dynamic method?

METHODS

Ten elderly control participants (EC) and ten knee OA patients (KOA) volunteered to participate in this study. EMG data from 20 participants were obtained from our previous study. Patients with knee OA were recruited from a local orthopedic clinic. The DCAR of agonist and antagonist muscles and the number of modules using NNMF were calculated to evaluate multiple muscle co-activations. An independent t-test statistical parametric mapping approach was used to compare the DCAR between the two groups. The difference in the number of modules between EC and KOA was evaluated using the Wilcoxon rank-sum test.

RESULTS

There was no significant difference in the DCAR between the two groups. However, NNMF had significantly fewer modules with KOA than with EC.

SIGNIFICANCE

The NNMF with the ratio of the amplitude of each muscle and duration of activity as variables reflected the co-activation of KOA, characterized by the high synchronous and prolonged activity of each muscle. Therefore, the NNMF is suitable for extracting characteristic muscle activity patterns of knee OA independent of the normalization method.

Gait biomechanics phenotypes among total knee arthroplasty candidates by machine learning cluster analysis

Knee osteoarthritis patient phenotyping is relevant to developing targeted treatments and assessing the treatment efficacy of total knee arthroplasty (TKA). This study aimed to identify clusters among TKA candidates based on demographic and knee mechanic features during gait, and compare gait changes between clusters postoperatively. TKA patients underwent 3D gait analysis 1-week pre (n = 134) and 1-year post-TKA (n = 105). Principal component analysis was applied to frontal and sagittal knee angle and moment waveforms, extracting major patterns of variability. Age, sex, body mass index, gait speed, and frontal and sagittal pre-TKA angle and moment PC scores previously identified as relevant to TKA outcomes were standardized (mean = 0, SD = 1, [134 × 15]). Multidimensional scaling and machine learning-based hierarchical clustering were applied. Final clusters were validated by examining intercluster differences pre-TKA and gait feature changes (Post_PCscore  - Pre_PCscore ) by k-way Χ² and ANOVA tests. Four TKA candidate phenotypes yielded optimum clustering metrics, interpreted as higher and lower functioning clusters that were predominantly male and female. Higher functioning clusters pre-TKA (clusters 1 and 4) had more dynamic sagittal flexion moment (p < 0.001) and frontal plane adduction moment (p < 0.001) loading/un-loading patterns during stance. Post-TKA, higher functioning clusters demonstrated less knee mechanic improvements during gait (flexion angle p < 0.001; flexion moment p < 0.001). TKA candidates can be characterized by four clusters, predominately separated by sex and knee joint biomechanics. Post-TKA knee kinematics and kinetics improvements were cluster-specific; lower functioning clusters experienced more improvement. Cluster-based patient profiling may aid in triaging and developing OA management and surgical strategies meeting group-level function needs.

Patellofemoral contact forces and knee gait mechanics 3 months after ACL reconstruction are associated with cartilage degradation 24 months after surgery

OBJECTIVE

Evaluate patellofemoral cartilage health, as assessed by quantitative magnetic resonance imaging (qMRI) T2 relaxation times, 24-months after ACL reconstruction (ACLR) and determine if they were associated with patellofemoral contact forces and knee mechanics during gait 3 months after surgery.

DESIGN

Thirty individuals completed motion analysis during overground walking at a self-selected speed 3 months after ACLR. An EMG-driven neuromusculoskeletal model was used to determine muscle forces, which were then used in a previously described model to estimate patellofemoral contact forces. Biomechanical variables of interest included peak patellofemoral contact force, peak knee flexion angle and moment, and walking speed. These same participants underwent a sagittal bilateral T2 mapping qMRI scan 24-months after surgery. T2 relaxation times were estimated for both patellar and trochlear cartilage. Paired t-tests were used to compare T2 relaxation times between limbs while Pearson correlations and linear regressions were utilized to assess the association between the biomechanical variables of interest and T2 relaxation times.

RESULTS

Prolonged involved limb trochlear T2 relaxation times (vs uninvolved) were present 24-months after surgery, indicating worse cartilage health. No differences were detected in patellar cartilage. Significant negative associations were present within the involved limb for all the biomechanical variables of interest 3 months after ACLR and trochlear T2 relaxation times at 24-months. No associations were found in patellar cartilage or within the uninvolved limb.

CONCLUSIONS

Altered involved limb trochlear cartilage health is present 24-months after ACLR and may be related to patellofemoral loading and other walking gait mechanics 3 months after surgery.

Walking with shorter stride length could improve knee kinetics of patients with medial knee osteoarthritis

Walking with a shorter stride length (SL) was recently proposed for gait retraining in medial knee osteoarthritis; however it was never assessed in this patient population. This study tested the hypothesis that shortening SL while maintaining walking speed reduces knee adduction (KAM) and flexion (KFM) moments in patients with medial knee osteoarthritis. Walking trials with normal SL and SL reduced by 0.10 m and 0.15 m were recorded for 15 patients (10 men, 55.5 ± 8.7 years old, 24.6 ± 3.0 kg/m²). SL was modified using an augmented reality system displaying target footprints on the floor. Repeated one-way ANOVAs and post-hoc paired t-tests were performed to compare gait measures between normal and reduced SL. The individual effects of SL reduction were analyzed using descriptive statistics. Group analysis indicated significant decreases in KAM impulse with both SL reductions (p < 0.05). No systematic change was observed in the first peaks KAM and KFM when walking with reduced SL (p > 0.05). Individually, 33 % of the patients decreased the peak KAM, whereas 20 % decreased the KAM impulse. Among these patients with a decrease in peak KAM or in KAM impulse, 0 % and 33 % had a simultaneous increase in peak KFM, respectively. In conclusion, this study showed that SL shortening can decrease kinetic measures associated with the progression of medial knee osteoarthritis in some patients, demonstrating the importance of considering SL modifications on an individual basis. While further research is necessary, notably regarding dose-response relationships and long-term effects, these findings are particularly encouraging because SL reductions could be easily integrated into rehabilitation protocols.

Push-Off Dynamics Reveal Task-Independent Alterations in Athletes Returning to Sport after ACL Reconstruction

PURPOSE

Athletes with an anterior cruciate ligament (ACL) reconstruction (ACLR) show persisting biomechanical and neuromuscular landing alterations. So far, most research focused on the landing phase of dynamic tasks where most ACL injuries occur. This study will assess whether these landing alterations are also present in the propulsion phase, in an attempt to identify generalized movement alterations.

METHODS

Twenty-one athletes with ACLR (cleared by their surgeon and/or physiotherapist for return-to-sport) and twenty-one controls performed five single-leg hop tasks. Propulsion kinematics, kinetics, and muscle activations were compared between legs and between groups.

RESULTS

Increased hamstrings activation was found during propulsion when comparing the ACLR limb with both the uninjured limb and the controls. In addition, decreased internal knee extension moments were found in the ACLR limb compared with the uninjured limb.

CONCLUSIONS

Athletes with ACLR show task-independent alterations that unload the knee during the propulsion phase of single-leg hopping tasks. If longitudinal data deem these alterations to be maladaptive, more emphasis must be placed on their normalization during the propulsion phase, assuming beneficial carryover effects into the landing phase. Normalizing these patterns during rehabilitation may potentially reduce the risk of long-term complications such as reinjuries and posttraumatic osteoarthritis.

Effect of a programme of muscular endurance, balance and gait exercises with and without the use of flexible and minimalist shoes in older women with medial knee osteoarthritis: study protocol for a randomised controlled trial

INTRODUCTION

Studies have indicated that gait intervention programmes with minimalist shoes are effective for reducing pain, improving functionality and reducing knee joint overload in older women with knee osteoarthritis (OA). Other clinical trials with knee and foot muscle strength training and/or dynamic balance training have also shown clinical and functional effectiveness. Despite promising strategies, there is no evidence of the combination of shoes with gait intervention programmes. Thus, the objective of this randomised clinical trial is to investigate the effects of therapeutic programme of muscular resistance, balance and gait exercises with and without the use of low-cost, flexible shoes on the clinical, functional and biomechanical aspects of older women with medial knee OA.

METHODS AND ANALYSIS

This randomised controlled trial with blinded evaluators will involve 36 older women. Twenty-four older women with knee OA (medial compartment) will be randomised to the intervention groups with minimalist shoes (GIC; n=12) or in a barefoot condition (GID; n=12), and 12 older women to the control group (n=12). The intervention protocol will consist of knee-foot muscle resistance and static balance training, reactive and proactive dynamic balance training, and gait training with visual feedback. The intervention will have a duration of two consecutive months, twice a week, totalling 16 sessions. The primary outcomes will be walking pain measured by Visual Analogue Scale and questionnaires: Western Ontario McMaster Universities Osteoarthritis Index and Lequesne Algofunctional. The secondary outcomes will be: 6-min walk test, Falls Risk Awareness Questionnaire, Timed Up and Go Test, and distribution of plantar load during gait and balance by pressure platform. Data will be analysed according to an intention-to-treat approach.

ETHICS AND DISSEMINATION

This study involves human participants and was approved by the ethics committee of the Universidade Santo Amaro, School Medicine, São Paulo/SP, Brazil (N°4.091.006). Participants gave informed consent to participate in the study before taking part. Investigators will communicate trial results to participants and healthcare professionals through scientific databases, social media, publications and conferences.

TRIAL REGISTRATION NUMBER

RBR-10j4bw25 in Brazilian Clinical Trial Registry.

Dose-response relationship of in vivo ambulatory load and mechanosensitive cartilage biomarkers—The role of age, tissue health and inflammation: A study protocol

Objective

To describe a study protocol for investigating the in vivo dose-response relationship between ambulatory load magnitude and mechanosensitive blood markers of articular cartilage, the influence of age, cartilage tissue health and presence of inflammation on this relationship, and its ability to predict changes in articular cartilage quality and morphology within 2 years.

Design

Prospective experimental multimodal (clinical, biomechanical, biological) data collection under walking stress and three different load conditions varied in a randomized crossover design.

Experimental protocol

At baseline, equal numbers of healthy and anterior cruciate ligament injured participants aged 20–30 or 40–60 years will be assessed clinically and complete questionnaires regarding their knee health. Biomechanical parameters (joint kinetics, joint kinematics, and surface electromyography) will be recorded while performing different tasks including overground and treadmill walking, single leg balance and hopping tasks. Magnetic resonance images (MRI) of both of knees will be obtained. On separate stress test days, participants will perform a 30-minute walking stress with either reduced (80% body weight (BW)), normal (100%BW) or increased (120%BW) load. Serum blood samples will be taken immediately before, immediately after, 30, 120 and 210 minutes after the walking stress. Concentration of articular cartilage blood biomarkers will be assessed using enzyme linked immunosorbent assays. At 24-month follow-up, participants will be again assessed clinically, undergo an MRI, complete questionnaires, and have a blood sample taken.

Conclusion

The study design provides a standardized set up that allows to better understand the influence of ambulatory load on articular cartilage biomarkers and thereby extend current knowledge on in vivo cartilage metabolism and mechanosensitivity. Further, this study will help to elucidate the prognostic value of the load-induced cartilage biomarker response for early articular cartilage degeneration.

Trial registration

The protocol was approved by the regional ethics committee and has been registered at clinicaltrials.gov (NCT04128566).

Reconnoitering the Therapeutic Role of Curcumin in Disease Prevention and Treatment: Lessons Learnt and Future Directions

Turmeric is a plant with a very long history of medicinal use across different cultures. Curcumin is the active part of turmeric, which has exhibited various beneficial physiological and pharmacological effects. This review aims to critically appraise the corpus of literature associated with the above pharmacological properties of curcumin, with a specific focus on antioxidant, anti-inflammatory, anticancer and antimicrobial properties. We have also reviewed the different extraction strategies currently in practice, highlighting the strengths and drawbacks of each technique. Further, our review also summarizes the clinical trials that have been conducted with curcumin, which will allow the reader to get a quick insight into the disease/patient population of interest with the outcome that was investigated. Lastly, we have also highlighted the research areas that need to be further scrutinized to better grasp curcumin’s beneficial physiological and medicinal properties, which can then be translated to facilitate the design of better bioactive therapeutic leads.

Experimental-analytical approach to assessing mechanosensitive cartilage blood marker kinetics in healthy adults: dose-response relationship and interrelationship of nine candidate markers

Purpose: To determine the suitability of selected blood biomarkers of articular cartilage as mechanosensitive markers and to investigate the dose-response relationship between ambulatory load magnitude and marker kinetics in response to load. 

Methods: Serum samples were collected from 24 healthy volunteers before and at three time points after a 30-minute walking stress test performed on three test days. In each experimental session, one of three ambulatory loads was applied: 100% body weight (BW); 80%BW; 120%BW. Serum concentrations of COMP, MMP-3, MMP-9, ADAMTS-4, PRG-4, CPII, C2C and IL-6 were assessed using commercial enzyme-linked immunosorbent assays. A two-stage analytical approach was used to determine the suitability of a biomarker by testing the response to the stress test (criterion I) and the dose-response relationship between ambulatory load magnitude and biomarker kinetics (criterion II). 

Results. COMP, MMP-3 and IL-6 at all three time points after, MMP-9 at 30 and 60 minutes after, and ADAMTS-4 and CPII at immediately after the stress test showed an average response to load or an inter-individual variation in response to load of up to 25% of pre-test levels. The relation to load magnitude on average or an inter-individual variation in this relationship was up to 8% from load level to load level. There was a positive correlation for the slopes of the change-load relationship between COMP and MMP-3, and a negative correlation for the slopes between COMP, MMP-3 and IL-6 with MMP-9, and COMP with IL6. 

Conclusions: COMP, MMP-3, IL-6, MMP-9, and ADAMTS-4 warrant further investigation in the context of articular cartilage mechanosensitivity and its role in joint degeneration and OA. While COMP seems to be able to reflect a rapid response, MMP-3 seems to reflect a slightly longer lasting, but probably also more distinct response. MMP-3 showed also the strongest association with the magnitude of load.

Knee varus alters three-dimensional ankle alignment in standing- a study with upright computed tomography

Background

For knee osteoarthritis (OA) treatment, it is important to correct the lower limb alignment including the foot. However, in the upright position, lower limb alignment is generally assessed from the body surface or radiographs, and it is a challenge to capture the exact characteristics of three-dimensional lower limb alignment. The purpose of the study was to measure lower limb alignment in patients with knee OA using upright computed tomography (CT) and radiography, and to identify features of knee joint deformity.

Methods

A total of 45 limbs in 25 patients with knee OA were enrolled. The subjects underwent both upright CT and radiography for the whole lower limb in the standing position. The joint angles were calculated on both images. The degree of knee OA was classified according to Kellgren-Lawrence (KL) grade by referring to radiography, which is mainly based on the degree of articular cartilage loss and severity of osteophytes, and the characteristics or correlation between knee and ankle joint in each group was investigated.

Results

In KL-I, there was an association between varus of the knee joint and internal rotation of the talocrural joint (r = 0.76, P < 0.05). In KL-II, there was an association between varus of the knee joint and eversion of the subtalar joint (r = 0.63, P < 0.05) and talocrural joint (r = − 0.65, P < 0.05). In KL-III, there was an association between varus of the knee joint and internal rotation of the subtalar joint (r = − 0.62, P < 0.05), and in KL-IV, there was an association between varus of the knee joint and internal rotation of the subtalar joint (r = − 0.58, P < 0.05).

Conclusions

The lower limb alignment of patients with knee OA in the standing position was found that as knee OA worsened, it became apparent that compensatory knee joint alignment depended on the ankle joint rather than the subtalar joint. The results may help in the rehabilitation of patients with knee OA, since the ankle joint alignment has a significant impact on the knee joint during coarse movements involving load.

Cartilage oligomeric matrix protein responses to a mechanical stimulus associate with ambulatory loading in individuals with anterior cruciate ligament reconstruction

Mechanical factors have been implicated in the development of osteoarthritis after anterior cruciate ligament (ACL) reconstruction. This study tested for associations between ambulatory joint loading (total joint moment [TJM] and vertical ground reaction force [vGRF]) and changes in serum levels of cartilage oligomeric matrix protein (COMP) in response to a mechanical stimulus (30-min walk) in individuals with ACL reconstruction. Twenty-five subjects (mean age: 34.5 ± 9.8 years; 2.2 ± 0.2 years post-surgery) with primary unilateral ACL reconstruction underwent gait analysis for assessment of peak vGRF and TJM first (TJM1) and second (TJM2) peaks. Serum COMP concentrations were measured by enzyme-linked immunosorbent assay immediately before, 3.5 h, and 5.5 h after a 30-min walk. Pearson correlation coefficients and backward stepwise multiple linear regression analysis, with adjustments for age, sex, body mass index, and between-limb speed difference, assessed associations between changes in COMP and between-limb differences in joint loading parameters. Greater TJM1 (R = 0.542, p = 0.005), TJM2 (R = 0.460, p = 0.021), and vGRF (R = 0.577, p = 0.003) in the ACL-reconstructed limb as compared to the contralateral limb were associated with higher COMP values 3.5 h following the 30-min walk. Change in COMP at 5.5 h became a significant predictor of the between-limb difference in TJM1 and vGRF in multivariate analyses after accounting for the between-limb speed difference. These results demonstrate that higher TJM and vGRF in the ACLR limb as compared to the contralateral limb are associated with higher relative COMP levels 3.5 and 5.5 h after a 30-min walk. Future work should investigate the effect of therapies to alter joint loading on the biological response in individuals after ACL reconstruction.

An Expert-Supervised Registration Method for Multiparameter Description of the Knee Joint Using Serial Imaging

As knee osteoarthritis is a disease of the entire joint, our pathophysiological understanding could be improved by the characterization of the relationships among the knee components. Diverse quantitative parameters can be characterized using magnetic resonance imaging (MRI) and computed tomography (CT). However, a lack of methods for the coordinated measurement of multiple parameters hinders global analyses. This study aimed to design an expert-supervised registration method to facilitate multiparameter description using complementary image sets obtained by serial imaging. The method is based on three-dimensional tissue models positioned in the image sets of interest using manually placed attraction points. Two datasets, with 10 knees CT-scanned twice and 10 knees imaged by CT and MRI were used to assess the method when registering the distal femur and proximal tibia. The median interoperator registration errors, quantified using the mean absolute distance and Dice index, were ≤0.45 mm and ≥0.96 unit, respectively. These values differed by less than 0.1 mm and 0.005 units compared to the errors obtained with gold standard methods. In conclusion, an expert-supervised registration method was introduced. Its capacity to register the distal femur and proximal tibia supports further developments for multiparameter description of healthy and osteoarthritic knee joints, among other applications.

Post-traumatic Osteoarthritis in Rabbits Following Traumatic Injury and Surgical Reconstruction of the Knee

Post-traumatic osteoarthritis (PTOA) of the knee is often attributed to anterior cruciate ligament (ACL) and meniscus injury. The development of PTOA, however, does not seem to depend on whether or not the damaged ACL is reconstructed. There has been a need to develop animal models to study the mechanisms of PTOA following reconstruction of a traumatized knee. Eighteen rabbits underwent closed-joint trauma to produce ACL rupture and meniscus damage. Then, for the first time, the traumatized knee was surgically repaired in this animal model. Upon euthanasia at 1-, 3- or 6-month post-trauma, joint stability, cartilage morphology and mechanical properties, as well as histology of the cartilage and subchondral bone were evaluated. Trauma-induced knee injury involved 72% mid-substance ACL rupture, 28% partial ACL tear and 56% concurrent medial meniscal damage. ACL reconstruction effectively restored joint stability by reducing joint laxity to a level similar to that in the contralateral intact knee. Compared to their contralateral controls, reconstructed limbs showed osteoarthritic changes to the cartilage and subchondral bone as early as 1-month post-trauma. The degeneration progressed over time up to 6-month. Overall, the medial compartments had more tissue damage than their corresponding lateral counterparts. Damage patterns to the ACL, the frequency of observed concurrent meniscal injury, and reductions in cartilage integrity and health were consistent with clinical observations of human patients who undergo ACL injury and reconstruction. Thus, we believe the combined closed-joint injury and surgical repair lapine model of PTOA, being first-ever and clinically relevant, shows promise to evaluate well-targeted therapeutics and other interventions for this chronic disease.

Knee cartilage T2 relaxation times 3 months after ACL reconstruction are associated with knee gait variables linked to knee osteoarthritis

Osteoarthritis development after ACL reconstruction (ACLR) is not well understood. Investigators have examined associations between knee biomechanical alterations and quantitative MRI (qMRI) variables, reflective of cartilage health, 12-60 months following ACLR; however, none have done so early after surgery. As part of an exploratory study, 45 individuals (age, 23 ± 7 years) underwent motion analysis during walking and qMRI 3 months after ACLR. For each limb, peak knee adduction moment (pKAM) and peak knee flexion moment (pKFM) were determined using inverse dynamics and peak medial compartment force was calculated using a neuromusculoskeletal model. T₂ relaxation times in the medial compartment and linear regressions were used to determine the associations between gait variables and deep and superficial cartilage T₂ relaxation times in six regions. pKAM was positively associated with deep layer T₂ relaxation times within the femoral central and posterior regions when examined in the involved limb and from an interlimb difference perspective (involved limb - uninvolved limb). After adjusting for age, the association between interlimb difference of pKAM and interlimb difference of deep layer T₂ relaxation times in the tibial central region became significant (p = .043). Interlimb difference of pKFM was negatively associated with interlimb difference of deep layer T₂ relaxation times within the femoral central and posterior regions. These associations suggest that degenerative pathways leading to osteoarthritis may be detectable as early as 3 months after reconstruction. Preventative therapeutic techniques may need to be employed early in the rehabilitation process to prevent cartilage degradation.

Vertical Drop Jump Biomechanics of Patients With a 3- to 10-Year History of Youth Sport-Related Anterior Cruciate Ligament Reconstruction

Background

A better understanding of movement biomechanics after anterior cruciate ligament reconstruction (ACLR) could inform injury prevention, knee injury rehabilitation, and osteoarthritis prevention strategies.

Purpose

To investigate differences in vertical drop jump (VDJ) biomechanics between patients with a 3- to 10-year history of youth sport-related ACLR and uninjured peers of a similar age, sex, and sport.

Study Design

Cross-sectional study. Level of evidence III.

Methods

Lower limb kinematics and bilateral ground-reaction forces (GRFs) were recorded for participants performing 10 VDJs. Joint angles and GRF data were analyzed, and statistical analysis was performed using 2 multivariate models. Dependent variables included sagittal (ankle, knee, and hip) and coronal (knee and hip) angles at initial contact and maximum knee flexion, the rate of change of coronal knee angles (35%-90% of the support phase; ie, slopes of linear regression lines), and vertical and mediolateral GRFs (normalized to body weight [BW]). Fixed effects included group, sex, and time since injury. Participant clusters, defined by sex and sport, were considered as random effects.

Results

Participants included 48 patients with a history of ACLR and 48 uninjured age-, sex-, and sport-matched controls (median age, 22 years [range, 18-26 years]; 67% female). Patients with ACLR demonstrated steeper negative coronal knee angle slopes (β = -0.04 deg/% [95% CI, -0.07 to -0.00 deg/%]; P = .025). A longer time since injury was associated with reduced knee flexion (β = -0.2° [95% CI, -0.3° to -0.0°]; P = .014) and hip flexion (β = -0.1° [95% CI, -0.2° to -0.0°]; P = .018). Regardless of ACLR history, women displayed greater knee valgus at initial contact (β = 2.1° [95% CI, 0.4° to 3.8°]; P = .017), greater coronal knee angle slopes (β = 0.05 deg/% [95% CI, 0.02 to 0.09 deg/%]; P = .004), and larger vertical GRFs (landing: β = -0.34 BW [95% CI, -0.61 to -0.07 BW]; P = .014) (pushoff: β = -0.20 BW [95% CI, -0.32 to -0.08 BW]; P = .001).

Conclusion

Women and patients with a 3- to 10-year history of ACLR demonstrated VDJ biomechanics that may be associated with knee motion control challenges.

Clinical Relevance

It is important to consider knee motion control during activities such as VDJs when developing injury prevention and rehabilitation interventions aimed at improving joint health after youth sport-related ACLR.

Cartilage Matrix Degeneration Occurs within the First Year after ACLR and Is Associated with Impaired Clinical Outcome

OBJECTIVE

Anterior cruciate ligament reconstruction (ACLR) has not been shown to decrease the risk for development of post-traumatic osteoarthritis. Magnetic resonance imaging (MRI) T2 mapping can be used to assess cartilage compositional changes. This study tests whether (1) worse cartilage arthroscopic status at ACLR is reflected by higher cartilage T2 values in matched study regions 6 weeks and 1 year after ACLR, and (2) increasing cartilage T2 values between 6 weeks and 1 year after ACLR are associated with worsening patient-reported outcomes.

DESIGN

Twenty-two participants with ACLR and 26 controls underwent 3T MRI. T2 values in medial and lateral femoral and tibial cartilage were measured at 6 weeks and 1 year after ACLR and compared with arthroscopic grades, Knee injury and Osteoarthritis Outcome Scores (KOOS), and control T2 values.

RESULTS

Most (59%-86%) cartilage study regions examined by arthroscopy demonstrated intact articular surfaces. Average T2 value increased in 3 of 4 study regions between 6 weeks and 1 year after ACLR (P = .001-.011). T2 value increased (P < .013) even for participants whose cartilage had intact articular surfaces at ACLR. Participants with ACLR who showed greater increases in cartilage T2 values had less improvement to KOOS Quality of Life (P = .009, ρ = -0.62).

DISCUSSION

Cartilage status assessed arthroscopically at ACLR and by MRI T2 maps 6 weeks later was healthier than cartilage status assessed by MRI T2 maps at 1-year follow-up. Progressive T2 elevations were observed over the first year after ACLR even in patients with arthroscopically intact cartilage at the time of surgery and were associated with reduced improvement in knee quality of life suggesting preosteoarthritis.

Sex-Specific Associations between Cartilage Structure and Metabolism at Rest and Acutely Following Walking and Drop-Landing

OBJECTIVE

Cartilage health is thought to be dependent on the relationship between mechanics, structure, and metabolism, rather than these individual components in isolation. Due to sex differences in cartilage health, there is need to determine if the relationships between these cartilage components separately for males and females. Therefore, we sought to determine the sex-specific associations between cartilage structure and metabolism at rest and their acute response following walking and drop-landing in healthy individuals.

DESIGN

A cartilage ultrasound assessment and an ante-cubital blood draw were performed before and after walking and drop-landing conditions in 20 males and 20 females. Cartilage structure was assessed via medial and lateral femoral cartilage cross-sectional area. Cartilage metabolism was quantified with serum cartilage oligomeric matrix protein (COMP) concentration. Percent change scores from pre- to postloading were used to calculate acute alterations in cross-sectional area and COMP. Correlational analyses were used to assess the association between cartilage structure and metabolism measures separately for males and females.

RESULTS

In females, greater resting COMP concentration was associated with less cartilage cross-sectional area in the medial(ρ = -0.50, P = 0.03) and lateral (ρ = -0.69, P = 0.001) femur. Resting cartilage measures were not associated among males. Following walking and drop-landing, percent change scores in cartilage structure and metabolism were not associated.

CONCLUSIONS

This study highlights that, in females, thinner anterior femoral cartilage is associated with greater resting serum COMP concentrations, a biomarker often linked to cartilage breakdown. Future studies into the relationships between various cartilage components should consider sex-specific analyses as these relationships are sex dependent.

Integrative Analysis of the Expression of microRNA, Long Noncoding RNA, and mRNA in Osteoarthritis and Construction of a Competing Endogenous Network

This study aimed to identify potential core microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and mRNAs in osteoarthritis (OA) to construct a competing endogenous RNA (ceRNA) and co-expression network. Differentially expressed miRNAs (DEMis) in the dataset GSE143514 comprising five OA and three normal tissues were identified using the DEseq package. Core miRNAs were identified as DEMis overlapping with those reported by the human microRNA disease database. LncRNAs were predicted by the miRNA-lncRNA interactions network from the encyclopedia of RNA interactomes (ENCORI). MiRNet and ENCORI were employed to predict the mRNAs which overlapped with the differentially expressed mRNAs from the dataset GSE114007 to obtain overlapping mRNAs. MiRNA-lncRNA and miRNA-mRNA interactions were integrated to construct the ceRNA network. A total of 143 DEMis were identified in OA and normal tissues, from which hsa-miR-451a, hsa-miR-370-5p, hsa-miR-34a-5p, hsa-miR-210-3p, and hsa-miR-101-3p were assessed as core miRNAs using overlapping analyses. These RNAs may represent potential therapeutic targets for the treatment of OA.

Stepping Back to Minimal Footwear: Applications Across the Lifespan

Minimal footwear has existed for tens of thousands of years and was originally designed to protect the sole of the foot. Over the past 50 yr, most footwear has become increasingly more cushioned and supportive. Here, we review evidence that minimal shoes are a better match to our feet, which may result in a lower risk of musculoskeletal injury.

Association between changes in the knee adduction moment and changes in knee pain and function in response to non-surgical biomechanical interventions for medial knee osteoarthritis: a systematic review

There is lack of understanding of the relationship between knee adduction moment (KAM) reductions and improvements in pain or function in patients with knee osteoarthritis (KOA). Moreover, there is no systematic review describing the longitudinal relationship between KAM changes and subsequent changes in pain and/or physical function. We aimed (1) to investigate the relationship between changes in KAM induced by non-surgical biomechanical interventions and consecutive changes in pain and/or physical function in patients with medial KOA and (2) to compare this relationship for different interventions. We considered eligible all RCTs using biomechanical interventions aimed to reduce KAM in KOA patients, that measured pain/function. We used Cohen's d effect size to quantify outcome measurements. 14 papers reporting 11 studies were identified. Braces were tested in 6 studies, insoles in 5 studies, shoes in 3 studies and gait retraining in 2 studies. Methodological differences were large among studies. Large effect sizes (≥0.8) changes in pain/function were observed with interventions having at least a small KAM effect size (≥0.2), suggesting an association between KAM and pain/function changes. A linear trend was observed between inter-intervention KAM and VAS pain effect sizes, based on 4 studies. No firm conclusions could be drawn for the different intervention types. There was a trend toward larger KAM reductions leading to larger improvements in pain/function in non-surgical biomechanical interventions. Additional high-quality RCT with consistent methodology are needed to fully characterize the association between KAM and pain/function changes.

Visualizing pre-osteoarthritis: Integrating MRI UTE-T2* with mechanics and biology to combat osteoarthritis-The 2019 Elizabeth Winston Lanier Kappa Delta Award

Osteoarthritis (OA) is a leading cause of pain and disability for which disease-modifying treatments remain lacking. This is because the symptoms and radiographic changes of OA occur after the onset of likely irreversible changes. Defining and treating earlier disease states are therefore needed to delay or to halt OA progression. Taking this concept a step further, studying OA pathogenesis before disease onset by characterizing potentially reversible markers of increased OA risk to identify a state of "pre-osteoarthritis (pre-OA)" shifts the paradigm towards OA prevention. The purpose of this review is to summarize the 42 studies comprising the 2019 Kappa Delta Elizabeth Lanier Award where conceptualization of a systems-based definition for "pre-osteoarthritis (pre-OA)" was followed by demonstration of potentially reversible markers of heightened OA risk in patients after anterior cruciate ligament (ACL) injury and reconstruction. In the process, these efforts contributed a new magnetic resonance imaging method of ultrashort echo time (UTE) enhanced T2* mapping to visualize joint tissue damage before the development of irreversible changes. The studies presented here support a transformative approach to OA that accounts for interactions between mechanical, biological, and structural markers of OA risk to develop and evaluate new treatment strategies that can delay or prevent the onset of clinical disease. This body of work was inspired by and performed for patients. Shifting the paradigm from attempting to modify symptomatic radiographic OA towards monitoring and reversing markers of "pre-OA" opens the door for transforming the clinical approach to OA from palliation to prevention.

Changes in anterior femoral articular cartilage structure in collegiate rugby athletes with and without a history of traumatic knee joint injury following a five-month competitive season

This study aimed to examine anterior femoral cartilage morphology before (pre-season) and after (post-season) a 5-month competitive season in collegiate ruby players with and without a previous history of traumatic injury to ligamentous, meniscus, and/or cartilage structures at the knee joint. Using a prospective cohort design, 42 male collegiate rugby players with a previous history of traumatic intracapsular knee joint injury and 124 players without knee injury history were included in this study. Ultrasonography assessments of anterior femoral cartilage were performed before (pre-season) and following a 5-month athletic season (post-season). Rugby players with a history of traumatic knee joint injury had greater lateral condylar thickness (2.37 ± 0.35 mm, p = 0.03), intercondylar thickness (2.51 ± 0.47 mm, p = 0.03), and partial area (44.67 ± 7.28mm², p = 0.02) compared to control players (lateral = 2.23 ± 0.35 mm, intercondylar = 2.32 ± 0.47 mm, partial area = 41.60 ± 7.26 mm²), regardless of pre-and post-season assessment time points. Pre-season ultrasonography assessment of lateral condylar thickness (2.34 ± 0.47 mm, p = 0.02), medial condylar thickness (2.05 ± 0.43 mm, p = 0.03), and partial area (44.10 ± 9.23 mm², p = 0.001) were significantly greater than the post-season ultrasonography assessment time point (lateral = 2.26 ± 0.43 mm, medial = 1.98 ± 0.43 mm, partial area = 42.17 ± 8.82 mm²), regardless of group membership. Rugby players with a history of intracapsular knee joint injury displayed altered anterior femoral cartilage size via ultrasonography assessments. Regardless of a presence of injury history, collegiate rugby players showed a decrease in cartilage thickness and partial area following a 5-month competitive season.

Synovial fluid concentrations of matrix Metalloproteinase-3 and Interluekin-6 following anterior cruciate ligament injury associate with gait biomechanics 6 months following reconstruction

OBJECTIVE

To compare gait biomechanics 6 months following anterior cruciate ligament (ACL) reconstruction (ACLR) between patients with the highest and lowest concentrations of synovial fluid (SF) interleukin-6 (IL-6) and matrix metalloproteinase-3 (MMP-3), as well as compared to uninjured controls.

DESIGN

SF concentrations of IL-6 and MMP-3 were collected 7 ± 4 days post injury in 38 ACL injured patients (55% female, 21±4yrs, 25.3 ± 5.2BMI). ACL injured individuals were stratified into the lowest and highest quartiles based on IL-6 (IL-6_Lowest and IL-6_Highest) and MMP-3 (MMP-3_Lowest and MMP-3_Highest) concentrations. Gait biomechanics were collected on the injured limb 6 months post-ACLR and in 38 uninjured controls (50% female, 21±3yrs, 23.8 ± 2.8BMI). Functional analyses of variance were used to compare vertical ground reaction force (vGRF), knee flexion angle (KFA), and internal knee extension moment (KEM) waveforms throughout stance phase of gait to determine the proportions of stance differing between limbs and groups.

RESULTS

Compared to uninjured controls, IL-6_High and MMP-3_High ACL subgroups demonstrated lesser vGRF (largest differences: IL-6, 7.88%BW; MMP-3, 11.05%BW) during early-stance and greater vGRF (largest differences: IL-6, 6.21%BW; MMP-3, 5.85%BW) in mid-stance, lesser KFA (largest differences: IL-6, 3.11°; MMP-3, 3.72°) and lesser KEM (largest differences: IL-6, 0.96%BW•m; MMP-3, 1.07%BW•m) in early-stance, as well as greater KFA in mid-stance (largest differences: IL-6, 1.5°; MMP-3, 2.95°).

CONCLUSIONS

High SF concentrations of a proinflammatory cytokine and a degradative enzyme early post-ACL injury are associated with aberrant gait biomechanics in the injured limb at 6 months post-ACLR (i.e., lesser vGRF, KFA and KEM) linked to posttraumatic osteoarthritis development.

Experimental-analytical approach to assessing mechanosensitive cartilage blood marker kinetics in healthy adults: dose-response relationship and interrelationship of nine candidate markers

Purpose: To determine the suitability of selected blood biomarkers of articular cartilage as mechanosensitive markers and to investigate the dose-response relationship between ambulatory load magnitude and marker kinetics in response to load.  Methods: Serum samples were collected from 24 healthy volunteers before and at three time points after a 30-minute walking stress test performed on three test days. In each experimental session, one of three ambulatory loads was applied: 100% body weight (BW); 80%BW; 120%BW. Serum concentrations of COMP, MMP-3, MMP-9, ADAMTS-4, PRG-4, CPII, C2C and IL-6 were assessed using commercial enzyme-linked immunosorbent assays. A two-stage analytical approach was used to determine the suitability of a biomarker by testing the response to the stress test (criterion I) and the dose-response relationship between ambulatory load magnitude and biomarker kinetics (criterion II).  Results. COMP, MMP-3 and IL-6 at all three time points after, MMP-9 at 30 and 60 minutes after, and ADAMTS-4 and CPII at immediately after the stress test showed an average response to load or an inter-individual variation in response to load of up to 25% of pre-test levels. The relation to load magnitude on average or an inter-individual variation in this relationship was up to 8% from load level to load level. There was a positive correlation for the slopes of the change-load relationship between COMP and MMP-3, and a negative correlation for the slopes between COMP, MMP-3 and IL-6 with MMP-9, and COMP with IL6.  Conclusions: COMP, MMP-3, IL-6, MMP-9, and ADAMTS-4 warrant further investigation in the context of articular cartilage mechanosensitivity and its role in joint degeneration and OA. While COMP seems to be able to reflect a rapid response, MMP-3 seems to reflect a slightly longer lasting, but probably also more distinct response. MMP-3 showed also the strongest association with the magnitude of load.

Longitudinal changes in tibial and femoral cartilage thickness are associated with baseline ambulatory kinetics and cartilage oligomeric matrix protein (COMP) measures in an asymptomatic aging population

OBJECTIVE

To address the need for early knee osteoarthritis (OA) markers by testing if longitudinal cartilage thickness changes are associated with specific biomechanical and biological measures acquired at a baseline test in asymptomatic aging subjects.

DESIGN

Thirty-eight asymptomatic subjects over age 45 years were studied at baseline and at an average of 7-9 year follow-up. Gait mechanics and knee MRI were measured at baseline and MRI was obtained at follow-up to assess cartilage thickness changes. A subset of the subjects (n = 12) also had serum cartilage oligomeric matrix protein measured at baseline in response to a mechanical stimulus (30-min walk) (mCOMP). Baseline measures, including the knee extension (KEM), flexion (KFM), adduction (KAM) moments and mCOMP, were tested for associations with cartilage thickness changes in specific regions of the knee.

RESULTS

Cartilage change in the full medial femoral condyle (p = 0.005) and external medial femoral region (p = 0.041) was negatively associated with larger early stance peak KEM. Similarly, cartilage change in the full medial femoral region (p = 0.009) and medial femoral external region (p = 0.043) was negatively associated with larger first peak KAM, while cartilage change in the anterior medial tibia was positively associated with larger first peak KAM (p = 0.003). Cartilage change in the anterior medial tibia was also significantly associated (p = 0.011) with mCOMP levels 5.5-h post-activity (percentage of pre-activity levels).

CONCLUSIONS

Interactions found between gait, mechanically-stimulated serum biomarkers, and cartilage thickness in an at-risk aging asymptomatic population suggest the opportunity for early detection of OA with new approaches that bridge across disciplines and scales.

Changes in knee adduction moment wearing a variable-stiffness shoe correlate with changes in pain and mechanically stimulated cartilage oligomeric matrix levels

This study aimed to determine if changes in knee adduction moment (KAM) after 6 months of variable-stiffness shoe wear are associated with changes in symptoms or serum levels of cartilage oligomeric matrix protein (COMP) following a mechanical stimulus in subjects with medial knee osteoarthritis (OA). Twenty-five subjects were enrolled in the study and assigned a variable-stiffness shoe, and 19 subjects completed the 6-month follow-up. At baseline and follow-up subjects underwent gait analysis in control and variable-stiffness shoes, completed Western Ontario and McMaster Universities (WOMAC) questionnaires, and serum COMP concentrations were measured immediately before, 3.5 and 5.5 hours after a 30-minute walking activity. Relationships between changes in KAM (first peak and impulse) and changes in (a) COMP levels in response to the 30-minute walking activity and (b) WOMAC scores from baseline to 6-month follow-up were assessed by Pearson correlation coefficients. Changes in first peak KAM were associated with changes in COMP levels 5.5 hours postactivity from baseline to follow-up (R = .564, P = .045). Subjects with greater reductions in KAM had larger decreases in COMP (expressed as a percent of preactivity levels) at follow-up. Subjects with greater reductions in KAM impulse had significantly greater improvements in WOMAC Pain (R = -.56, P = .015) and Function (R = -.52, P = .028) scores at follow-up. The study results demonstrated the magnitude of reduction in the KAM wearing a variable-stiffness shoe is associated with decreases in mechanically stimulated COMP levels and pain/function. This work suggests that interactions between COMP and joint loading during walking should be further investigated in future studies of treatment outcomes in OA.

A Randomized Controlled Trial of Eccentric Versus Concentric Cycling for Anterior Cruciate Ligament Reconstruction Rehabilitation

BACKGROUND

Persistent strength and biomechanical deviations remain after anterior cruciate ligament reconstruction (ACLR). Eccentric training may reduce these and associated reinjury or osteoarthritis risks.

HYPOTHESIS

For male patients who have undergone ACLR, eccentric training is more effective than concentric training at improving knee flexion angle and other biomechanical deviations, as well as strength and patient-reported outcomes, using a matched perceived exertion dose.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 26 men, 10-16 weeks after hamstring tendon graft ACLR, were randomized to an eccentric training group or a concentric control group. Both groups trained 3 times a week for 8 weeks using the same isokinetic cycle ergometer in a matched studio environment. Exercise dose was matched in training frequency, time, progression, and intensity using a target rating of perceived exertion. Baseline and follow-up testing included questionnaires, dynamometer strength testing, and walk/run gait analysis.

RESULTS

Eccentric training increased knee (+2.1°; P = .022) and hip (+2.1°; P = .010) flexion angles more than concentric training but not more than the minimal clinically important difference of 3°. Very large asymmetries in baseline knee abduction moment (walk, -0.10 N·m/kg/m; run, -0.54 N·m/kg/m) had not changed in either group by follow-up. Knee valgus angle effects were mixed. Tibial rotation angle increased in both groups, but concentric training was more effective at promoting symmetry (P < .001). Both groups had similar increases in affected limb quadriceps strength and knee flexion moments during walk/run gait (by 20% to 33%). Hamstring strength increased in the eccentric group (+15.4%) but not the concentric group. Eccentric group limb forces were 33% to 70% higher than those of the concentric group, with a lower heart rate. Both groups had low pain scores throughout.

CONCLUSION

For rehabilitation after ACLR, progressive eccentric cycle training was not more clinically effective than concentric training at a matched perceived intensity dose in male patients. This can guide exercise prescription for reducing gait and strength deviations of these patients.

REGISTRATION

PACTR201602001449365 (Pan African Clinical Trials Registry), NHREC 4344 (South African).

Investigating in vivo knee volumetric bone mineral density and walking gait mechanics in healthy people

The aim of this study was to investigate if the distribution of subchondral volumetric bone mineral density (vBMD) from peripheral quantitative computed tomography (pQCT) is related to estimates of knee joint loads calculated during walking gait in healthy young people. We recruited 19 young (age 18-40 years) healthy people with no self-reported knee pain or pathology. For all participants we collected two forms of data: (1) pQCT data at 2% of tibia length (from the proximal joint line) using a Stratec XCT3000 scanner at 0.2 × 0.2 mm in plane resolution; and (2) indices of joint loading, specifically external joint moment, at the indexed knee during walking gait. Joint moments were calculated from motion capture and ground reaction force data. pQCT scans were performed immediately prior to gait analysis. A sub-group of 9 participants attended a second scanning session to establish the reproducibility of the pQCT workflow. vBMD was extracted for four sub-regions (anteromedial, anterolateral, posteromedial and posterolateral). Reproducibility of the pQCT workflow was good to excellent (ICCs 0.832-0.985) with minimal detectable differences ranging from 2.3-39.5 mg HA/cm³. Significant independent correlations were identified between the external rotation moment and the medial-to-lateral (r = 0.517), posteromedial-to-posterolateral (r = 0.627) and posteromedial-to-anterolateral (r = 0.518) vBMD ratios, and between the knee adduction moment and the medial-to-lateral (r = -0.476) and posteromedial-to-posterolateral (r = -0.497) vBMD ratios. There appear to be significant relationships between measures of vBMD from pQCT and indices of joint loading in healthy people. These data are the first to combine imaging at the resolution available with pQCT and indices of joint loading in the same cohort.

Analyzing Femorotibial Cartilage Thickness Using Anatomically Standardized Maps: Reproducibility and Reference Data

Alterations in cartilage thickness (CTh) are a hallmark of knee osteoarthritis, which remain difficult to characterize at high resolution, even with modern magnetic resonance imaging (MRI), due to a paucity of standardization tools. This study aimed to assess a computational anatomy method producing standardized two-dimensional femorotibial CTh maps. The method was assessed with twenty knees, processed following three common experimental scenarios. Cartilage thickness maps were obtained for the femorotibial cartilages by reconstructing bone and cartilage mesh models in tree-dimension, calculating three-dimensional CTh maps, and anatomically standardizing the maps. The intra-operator accuracy (median (interquartile range, IQR) of -0.006 (0.045) mm), precision (0.152 (0.070) mm), entropy (7.02 (0.71) and agreement (0.975 (0.020))) results suggested that the method is adequate to capture the spatial variations in CTh and compare knees at varying osteoarthritis stages. The lower inter-operator precision (0.496 (0.132) mm) and agreement (0.808 (0.108)) indicate a possible loss of sensitivity to detect differences in a setting with multiple operators. The results confirmed the promising potential of anatomically standardized maps, with the lower inter-operator reproducibility stressing the need to coordinate operators. This study also provided essential reference data and indications for future research using CTh maps.

The contribution of age and obesity to the number of painful joint sites in individuals reporting osteoarthritis: a population-based study

Objective

To investigate the association of OA risk factors with number of painful joint sites in a representative population sample.

Methods

Analysis of the 2009 Survey on Living with Chronic Diseases in Canada – Arthritis Component (n = 1614) for respondents reporting symptomatic OA. Variables: painful joints sites (hands, wrists, elbows, shoulders, hips, knees, ankles, feet, back, neck), joint symptom duration, sociodemographic characteristics, smoking, comorbidities and BMI. Zero-truncated negative binomial regressions were used to investigate the association between number of painful joint sites and the variables. Generalizability of findings was assessed by a similar analysis in a clinical hip/knee OA sample.

Results

The sample comprised 73% women and 56% were aged <65 years. The mean number of painful joint sites was 3.8: 84% reported pain at ≥2 sites, and 45% at ≥4 sites. Age, BMI, education and smoking were not associated with the number of joint sites. Significant associations were found with being female [rate ratio (RR) = 1.23, 95% CI 1.09, 1.39], having more comorbidities (RR = 1.11, 95% CI 1.07, 1.15) and longer symptom duration (RR = 1.16, 95% CI 1.09, 1.24), although the increase in joint sites with duration was small. Similar regression results were found with the clinical OA sample.

Conclusion

The lack of an association of age and BMI (obesity) with number of painful joint sites in OA raises questions about the role of these risk factors and our understanding of OA as a multi-joint disease. Filling this knowledge gap is critical to making progress with defining OA phenotypes and identifying potential aetiological mechanisms.

Femoral Cartilage Ultrasound Echo Intensity Associates with Arthroscopic Cartilage Damage

This study compared quantitative cartilage ultrasound metrics between people with (n = 12) and without (n = 12) arthroscopic cartilage damage after anterior cruciate ligament injury (age, 24.9 ± 3.7 y; sex, 33% female, 67% male; days since injury = 50 ± 52). A transverse suprapatellar ultrasound assessment imaged the femoral cartilage in participants' injured knees before a clinical arthroscopy. A custom program automatically separated a manual cartilage segmentation into standardized medial and lateral femoral regions and calculated mean thickness (i.e., cross-sectional area/length of cartilage-bone interface), mean echo intensity and echo-intensity heterogeneity. An orthopedic surgeon assessed arthroscopic cartilage damage in the medial and lateral femoral condyles using the Outerbridge grading system (cartilage damage = Outerbridge ≥ 1). Separate logistic regressions for medial and lateral femoral cartilage were used to determine the association between each ultrasound metric and arthroscopic cartilage damage. In medial femoral cartilage, for every 1 standard deviation decrease in echo-intensity mean and heterogeneity, there is, respectively, a 91% (adjusted odds ratio, 0.09; 95% confidence interval, 0.01-0.69) and 97% (adjusted odds ratio, 0.03; 95% confidence interval, 0.002-0.50) increase in the odds of having arthroscopic cartilage damage. Lateral cartilage ultrasound metrics are not associated with lateral arthroscopic cartilage damage. This study provides preliminary evidence that femoral cartilage ultrasound echo intensity is a non-invasive measure associated with medial femoral cartilage health after anterior cruciate ligament injury.

Effect of walking on in vivo tibiofemoral cartilage strain in ACL-deficient versus intact knees

Anterior cruciate ligament (ACL) rupture alters knee kinematics and contributes to premature development of osteoarthritis. However, there is limited data regarding the in vivo biomechanical response of tibiofemoral cartilage to activities of daily living (ADLs) in ACL-deficient knees. In this study, eight otherwise healthy participants with chronic unilateral ACL deficiency completed a stress test to assess the effect of 20 min of level treadmill walking at a speed of 2.5 mph on tibiofemoral cartilage in their ACL-deficient and contralateral ACL-intact knees. Three-dimensional surface models developed from pre- and post-activity magnetic resonance (MR) images of the injured and uninjured knees were used to determine compressive strain across multiple regions of tibiofemoral cartilage (medial and lateral tibial plateaus, medial and lateral femoral condyles, medial aspect of femoral condyle adjacent to intercondylar notch of the femur). In the ACL-deficient knees, we observed significantly increased cartilage strain in the region of the medial femoral condyle adjacent to the intercondylar notch (6% in deficient vs. 2% in contralateral, p = 0.01) as well as across the medial and lateral tibial plateaus (4% vs. 3%, p = 0.01) relative to the contralateral ACL-intact knees. Increased compressive strain at the medial intercondylar notch and tibial plateau suggests alterations in mechanical loading or the response to load in these regions, presumably related to altered knee kinematics. These changes may disrupt cartilage homeostasis and contribute to subsequent development of osteoarthritis.

Effects of Catalpa Alcohol From Rehmannia glutinosa on Calcium-Binding Protein, Interleukin-1β, and Galectin-3 in Synovial Tissues of Rats With Knee Osteoarthritis

Objectives

We aimed to evaluate the effects of catalpa alcohol from Rehmannia glutinosa on the expressions of calcium-binding protein (S100A12), interleukin-1β (IL-1β), and galectin-3 in the synovium of rats with early knee osteoarthritis (KOA).

Methods

Fifty-two adult male Wistar rats aged 3 to 8 weeks were divided into normal control (n = 16), model (n = 12), low-dose (n = 12), and high-dose groups (n = 12). On the 10th day after modeling, 6 rats in normal control group and 6 in the other 3 groups were randomly selected. X-ray and 3-dimensional computed tomography (3D CT) images of the left knee joint were taken under live anesthesia. The joint cavity of sacrificed rats was opened to observe cartilage surface. After 28 consecutive days of administration, the synovial tissue of left knee joint was collected.

Results

The S100A12, IL-1β, and galectin-3 levels in synovial tissue were detected by immunohistochemistry and ELISA. There were articular cartilage defects in left knees. Radiologic examination showed significant joint space narrowing and hyperplasia, and 3D CT joint space value decreased (P &lt; 0.05). The Mankins and OARSI scores of synovial histopathology were significantly different (P &lt; 0.05). The S100A12, IL-1β, and galectin-3 levels in synovial tissue of the model group significantly exceeded those of the normal control group (P &lt; 0.01). Compared with the model group, such levels of low-dose (P &lt; 0.05) and high-dose groups (P &lt; 0.01) were significantly lower.

Conclusions

The S100A12, IL-1β and galectin-3 levels in synovium tissue decreased with rising concentration of catalpa alcohol from R. glutinosa. Therefore, this drug is potentially suitable for inhibiting an inflammatory response to delay the progression of KOA.

Effectiveness of Traditional Chinese Exercise for Symptoms of Knee Osteoarthritis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: Growing evidences have advocated the potential benefits of traditional Chinese exercise (TCE) on symptomatic improvement of knee osteoarthritis (KOA). However, most of them have been derived from cross-sectional studies or case reports; the effectiveness of TCE therapies has not been fully assessed with a randomized control trial (RCT). In order to evaluate the combined clinical effectiveness of TCE for KOA, we conducted a systematic review and meta-analysis on the existing RCTs on KOA. Methods: A systematic search was performed in four electronic databases: PubMed, Web of Science, Cochrane Library, and EMBASE from the time of their inception to February 2020. All eligible RCTs were included in which TCE was utilized for treating KOA as compared to a control group. Two reviewers independently extracted the data and evaluated the risk of bias following the Cochrane Risk of Bias Tool for RCT. The symptoms of KOA evaluated by the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and the Knee Injury and Osteoarthritis Outcome Score (KOOS) were regarded as the primary outcomes in this study. Each outcome measure was pooled by a standardized mean difference (SMD) with 95% confidence intervals (CI). A meta-analysis was applied with a random or fixed effect model for the collected data to calculate the summary SMD with 95% CI based on different statistical heterogeneity. In addition, subgroup analyses were used to investigate heterogeneity and sensitivity analysis was carried out for the results of the meta-analysis. Egger’s test and the funnel plots were used to examine the potential bias in the RCTs. Results: A total of 14 RCTs involving 815 patients with KOA were included. Compared with a control group; the synthesized data of TCE showed a significant improvement in WOMAC/KOOS pain score (SMD = −0.61; 95% CI: −0.86 to −0.37; p < 0.001), stiffness score (SMD = −0.75; 95% CI: −1.09 to −0.41; p < 0.001), and physical function score (SMD = −0.67; 95% CI: −0.82 to −0.53; p < 0.001). Conclusions: Our meta-analysis suggested that TCE may be effective in alleviating pain; relieving stiffness and improving the physical function for patients with KOA. Yet; given the methodological limitations of included RCTs in this meta-analysis; more high-quality RCTs with large sample size and long-term intervention are required to further confirm the effectiveness and underlying mechanisms of TCE for treating KOA.

Sustained acoustic medicine as a non-surgical and non-opioid knee osteoarthritis treatment option: a health economic cost-effectiveness analysis for symptom management

Background

Patients diagnosed with osteoarthritis (OA) and presenting with symptoms are seeking conservative treatment options to reduce pain, improve function, and avoid surgery. Sustained acoustic medicine (SAM), a multi-hour treatment has demonstrated improved clinical outcomes for patients with knee OA. The purpose of this analysis was to compare the costs and effectiveness of multi-hour SAM treatment versus the standard of care (SOC) over a 6-month timeframe for OA symptom management.

Methods

A decision tree analysis was used to compare the costs and effectiveness of SAM treatment versus SOC in patients with OA. Probabilities of success for OA treatment and effectiveness were derived from the literature using systematic reviews and meta-analyses. Costs were derived from Medicare payment rates and manufacturer prices. Functional effectiveness was measured as the effect size of a therapy and treatment pathways compared to a SOC treatment pathway. A sensitivity analysis was performed to determine which cost variables had the greatest effect on deciding which option was the least costly. An incremental cost-effectiveness plot comparing SAM treatment vs. SOC was also generated using 1000 iterations of the model. Lastly, the incremental cost-effectiveness ratio (ICER) was calculated as the (cost of SAM minus cost of SOC) divided by (functional effectiveness of SAM minus functional effectiveness of SOC).

Results

Base case demonstrated that over 6 months, the cost and functional effectiveness of SAM was $8641 and 0.52 versus SOC at: $6281 and 0.39, respectively. Sensitivity analysis demonstrated that in order for SAM to be the less expensive option, the cost per 15-min session of PT would need to be greater than $88, or SAM would need to be priced at less than or equal to $2276. Incremental cost-effectiveness demonstrated that most of the time (84%) SAM treatment resulted in improved functional effectiveness but at a higher cost than SOC.

Conclusion

In patients with osteoarthritis, SAM treatment demonstrated improved pain and functional gains compared to SOC but at an increased cost. Based on the SAM treatment ICER score being ≤ $50,000, it appears that SAM is a cost-effective treatment for knee OA.

Medicare coverage patterns favor non-invasive and minimally-invasive treatments of knee osteoarthritis compared to temporomandibular joint osteoarthritis

OBJECTIVE

To compare Medicare coverage patterns for treatments of knee osteoarthritis (OA) to those of temporomandibular joint (TMJ) OA.

METHODS

The International Classification of Diseases (ICD)-10 codes were used to identify knee OA, TMJ OA, and related diagnoses. The AAPC Coder was utilized to search for Medicare insurance coverage by state/district for the indicated CPT codes. The coverage for treatments of TMJ OA and knee OA was analyzed by Fisher's exact test.

RESULTS

There was a statistically significant difference in the coverage of physical therapy, massage therapy, and arthrocentesis for TMJ OA and knee OA. The current study showed that arthrocentesis was covered 100% in all states/districts for knee OA and 0% for TMJ OA.

CONCLUSION

Medicare covers TMJ OA treatments to a lesser degree than knee treatments. Documentation of this discrepancy serves as an important first step in advocating for improvements in coverage, and subsequently, in access to care.