Biomechanical effects of valgus knee bracing: a systematic review and meta-analysis

Functions and Effectiveness of Unloader, Patellofemoral, and Knee Sleeve Orthoses: A Review

Background

Knee orthoses have been extensively used as a nonsurgical approach to improving knee deficiencies. Currently, arthritic knee conditions remain the leading cause of disability, and this number is expected to increase. As the use of knee orthoses varies widely, so has their effectiveness which is still largely debatable. Here, we present the functions and effectiveness of the three most prominent knee orthotic models dedicated to supporting knee osteoarthritis-unloader, patellofemoral, and knee sleeves.

Purpose/Research Question

Considering the depth and diversity of the many clinical studies and documented laboratory reports published to date, this literature review was created to educate the clinician, patient, and researcher on common knee orthoses used for the management of arthritic knee conditions. In doing so, we discuss their design, biomechanical effects, and clinical efficacy, as well as broader outcomes, limitations, and recommendations for use.

Results/Synthesis

The knee orthoses discussed within the scope of this paper are dedicated to protecting the knee against strenuous compressive loads that may affect the patellofemoral and tibiofemoral joints of the knee. Since the knee has multiple axes of motion and articulating surfaces that experience different loads during functional activities, it can be implied that, to a large extent, knee brace designs can differ drastically. Unloader knee orthoses are designed to decrease tibiofemoral and patellofemoral joint pressures. Patellofemoral knee orthoses are designed to decrease strain on the patellofemoral and quadriceps tendons while stabilizing the patella. Knee sleeves are designed to stabilize movements, reduce pain in joints, and improve proprioception across the knee joint.

Conclusion

Although patients often report benefits from wearing braces, these benefits have not been confirmed by clinicians and scientific investigators. Results from these three orthosis types show that clinical efficacy is still elusive due to the different methodologies used by researchers.

Layman Summary

Knee orthoses also referred to as knee brace are commonly used for support and stability of the knee. Unloader knee braces are designed to relieve and support those suffering from knee osteoarthritis by improving physical impairment and reducing pain. Patellofemoral knee braces aim to help patients manage patellofemoral pain syndrome. Rehabilitative compression sleeves, also known as knee sleeves, are often used to assist patients suffering from knee pain and laxity. Important findings on the three knee braces discussed show discrepancies in results. Their effectiveness and validity are yet to be understood.

Unicompartmental knee arthroplasty vs high tibial osteotomy for knee osteoarthritis: A comparison of clinical and radiological outcomes

BACKGROUND

Unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO) are well-established operative interventions in the treatment of knee osteoarthritis. However, which intervention is more beneficial to patients with knee osteoarthritis remains unknown and a topic of much debate. Simultaneously, there is a paucity of research assessing the relationship between radiographic parameters of knee joint alignment and patient-reported clinical outcomes, preoperatively and following HTO or UKA.

AIM

To compare UKAs and HTOs as interventions for medial-compartment knee osteoarthritis: Examining differences in clinical outcome and investigating the relationship of joint alignment with respect to this.

METHODS

This longitudinal observational study assessed a total of 42 patients that had undergone UKA (n = 23) and HTO (n = 19) to treat medial compartment knee osteoarthritis. Patient-reported outcome measures (PROMs) were collected to evaluate clinical outcome. These included two disease-specific (Knee Injury and Osteoarthritis Outcome Score, Oxford Knee Score) and two generic (EQ-5D-5L, Short Form-12) PROMs. The radiographic parameters of knee alignment assessed were the: Hip-knee-ankle angle, mechanical axis deviation and angle of Mikulicz line.

RESULTS

Statistical analyses demonstrated significant (P < 0.001), preoperative to postoperative, improvements in the PROM scores of both groups. There were, however, no significant inter-group differences in the postoperative PROM scores of the UKA and HTO group. Several significant correlations associated a more distolaterally angled Mikulicz line with worse knee function and overall health preoperatively (P < 0.05). Postoperatively, two clusters of significant correlations were observed between the disease-specific PROM scores and knee joint alignment parameters (hip-knee-ankle angle, mechanical axis deviation) within the HTO group; yet no such associations were observed within the UKA group.

CONCLUSION

UKAs and HTOs are both efficacious operations that provide a comparable degree of clinical benefit to patients with medial compartment knee osteoarthritis. Clinical outcome has a limited association with radiographic parameters of knee joint alignment postoperatively; however, a more distolaterally angled Mikulicz line appears associated with worse knee function/health-related quality of life preoperatively.

Toe-in and toe-out gait retraining interventions to reduce proxy measures of medial knee joint load in people with medial knee osteoarthritis: Protocol for a randomised placebo-controlled trial

OBJECTIVE

Our primary aim is to determine the effect of a six-week toe-in, toe-out and active placebo gait retraining program on proxy measures of medial knee joint load and varus thrust in people with medial knee osteoarthritis. Our secondary aim is to determine the intervention effects on patient reported outcomes and physical function and determine if changes are maintained at three-months follow-up.

METHODS

We will conduct a three-arm randomised placebo-controlled trial. Ninety participants with medial knee osteoarthritis will be randomised and stratified via varus thrust status (presence/absence) to: toe-in, toe-out or placebo gait retraining (an intervention that does not change proxy measures of medial knee joint load). The intervention involves weekly clinician-supervised sessions with biofeedback, knee osteoarthritis education, motor learning and behaviour change principles, and daily gait retraining practice. Primary outcomes are proxy measures of medial knee joint load: knee adduction moment (early- and late-stance peaks and impulse), and varus thrust (presence/absence). Secondary outcomes include pain, physical function, medication and health care utilisation, quality of life, work ability, treatment blinding, intervention credibility and other biomechanical outcomes. Assessment timepoints are at baseline, six weeks (post intensive training), and three-months following the six-week intervention.

CONCLUSION

Our trial will determine whether toe-in or toe-out gait retraining is most effective at reducing proxy measures of medial knee joint load and varus thrust in people with medial knee osteoarthritis. This study will also evaluate if toe-in or toe-out gait retraining interventions are superior at improving pain, physical function and quality of life compared to placebo.

CLINICAL TRIAL REGISTRATION

This clinical trial protocol is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12621000414819).

Clinical and radiographic characterization of three-dimensional gait profiles of patients with knee osteoarthritis

BACKGROUND

Previous authors have utilized gait kinematics to categorize knee osteoarthritis patients into four distinct profiles: (1) flexed knee; (2) externally rotated knee; (3) stiff knee; and (4) knee varus thrust and rotational rigidity. However, the relationship between these gait profiles and patients' characteristics remains poorly understood. Thus, this study aimed to investigate whether differences in clinical and radiographic characteristics were associated with these four gait profiles.

METHODS

This cross-sectional study used available data from a previous biomechanical study. Data on the four gait profiles were collected from 42 patients with advanced knee osteoarthritis. Three-dimensional kinematics of the knee was recorded during gait using an optoelectronic system. Subjects were evaluated for knee strength, range of motion, tibial slope, femorotibial angle, radiographic severity, anthropometric measurements, and patient-reported outcomes. Multiple comparisons were made using Dunn's test. The level of significance was set at 5%, and the effect size was calculated.

FINDINGS

Body mass index (BMI) was the only variable associated with a specific gait profile: profile 4 (P = 0.01; effect size = P1 × P4: -0.62; P2 × P4: -0.41; P3 × P4: -0.40).

INTERPRETATION

Our findings suggest that most clinical and radiographic characteristics commonly measured in clinical practice did not differ significantly among knee osteoarthritis patients with the four different gait profiles. The only exception was a higher BMI noted in those with gait profile 4; however, it remains unclear whether it can cause varus thrust or rotation rigidity. The incorporation of three-dimensional motion analysis to identify gait profiles provided clinical insights beyond the limitations of traditional clinical assessments.

Fundamentals of osteoarthritis. Rehabilitation: Exercise, diet, biomechanics, and physical therapist-delivered interventions

Insights related to the pathogenesis of osteoarthritis (OA) have informed rehabilitative treatments that aim to mitigate the influence of several known impairments and risk factors for OA, with the goal to improve pain, function, and quality of life. The purpose of this invited narrative review is to provide fundamental knowledge to non-specialists about exercise and education, diet, biomechanical interventions, and other physical therapist-delivered treatments. In addition to summarizing the rationale for common rehabilitative therapies, we provide a synthesis of current core recommendations. Robust evidence based on randomized clinical trials supports exercise with education and diet as core treatments for OA. Structured, supervised exercise therapy is advised. The mode of exercise may vary but should be individualized. The dose should be based on an initial assessment, the desired physiological changes, and progressed when appropriate. Diet combined with exercise is strongly recommended and studies demonstrate a dose-response relationship between the magnitude of weight loss and symptom improvement. Recent evidence suggests the use of technology to remotely deliver exercise, diet and education interventions is cost-effective. Although several studies support the mechanisms for biomechanical interventions (e.g., bracing, shoe inserts) and physical therapist-delivered (passive) treatments (e.g., manual therapy, electrotherapeutic modalities) fewer rigorous randomized trials support their clinical use; these therapies are sometimes recommended as adjuncts to core treatments. The mechanisms of action for all rehabilitative interventions include contextual factors such as attention and placebo effects. These effects can challenge our interpretation of treatment efficacy from clinical trials, yet also provide opportunities to maximize patient outcomes in clinical practice. When evaluating rehabilitative interventions, the field may benefit from increased emphasis on research that considers contextual factors while evaluating mechanistic, longer-term, clinically-important and policy-relevant outcome measures.

A comparison of stiffness of six knee braces with application for posterolateral corner reconstructions

Posterolateral corner knee injuries are clinically significant, and often require surgical reconstruction. The optimal knee brace following posterolateral corner reconstructions has not yet been determined via clinical nor biomechanical study. We sought to evaluate the stiffness of six types of knee braces to determine the ideal brace type for reducing varus forces, which may have clinical utility for posterolateral corner knee reconstruction rehabilitation. Six different groups of knee braces underwent mechanical testing: cruciate braces, cruciate braces with a valgus bend, medial unloaders, articulating sleeves, hinged braces, and tri-panel immobilizers. Each brace was fitted to the same fiberglass leg model and was secured to the testing apparatus. Force was applied under four-point bending to generate a varus moment about the artificial knee. The stiffness in Newtons per millimeter (N/mm) of each brace was calculated from the slope of the force-displacement curve. The cruciate brace with a valgus bend had the highest average stiffness at 192.61 N/mm (SD 28.53). The articulating sleeve was the least stiff with an average stiffness of 49.86 N/mm (SD 8.99). Stiffness of the cruciate brace was not statistically different compared to cruciate valgus (p = 0.083) or medial unloader (p = 0.098). In this experimental design, a cruciate brace with a valgus bend was shown to have the highest overall stiffness, while an articulating sleeve had the lowest stiffness. Future work will investigate whether this translates into clinical performance.

Combined Rehabilitation Protocol in the Treatment of Osteoarthritis of the Knee: Comparative Study of Extremely Low-Frequency Magnetic Fields and Soft Elastic Knee Brace Effect

The investigation of this observational case-control study aimed at determining the effectiveness of a combined treatment of extremely low-frequency electromagnetic fields (ELF) with a soft elastic knee brace versus ELF alone in knee osteoarthritis (KOA) with respect to a reduction in pain and functional recovery. We hypothesized that the combined use of ELF and a soft elastic knee brace may provide better results. Thirty-five patients (N = 35, divided into Group 1 = ELF and Group 2 = ELF with the soft elastic knee brace) were analyzed. The rehabilitative protocol consisted of 10 sessions of antiphlogistic and antiedema programs (first cycle) for 2 weeks, followed by twelve sessions of bone repair and connective tissue repair programs (second cycle) in patients with knee osteoarthritis (KOA) for 4 weeks. Patient evaluations were conducted at baseline (T0) and after 2 (T1) and 4 (T2) weeks of treatment. A follow-up evaluation was conducted 6 weeks after treatment (T3). The LIMFA© Therapy System was used to create multifrequency magnetoelectric fields with an intensity of 100 µT and a low-frequency field. The Incrediwear Cred 40 knee sleeve (Incred) was used for alleviating knee pain. The Visual Analogue Scale (VAS), the Knee Injury and Osteoarthritis Outcome Score (KOOS), and the Lysholm score (Ls) were used as outcome measures. The results showed that pain at rest (Vr), pain in motion (Vm), KOOS, and Ls were significantly affected by ELF over time. In conclusion, Group 2 had a better response in terms of pain resolution at rest (p < 0.05) and a concurrent better response at T3 in terms of functional recovery (p < 0.05).

Exploring the modification factors of exercise therapy on biomechanical load in patients with knee osteoarthritis: a systematic review and meta-analysis

The objective of this systematic review and meta-analysis is to clarify the effect of exercise therapy on the first peak knee adduction moment (KAM), as well as other biomechanical loads in patients with knee osteoarthritis (OA), and identify physical characteristics that influence differences in biomechanical load after exercise therapy. The data sources are PubMed, PEDro, and CINAHL, from study inception to May 2021. The eligibility criteria include studies evaluating the first peak (KAM), peak knee flexion moment (KFM), maximal knee joint compression force (KCF), or co-contraction during walking before and after exercise therapy in patients with knee OA. The risk of bias was independently assessed by two reviewers using PEDro and NIH scales. Among 11 RCTs and nine non-RCTs, 1119 patients with knee OA were included (average age: 63.7 years). As the results of meta-analysis, exercise therapy tended to increase the first peak KAM (SMD 0.11; 95% CI: -0.03-0.24), peak KFM (SMD 0.13; 95% CI: -0.03-0.29), and maximal KCF (SMD 0.09; 95% CI -0.05-0.22). An increased first peak KAM was significantly associated with a larger improvement in knee muscle strength and WOMAC pain. However, the quality of evidence regarding the biomechanical loads was low-to-moderate according to the GRADE approach. The improvement in pain and knee muscle strength may mediate the increase in first peak KAM, suggesting difficulty in balancing symptom relief and biomechanical load reduction. Therefore, exercise therapy may satisfy both aspects simultaneously when combined with biomechanical interventions, such as a valgus knee brace or insoles. Registration: PROSPERO (CRD42021230966).

Evaluating the effective pressure applied by a valgus knee orthosis in individuals with medial knee osteoarthritis based on the dose-response relationship

BACKGROUND

There is evidence that valgus knee orthosis improves clinical and biomechanical outcomes in individuals with medial knee osteoarthritis (MKOA). It is unclear whether variations in pressure application by orthosis straps can affect the biomechanical outcomes. This study aimed to determine the dose-response relationship between different orthosis straps tensions and changes in knee adduction moment (KAM) parameters in individuals with MKOA.

METHOD

Twenty-four individuals with symptomatic MKOA were enrolled in this quasi-experimental study. Five tension conditions in orthosis straps were tested in 20-mmHg increments, from 0 (no pressure) to 100 (maximal pressure) mmHg. Patients were asked to adjust the orthosis strap tension based on their perceived comfort. After each condition, a 3D gait analysis was performed, and KAM parameters were calculated. The participants also reported their satisfaction with knee orthosis adjustment for each pressure condition.

RESULTS

With successive increases in strap tension from 40 to 80 mmHg, the first peak, second peak, and angular impulse of KAM decreased nonlinearly (from 6 % to 25 %). Increasing the orthosis strap tension to 100 mmHg significantly decreased (P < 0.05) the participants' satisfaction level. The effective dosages (IC₅₀) of pressure for the first peak, second peak, and angular impulse of KAM as responses were 58, 65, and 69 mmHg, respectively.

CONCLUSION

The KAM decline was not linear as the strap pressure increased. Patients were dissatisfied with orthosis adjustment when strap tension was above 80 mmHg. The optimum dosage of pressure on the knee joint's lateral side for adjusting an orthosis' strap tension is approximately 69 mmHg.

Knee adduction moment decomposition: Toward better clinical decision-making

Knee adduction moment (KAM) is correlated with the progression of medial knee osteoarthritis (OA). Although a generic gait modification can reduce the KAM in some patients, it may have a reverse effect on other patients. We proposed the "decomposed ground reaction vector" (dGRV) model to 1) distinguish between the components of the KAM and their contribution to the first and second peaks and KAM impulse and 2) examine how medial knee OA, gait speed, and a brace influence these components. Using inverse dynamics as the reference, we calculated the KAM of 12 healthy participants and 12 patients with varus deformity and medial knee OA walking with/without a brace and at three speeds. The dGRV model divided the KAM into four components defined by the ground reaction force (GRF) and associated lever arms described with biomechanical factors related to gait modifications. The dGRV model predicted the KAM profile with a coefficient of multiple correlations of 0.98 ± 0.01. The main cause of increased KAM in the medial knee OA group, the second component (generated by the vertical GRF and mediolateral distance between the knee and ankle joint centers), was decreased by the brace in the healthy group. The first peak increased, and KAM impulse decreased with increasing velocity in both groups, while no significant change was observed in the second peak. The four-component dGRV model successfully estimated the KAM in all tested conditions. It explains why similar gait modifications produce different KAM reductions in subjects. Thus, more personalized gait rehabilitation, targeting elevated components, can be considered.

Relationship Between Knee Biomechanics and Pain in People With Knee Osteoarthritis: A Systematic Review and Meta-Analysis

OBJECTIVE

Our primary aim was to determine the cross-sectional relationship between knee biomechanics during gait and pain in people with medial knee osteoarthritis. Our secondary aim was to evaluate differences in knee biomechanics between symptomatic and asymptomatic participants with medial knee osteoarthritis.

METHODS

Four online databases were searched from inception to July 2021. Eligible studies included people with medial/nonspecific knee osteoarthritis and a reported relationship between knee biomechanics during gait and pain or biomechanics of symptomatic and asymptomatic participants. Two reviewers independently extracted data and evaluated risk of bias. Random-effects meta-analyses were performed when three or more studies reported the same biomechanical variable for pooling (knee adduction moment [KAM], KAM impulse, varus thrust, and peak knee flexion moment [KFM]).

RESULTS

Forty studies were included. Methodological quality ranged from 4 to 9/10. Forty-seven unique biomechanical variables were reported. For the KAM, there was no correlation with pain for peak values pooled (early stance and overall) (r = 0.00, 95% confidence interval [95% CI]: -0.12, 0.11, k = 16), a small negative correlation for early stance peak alone (r = -0.09, 95% CI -0.18, -0.002, k = 12), and a medium positive correlation for the overall peak during stance (r = 0.30, 95% CI 0.17, 0.42, k = 4). Metaregression identified that body mass index moderated the peak KAM-pain relationship (P < 0.001). KAM impulse had a small positive correlation with pain (r = 0.23, 95% CI 0.04, 0.40, k = 5), and people with varus thrust had 3.84 greater odds of reporting pain compared with people without (95% CI 1.72, 8.53, k = 3). Meta-analyses for the peak KFM and pain correlation and secondary aim were nonsignificant.

CONCLUSION

Some knee gait biomechanics were associated with pain in this cohort. Longitudinal studies are required to determine causality.

Effect of a valgus brace on medial tibiofemoral joint contact force in knee osteoarthritis with varus malalignment: A within-participant cross-over randomised study with an uncontrolled observational longitudinal follow-up

Background

Previous investigations on valgus knee bracing have mostly used the external knee adduction moment. This is a critical limitation, as the external knee adduction moment does not account for muscle forces that contribute substantially to the medial tibiofemoral contact force (MTCF) during walking. The aims of this pilot study were to: 1) determine the effect of a valgus knee brace on MTCF; 2) determine whether the effect is more pronounced after 8 weeks of brace use; 3) assess the feasibility of an 8-week brace intervention.

Methods

Participants with medial radiographic knee OA and varus malalignment were fitted with an Össur Unloader One^© brace. Participants were instructed to wear the brace for 8 weeks. The MTCF was estimated via an electromyogram-assisted neuromuscular model with and without the knee brace at week 0 and week 8. Feasibility outcomes included change in symptoms, quality of life, confidence, acceptability, adherence and adverse events.

Results

Of the 30 (60% male) participants enrolled, 28 (93%) completed 8-week outcome assessments. There was a main effect of the brace (p<0.001) on peak MTCF and MTCF impulse, but no main effect for time (week 0 and week 8, p = 0.10), and no interaction between brace and time (p = 0.62). Wearing the brace during walking significantly reduced the peak MTCF (-0.05 BW 95%CI [-0.10, -0.01]) and MTCF impulse (-0.07 BW.s 95%CI [-0.09, -0.05]). Symptoms and quality of life improved by clinically relevant magnitudes over the 8-week intervention. Items relating to confidence and acceptability were rated relatively highly. Participants wore the brace on average 6 hrs per day. Seventeen participants reported 30 minor adverse events over an 8-week period.

Conclusion

Although significant, reductions in the peak MTCF and MTCF while wearing the knee brace were small. No effect of time on MTCF was observed. Although there were numerous minor adverse events, feasibility outcomes were generally favourable.

Trial registration

Australian and New Zealand Clinical Trials Registry (12619000622101).

Effectiveness of gait retraining interventions in individuals with hip or knee osteoarthritis: A systematic review and meta-analysis

BACKGROUND

Osteoarthritis is a chronic synovial joint disease leading to pain, stiffness, and gait dysfunction, resulting in a significant health and economic burden. Gait retraining strategies and tools are used to address biomechanical gait dysfunction and symptoms in individuals with osteoarthritis. However, there is limited evidence relating to their effectiveness.

QUESTION

Do gait retraining strategies and tools improve gait biomechanics and symptoms in individuals with hip or knee osteoarthritis compared to control or alternate intervention?

METHODS

Seven databases were searched using key words relating to osteoarthritis, gait retraining, and biomechanics. A best evidence synthesis was conducted on included studies. Where available, a meta-analysis was performed, and the standardised mean difference (SMD) and 95% confidence internals (CI) were reported.

RESULTS

Eighteen studies were included. One study investigated gait retraining in participants with hip osteoarthritis and demonstrated limited evidence for improving gait biomechanics. Seventeen studies on knee osteoarthritis were included in the best evidence synthesis with six included in the meta-analysis. Gait retraining strategies which incorporated a real-time biofeedback tool, appear to have strong evidence for effectively modifying walking biomechanics. Moderate evidence was identified to support kinesiology taping improving pain scores. The meta-analysis pooled effect demonstrated significant improvements for knee adduction moment [SMD, -1.10; 95% CI. -1.85, -0.35] and the Western Ontario and McMaster Osteoarthritis Index in favour of gait retraining than a control intervention [SMD, -0.86; 95% CI. -1.33, -0.39]. All other interventions demonstrated evidence that was conflicting, limited, or not in favour of gait retraining.

CONCLUSION

Gait retraining may be beneficial for improving biomechanics and symptoms in knee osteoarthritis, however due to the high heterogeneity and limited studies in the analysis, further research is required. Further high quality randomised controlled trials for knee and especially hip osteoarthritis investigating the effects of gait retraining on biomechanics and symptoms are required.

Biomechanical Effect of Valgus Knee Braces on the Treatment of Medial Gonarthrosis: A Systematic Review

Background

Valgus braces are prescribed as a common conservative treatment option for patients with medial gonarthrosis to improve their quality of life. Many studies had reviewed the effects of the valgus braces on patients with medial gonarthrosis, while they mainly focused on the knee adduction moment (KAM), with less attention paid to other parameters such as spatiotemporal and morphological parameters.

Objectives

The purpose of this study was to review the effects of valgus braces on the spatiotemporal, kinematic/kinetic, morphological, and muscle parameters.

Methods

Based on the selected keywords, a survey of literatures was performed in Web of Science, PubMed, Scopus, and Google Scholar using the PRISMA methods, and the search period was established from January 2000 to March 2022.

Results

Thirty-four articles were included. According to the conclusion of these articles, the valgus brace can be used to relieve the symptoms of patients with medial gonarthrosis by decreasing the varus angle, decreasing the KAM, and redistributing the knee compartment loads. However, the effects of valgus braces on other biomechanical parameters (e.g., walking speed, cadence, joint angle, and joint space) had not reached a consensus.

Conclusions

The valgus knee brace can effectively relieve the symptoms of medial gonarthrosis through multiple mechanisms, while there is still some confusion about the effectiveness of the valgus brace on the other biomechanical parameters.

Conservative Trio-Therapy for Varus Knee Osteoarthritis: A Prospective Case-Study

Background and Objectives: Knee osteoarthritis (OA) is a frequent cause of pain, functional limitations, and a common reason for surgical treatment, such as joint replacement. Conservative therapies can reduce pain and improve function; thus, delaying or even preventing surgical intervention. Various individual conservative therapies show benefits, but combination therapies remain underexplored. The aim of this prospective case-study was to assess the effect of a conservative combination therapy in patients with painful varus knee OA. Materials and Methods: With strong inclusion and exclusion criteria, nine patients with painful varus knee OA (mean age 56 years (range 51−63 years) were selected and monitored over six months, using the following clinical outcome scores: pain visual analog scale (VAS), Western Ontario and McMaster Universities osteoarthritis index (WOMAC score), short-form−36 items (SF-36) quality of life score, and the sports frequency score. All patients received a standardized conservative trio-therapy with varus-reducing hindfoot shoe-insoles with a lateral hindfoot wedge, oral viscosupplementation, and physiotherapy for six months. Results: The pain was reduced significantly from initial VAS values of 5.4 points (range, 3−10) to values of 0.6 points (range, 0−3; p < 0.01), at the end of treatment. After six months, seven out of nine patients reported no pain at all (VAS 0). The WOMAC score improved significantly, from initial values of 35 (range, 10−56) to values of 2 (range, 0−9; p < 0.01). The SF-36 score showed significant improvement after six months in all four domains of physical health (p < 0.01) and in two of the four domains of mental health (p < 0.05). The sports frequency score increased by at least one level in six out of nine patients after six months. Conclusions: The conservative trio-therapy in patients with varus knee OA showed positive initial clinical results: less pain, higher function, better quality of life, and higher sport activity. Further studies are required to evaluate the long-term effect.

Alternatives to Knee Braces

Knee braces continue to be a widely utilized piece of medical equipment, ranging from simple over the counter sleeves to more complex functional braces, with the ability to provide electrical stimulation to muscle groups. Despite their popularity, alternatives to knee braces exist for patients who find braces to be ineffective, uncomfortable, cumbersome, or overly expensive. While high-quality studies are lacking for modalities such as neoprene sleeves, compression stockings, and kinesiotaping, there is promising evidence that these interventions can confer an element of stability and pain relief for a variety of knee pathologies both with regard to acute and chronic injuries as well as in the postoperative rehabilitation period. While no "holy grail" exists for the ideal brace, or bracing alternative, it is important for providers to be aware of the options available to patients as well as the current evidence for these various modalities, so that the provider can best guide musculoskeletal care.

Free-Living User Perspectives on Musculoskeletal Pain and Patient-Reported Mobility With Passive and Powered Prosthetic Ankle-Foot Components: A Pragmatic, Exploratory Cross-Sectional Study

Introduction

Studies with a powered prosthetic ankle-foot (PwrAF) found a reduction in sound knee loading compared to passive feet. Therefore, the aim of the present study was to determine whether anecdotal reports on reduced musculoskeletal pain and improved patient-reported mobility were isolated occurrences or reflect a common experience in PwrAF users.

Methods

Two hundred and fifty individuals with transtibial amputation (TTA) who had been fitted a PwrAF in the past were invited to an online survey on average sound knee, amputated side knee, and low-back pain assessed with numerical pain rating scales (NPRS), the PROMIS Pain Interference scale, and the PLUS-M for patient-reported mobility in the free-living environment. Subjects rated their current foot and recalled the ratings for their previous foot. Recalled scores were adjusted for recall bias by clinically meaningful amounts following published recommendations. Statistical comparisons were performed using Wilcoxon's signed rank test.

Results

Forty-six subjects, all male, with unilateral TTA provided data suitable for analysis. Eighteen individuals (39%) were current PwrAF users, whereas 28 subjects (61%) had reverted to a passive foot. After adjustment for recall bias, current PwrAF users reported significantly less sound knee pain than they recalled for use of a passive foot (−0.5 NPRS, p = 0.036). Current PwrAF users who recalled sound knee pain ≥4 NPRS with a passive foot reported significant and clinically meaningful improvements in sound knee pain (−2.5 NPRS, p = 0.038) and amputated side knee pain (−3 NPRS, p = 0.042). Current PwrAF users also reported significant and clinically meaningful improvements in patient-reported mobility (+4.6 points PLUS-M, p = 0.016). Individuals who had abandoned the PwrAF did not recall any differences between the feet.

Discussion

Current PwrAF users reported significant and clinically meaningful improvements in patient-reported prosthetic mobility as well as sound knee and amputated side knee pain compared to recalled mobility and pain with passive feet used previously. However, a substantial proportion of individuals who had been fitted such a foot in the past did not recall improvements and had reverted to passive feet. The identification of individuals with unilateral TTA who are likely to benefit from a PwrAF remains a clinical challenge and requires further research.

Relationship between radiographic measurements and knee adduction moment using 3D gait analysis

BACKGROUND

Radiographic factors estimate the state of the static knee joint, and it is questionable how well these parameters reflect the dynamic knee condition. The external knee adduction moment (KAM) during gait is known to be a kinetic variable contributing to osteoarthritis progression. This study aims to investigate the effects of static radiographic parameters on the dynamic KAM during gait.

METHODS

Overall, 123 patients (mean age, 65.7 years; standard deviation, 8.1 years; 34 men and 89 women) were included. Seven radiographic parameters including the mechanical tibiofemoral angle (mTFA), Kellgren-Lawrence grade, and ankle joint line orientation (AJLO) were measured on radiographs, and the maximum KAM and KAM-time integral in the stance phase were obtained using three-dimensional gait analysis. The correlation and multiple regression analyses were performed for identifying significant radiographic measurements associated with the KAM.

RESULTS

Most of the radiographic measurements correlated with the maximum KAM and KAM-time integral. As a result of multiple regression analysis, the mTFA (p < 0.001) and AJLO (p = 0.003) were identified as significant factors associated with the KAM-time integral (R² = 0.450); the mTFA (p < 0.001) and AJLO (p = 0.003) were identified as a significant factor associated with the maximum KAM (R² = 0.352) in multiple regression analysis. The discriminant validity of KAM was highest at varus 5.7 degree of the mTFA and 7.5 degree of the AJLO.

SIGNIFICANCE

The mTFA and AJLO were significantly associated with the KAM. However, to be used as a surgical indication for corrective osteotomy, a longitudinal study is needed to validate whether the mTFA and AJLO values directly cause osteoarthritis progression as we have suggested.

LEVEL OF EVIDENCE

III.

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.

Are there different gait profiles in patients with advanced knee osteoarthritis? A machine learning approach

BACKGROUND

Determine whether knee kinematics features analyzed using machine-learning algorithms can identify different gait profiles in knee OA patients.

METHODS

3D gait kinematic data were recorded from 42 patients (Kellgren-Lawrence stages III and IV) walking barefoot at individual maximal gait speed (0.98 ± 0.34 m/s). Principal component analysis, self-organizing maps, and k-means were applied to the data to identify the most relevant and discriminative knee kinematic features and to identify gait profiles.

FINDINGS

Four different gait profiles were identified and clinically characterized as type 1: gait with the knee in excessive varus and flexion (n = 6, 14%, increased knee adduction and increased maximum and minimum knee flexion, p < 0.01); type 2: gait with knee external rotation, either in varus or valgus (n = 11, 26%, excessive maximum and minimum external rotation, p < 0.001); type 3: gait with a stiff knee (n = 17, 40%, decreased knee flexion range of motion, p < 0.001); and type 4: gait with knee varus 'thrust' and decreased rotation (n = 8, 19%, increased and reduced range of motion in the coronal and transverse plane, respectively, p < 0.05).

INTERPRETATION

In a group of patients with homogeneous Kellgren-Lawrence classification of knee OA, gait kinematics data permitted to identify four different gait profiles. These gait profiles can be a valuable tool for helping surgical decisions and treatment. To allow generalization, further studies should be carried with a larger and heterogeneous population.

Effectiveness, safety, and cost-utility of a knee brace in medial knee osteoarthritis: the ERGONOMIE randomized controlled trial

OBJECTIVE

This pragmatic, multicenter, open-label, randomized controlled trial (RCT) aimed to compare the effectiveness, safety, and cost-utility of a custom-made knee brace versus usual care over 1 year in medial knee osteoarthritis (OA).

DESIGN

120 patients with medial knee OA (VAS pain at rest >40/100), classified as Kellgren-Lawrence grade II-IV, were randomized into two groups: ODRA plus usual care (ODRA group) and usual care alone (UCA group). The primary effectiveness outcome was the change in VAS pain between M0 and M12. Secondary outcomes included changes over 1 year in KOOS (function) and OAKHQOL (quality of life) scores. Drug consumption, compliance, safety of the knee brace, and cost-utility over 1 year were also assessed.

RESULTS

The ODRA group was associated with a higher improvement in: VAS pain (adjusted mean difference of -11.8; 95% CI: -21.1 to -2.5); all KOOS subscales (pain: +8.8; 95% CI: 1.4-16.2); other symptoms (+10.4; 95% CI: 2.7-18); function in activities of daily living (+9.2; 95% CI: 1.1-17.2); function in sports and leisure (+12.3; 95% CI: 4.3-20.3); quality of life (+9.9; 95% CI: 0.9-15.9), OAKHQOL subscales (pain: +14.8; 95% CI: 5.0-24.6); and physical activities (+8.2; 95% CI: 0.6-15.8), and with a significant decrease in analgesics consumption at M12 compared with the UCA group. Despite localized side-effects, observance was good at M12 (median: 5.3 h/day). The ODRA group had a more than 85% chance of being cost-effective for a willingness-to-pay threshold of €45 000 per QALY.

CONCLUSIONS

The ERGONOMIE RCT demonstrated significant clinical benefits of an unloader custom-made knee brace in terms of improvements in pain, function, and some aspects of quality of life over 1 year in medial knee OA, as well as its potential cost-utility from a societal perspective.

Shoe-stiffening inserts for first metatarsophalangeal joint osteoarthritis: a randomised trial

OBJECTIVE

To evaluate the efficacy of carbon-fibre shoe-stiffening inserts in individuals with first metatarsophalangeal joint osteoarthritis.

DESIGN

This was a randomised, sham-controlled, participant- and assessor-blinded trial. One hundred participants with first metatarsophalangeal joint osteoarthritis received rehabilitation therapy and were randomised to receive either carbon fibre shoe-stiffening inserts (n = 49) or sham inserts (n = 51). The primary outcome measure was the Foot Health Status Questionnaire (FHSQ) pain domain assessed at 12 weeks.

RESULTS

All 100 randomised participants (mean age 57.5 (SD 10.3) years; 55 (55%) women) were included in the analysis of the primary outcome. At the 12 week primary endpoint, there were 13 drop-outs (7 in the sham insert group and 6 in the shoe-stiffening insert group), giving completion rates of 86 and 88%, respectively. Both groups demonstrated improvements in the FHSQ pain domain score at each follow-up period, and there was a significant between-group difference in favour of the shoe-stiffening insert group (adjusted mean difference of 6.66 points, 95% CI 0.65 to 12.67, P = 0.030). There were no between-group differences for the secondary outcomes, although global improvement was more common in the shoe-stiffening insert group compared to the sham insert group (61 vs 34%, RR 1.73, 95% CI 1.05 to 2.88, P = 0.033; number needed to treat 4, 95% CI 2 to 16).

CONCLUSION

Carbon-fibre shoe-stiffening inserts were more effective at reducing foot pain than sham inserts at 12 weeks. These results support the use of shoe-stiffening inserts for the management of this condition, although due to the uncertainty around the effect on the primary outcome, some individuals may not experience a clinically worthwhile improvement.

Biomechanical Study of a Tricompartmental Unloader Brace for Patellofemoral or Multicompartment Knee Osteoarthritis

Objective: Off-loader knee braces have traditionally focused on redistributing loads away from either the medial or lateral tibiofemoral (TF) compartments. In this article, we study the potential of a novel "tricompartment unloader" (TCU) knee brace intended to simultaneously unload both the patellofemoral (PF) and TF joints during knee flexion. Three different models of the TCU brace are evaluated for their potential to unload the knee joint. Methods: A sagittal plane model of the knee was used to compute PF and TF contact forces, patellar and quadriceps tendon forces, and forces in the anterior and posterior cruciate ligaments during a deep knee bend (DKB) test using motion analysis data from eight participants. Forces were computed for the observed (no brace) and simulated braced conditions. A sensitivity and validity analysis was conducted to determine the valid output range for the model, and Statistical Parameter Mapping was used to quantify the effectual region of the different TCU brace models. Results: PF and TF joint force calculations were valid between ~0 and 100 degrees of flexion. All three simulated brace models significantly (p < 0.001) reduced predicted knee joint loads (by 30-50%) across all structures, at knee flexion angles >~30 degrees during DKB. Conclusions: The TCU brace is predicted to reduce PF and TF knee joint contact loads during weight-bearing activity requiring knee flexion angles between 30 and 100 degrees; this effect may be clinically beneficial for pain reduction or rehabilitation from common knee injuries or joint disorders. Future work is needed to assess the range of possible clinical and prophylactic benefits of the TCU brace.

Different Prevention and Treatment Strategies for Knee Osteoarthritis (KOA) with Various Lower Limb Exoskeletons – A Comprehensive Review

It was reported that about 10% of people suffer from painful knee arthritis, and a quarter of them were severely disabled. The core activities of daily living were severely limited by knee osteoarthritis (KOA). In order to reduce knee pain and prolong the life of the knee joint, there has been an increasing demand on the development of exoskeletons, for prevention and treatment. The course of KOA was closely related to the biomechanics of knee joint, and the pathogenesis was summarized based on the biomechanics of knee joint. For the prevention and clinical treatment, exoskeletons are classified into three categories: prevention, treatment, and rehabilitation after the operation. Furthermore, the design concepts, actuators, sensors, control strategies, and evaluation criteria were presented. Finally, the shortcomings and limitations were summarized. It is useful for researchers to develop suitable exoskeletons in the future.

The Effects of Knee Orthosis with Two Degrees of Freedom Joint Design on Gait and Sit-to-Stand Task in Patients with Medial Knee Osteoarthritis

Objectives

Knee bracing as a conservative treatment option for patients with medial knee osteoarthritis (KOA) is of great interest to health practitioners and patients alike. Optimal orthotic knee joint structure is essential to achieve biomechanical and clinical effectiveness. Therefore, this study aimed to identify the effects of a knee orthosis with a new two-degrees-of-freedom (DOF) joint design on selected gait parameters and in a sit-to-stand task in patients with mild-to-moderate medial KOA.

Methods

This study was conducted both at the Physical Medicine and Rehabilitation Clinic in Shahid Modarres Academic Hospital and the Biomechanical Laboratory of Rehabilitation Faculty of Iran University of medical Sciences in Tehran, Iran from September 2015 to October 2017. The gait performance of 16 patients was assessed without an orthosis, using a common one-DOF (DOF) knee orthosis and using the same knee orthosis with a two-DOF orthotic joint design. The interactive shearing force between limb and brace in the shell area during a sit-to-stand test was also identified. Repeated measures analysis of variance was used to analyse the data.

Results

Compared with walking with no orthosis, both orthosis conditions reduced the external knee adduction moment significantly (P ≤0.05). A significant increase between the one-DOF and two-DOF conditions in terms of walking speed (P = 0.041 and P = 0.009, respectively) and stride length (P = 0.028 and P = 0.038, respectively) was observed. In a sit-to-stand test, wearing the orthosis significantly decreased knee transverse plane range of motion (P ≤0.05). There was a 41.31 ± 8.34 Newtons reduction in knee flexion constraint force.

Conclusion

The two-DOF knee orthosis was more comfortable compared to the one-DOF knee orthosis during deep knee flexion. Otherwise, the one-DOF- and two-DOF-braces performed similarly.

Comparing walking biomechanics of older females in maximal, minimal, and traditional shoes

BACKGROUND

Knee osteoarthritis (OA) is a degenerative joint disease that affects millions of individuals each year. Several biomechanical variables during walking have been identified as risk factors for developing knee OA, including the peak external knee adduction moment (KAM) and the knee flexion angle at initial contact. Many interventions have been studied to help mitigate these risk factors, including footwear. However, it is largely unknown how varying shoe cushioning may affect walking biomechanics related to knee OA risk.

RESEARCH QUESTION

What is the effect of maximally and minimally cushioned shoes on walking biomechanics compared to a traditionally cushioned shoe in older females?

METHODS

Walking biomechanics in three shoes (maximal, traditional, minimal) were collected on 16 healthy females ages 50-70 using an 8-camera 3D motion capture system and two embedded force plates. Key biomechanical variables related to knee OA disease risk were compared between shoes using repeated measures ANOVAs.

RESULTS

The KAM was significantly larger in the maximal shoe (p = 0.005), while the knee flexion angle at initial contact was significantly larger in both the maximal and minimal shoe compared to the traditional shoe (p = .000). Additionally, the peak knee flexion angle (p = .000) and the loading rates of the vertical ground reaction force were (instantaneous: p = 0.001; average: p = .010) were significantly higher in the minimal shoe.

SIGNIFICANCE

While these results are specific to the shoes used in this study, clinicians should exercise caution in prescribing maximal or minimal shoes to females in this age group who may be at risk of knee OA given these results. Research is needed on the effect of these shoes in patients with knee OA.

The effect of a knee brace in dynamic motion-An instrumented gait analysis

Background

Osteoarthritis (OA) is a common problem in the older population. To reduce pain and stress in the affected knee joint compartment, a functional knee brace is often prescribed by physicians to protect it from high loads.

Objectives

An instrumented gait analysis should evaluate how the 4-point knee orthosis for varus or valgus load relief (M.4s OA) changes the kinematics of the knee, especially in the frontal plane.

Methods

17 healthy participants took part and were analyzed with an inertial sensor system (MyoMotion) giving continuous, objective information on the anatomical angles. The measurements were made both without wearing a knee brace and with the brace in different settings.

Results

The results show a significant reduction in the maximum knee abduction and raised knee adduction. The knee brace, with a strong adjustment in varus or valgus orientation, caused a shift of maximum ab-/adduction in the proposed direction in 69% and 75% of the dynamic tests, respectively. The knee motion in the frontal plane shows individual movement patterns.

Conclusion

The use of the brace leads to significant changes in the knee’s movement. Patient-specific movement patterns may explain different effects of functional knee braces on individual persons. Inertial sensors have been shown to be a low-cost, easy-to-use option for individual movement analysis and further personalized therapy.

Valgus knee bracing may have no long-term effect on pain improvement and functional activity in patients with knee osteoarthritis: a meta-analysis of randomized trials

Background

Knee osteoarthritis (KOA), with a high incidence in old-age population, adversely affects their life quality. The valgus knee bracing is an important physical therapy for KOA, but its clinical effects on pain release and functional improvement remained unclear. This meta-analysis is to systematically evaluate the clinical outcomes of valgus knee bracing in patients with KOA.

Methods

A meta-analysis of clinical randomized controlled trials (RCTs) on pain and functional changes in patients with KOA after using valgus knee braces. The search period was ranged from the inception of the database to May 2020. The enrolled research databases included PubMed, Embase, and Web of Science databases. Two investigators independently formulated inclusion criteria and exclusion criteria and screened and determined the final enrolled literature. Then the outcome indicators were extracted and organized from the included literature, and the risk of bias was assessed by Cochrane Handbook 5.0.1.

Results

A total of 10 articles were included in this study, including 739 patients. Eight articles were related to the visual analog scale (VAS) pain score, and the results showed that RR = − 0.29, 95% CI − 0.73, 0.15], P = 0.20; four articles were related to the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) function score, and the results showed that RR = − 0.15, 95% CI [− 0.41, 0.11], P = 0.26; two articles were related to the Knee Injury and Osteoarthritis Outcome Score (KOOS), and the results showed that RR = 0.58, 95% CI [− 4.25, 5.42], P = 0.81; and three articles were related to the KOOS Activities of Daily Living (KOOS-ADL), and the results showed that RR = 0.04, 95% CI [− 0.62, 0.69], P = 0.91. These results indicated that the valgus knee bracing has no statistical significance in pain and functional activity improvement of patients with KOA. The subgroup analysis showed that the follow-up time was the source of the heterogeneity of the VAS pain score.

Conclusion

Our current evidence suggests that valgus knee bracing may not improve pain release and function activates in KOA patients in the long-term period, but only being beneficial to the short-term rehabilitation.

A method for quantitative evaluation of a valgus knee orthosis using biplane x-ray images

Knee orthoses are designed to reestablish the normal kinematics of the knee joint. However, the data on the effectiveness of them on modifying the internal joint kinematics are scarce. The aim of this study was to develop a method to allow accurate comparison of the knee contact kinematics in osteoarthritic (OA) subjects with and without wearing a valgus knee orthosis using imaging techniques. Biplane x-ray images of a subject (68 yrs., female, 1.70 m, 89 kg, left knee) was recorded during a weight-bearing squat at five positions. The same squat trial was repeated while wearing the orthosis. The 3D models of the knee were reconstructed from the biplane x-rays and the joint kinematics as well as the tibiofemoral contact point locations and bone-to-bone distance were compared at each posture. This could be seen as a proof of concept for the use of contact point locations as a parameter for evaluating the effectiveness of knee orthoses.Clinical Relevance- Joint kinematics derived from the skin markers suffer from low accuracy. The real impact of the knee orthoses on the skeleton takes vigorous techniques, which allows detecting the subtle kinematics changes directly at the joint level.

[Insoles, knee braces and ankle-foot orthoses in the treatment of medial gonarthrosis : A literature review]

BACKGROUND

Osteoarthritis is the most common joint disease worldwide and mostly affects the knee joint (gonarthrosis). In treatment algorithms, technical aids in the form of laterally wedged insoles, valgizing knee braces and ankle-foot orthoses have an importance in the treatment of medial unicompartmental knee joint disease. However, national and international guidelines differ in their recommendations.

INSOLES

Taking into account a great amount of scientific work, the measurable effect of laterally wedged insoles appears to be low, so that a justifying indication only exists at low gonarthrosis levels.

KNEE BRACES

Valgizing knee braces have shown stronger biomechanical and clinical effects, but with a slightly increased complication potential and low compliance. Low to medium-grade arthrosis can be treated.

ANKLE-FOOT ORTHOSES

Ankle-foot arthroses have not yet been conclusively examined. Initial work indicates biomechanical and clinical efficacy. The overall effects and indications appear comparable to knee braces, probably with less complication potential.

The Relationship between Knee Adduction Moment and Knee Osteoarthritis Symptoms according to Static Alignment and Pelvic Drop

Objectives

To investigate the relationship between external knee adduction moment (KAM) and knee osteoarthritis (OA) symptoms according to static alignment and pelvic drop.

Methods

Ninety-five participants with symptomatic knee OA were included. Radiographic severity was graded by Kellgren and Lawrence (KL) scale. The hip-knee-ankle (HKA) angle was used to assess limb alignment from a full-length lower-limb radiograph. KAM-related variables (peak KAM and KAM impulse) and pelvic drop angle were determined from 3D gait analysis. Symptoms were assessed via visual analog scale (VAS) for pain and hospital for special surgery (HSS) score for physical function. The relationship between KAM and symptoms was evaluated according to radiographic severity and pelvic drop using linear models.

Results

According to the more affected knee in the varus group, both the two KAM-related measures (peak KAM and KAM impulse) were positively associated with greater VAS pain and were negatively associated with HSS score. Only peak KAM was correlated with VAS and HSS in the valgus group. VAS pain score of the more affected knee was positively correlated with pelvic drop angle. Stratified by pelvic drop angle, KAM-related variables were more positively associated with VAS pain and negatively associated with HSS score for patients with pelvic drop angle ≤3 degrees. The relationships between KAM and symptoms according to radiographic disease severity remained confusing.

Conclusions

Static alignment and pelvic drop angle significantly affected relationships between KAM-related variables and knee OA symptoms, which may explain the confusing results as shown by previous studies.

Nordic clinical guidelines for orthotic treatment of osteoarthritis of the knee: A systematic review using the AGREE II instrument

BACKGROUND

High-quality clinical practice guidelines are necessary for effective use of resources both at an individual patient- and national-level. Nordic clinical practice guidelines recommendations for orthotic treatment of knee osteoarthritis vary and little is known about their quality.

OBJECTIVES

The aim of the study was to critically evaluate the quality of clinical practice guidelines in orthotic management of knee osteoarthritis in the Nordic countries.

STUDY DESIGN

Systematic review.

METHODS

Four national clinical practice guidelines for treatment of knee osteoarthritis were assessed for methodological rigour and transparency by four independent assessors using the AGREE II instrument. Summary domain scores and inter-rater agreement (Kendall's W) were calculated.

RESULTS

Domain scores indicate that many guidelines have not sufficiently addressed stakeholder involvement (average score: 55%), applicability (20%) and editorial independence (33%) in the development process. Inter-rater agreement for assessors indicated 'good' agreement for clinical practice guidelines from Finland, Norway and Sweden (W = 0.653, p < 0.001; W = 0.512, p = 0.003 and W = 0.532, p = 0.002, respectively) and 'strong' agreement for the clinical practice guideline from Denmark (W = 0.800, p < 0.001).

CONCLUSION

Quality of clinical practice guidelines for orthotic treatment of knee osteoarthritis in the Nordic region is variable. Future guideline development should focus on improving methodology by involving relevant stakeholders (e.g. certified prosthetist/orthotists (CPOs)), specifying conflicts of interest and providing guidance for implementation.

CLINICAL RELEVANCE

The current review suggests that, for the Nordic region, there are areas of improvement which can be addressed, which ensure clinical practice guidelines are developed under stringent conditions and based on sound methods. These improvements would ensure knee osteoarthritis patients are receiving orthotic interventions based on appropriate guidance from published guidelines.

Does Gait Retraining Have the Potential to Reduce Medial Compartmental Loading in Individuals With Knee Osteoarthritis While Not Adversely Affecting the Other Lower Limb Joints? A Systematic Review

Objectives

To review the literature regarding gait retraining to reduce knee adduction moments and their effects on hip and ankle biomechanics.

Data Sources

Twelve academic databases were searched from inception to January 2019. Key words “walk*” OR “gait,” “knee” OR “adduction moment,” “osteoarthriti*” OR “arthriti*” OR “osteo arthriti*” OR “OA,” and “hip” OR “ankle” were combined with conjunction “and” in all fields.

Study Selection

Abstracts and full-text articles were assessed by 2 individuals against a predefined criterion.

Data Synthesis

Of the 11 studies, sample sizes varied from 8-40 participants. Eight different gait retraining styles were evaluated: hip internal rotation, lateral trunk lean, toe-in, toe-out, increased step width, medial thrust, contralateral pelvic drop, and medial foot weight transfer. Using the Black and Downs tool, the methodological quality of the included studies was fair to moderate ranging between 12 of 25 to 18 of 28. Trunk lean and medial thrust produced the biggest reductions in first peak knee adduction moment. Studies lacked collective sagittal and frontal plane hip and ankle joint biomechanics. Generally, studies had a low sample size of healthy participants with no osteoarthritis and assessed gait retraining during 1 laboratory visit while not documenting the difficulty of the gait retraining style.

Conclusions

Gait retraining techniques may reduce knee joint loading; however, the biomechanical effects to the pelvis, hip, and ankle is unknown, and there is a lack of understanding for the ease of application of the gait retraining styles.

Longitudinal Changes in the Total Knee Joint Moment After Anterior Cruciate Ligament Reconstruction Correlate With Cartilage Thickness Changes

This study investigated associations between changes in the total joint moment (TJM) at the knee and changes in cartilage thickness after anterior cruciate ligament reconstruction (ACLR). Seventeen subjects (five males; age: 29.6 ± 7.3 years) with unilateral ACLR underwent gait analysis and magnetic resonance imaging at baseline (2.2 ± 0.3 years post-ACLR) and at long-term follow-up (7.7 ± 0.7 years post-ACLR). Knee loading was assessed using the TJM, and differences in loading were analyzed using repeated measures analysis of variance. Pearson correlation coefficients assessed associations between changes in TJM and changes in (medial-to-lateral) M/L femoral cartilage thickness ratios in the ACLR limb. Bilaterally, there was no significant change in the magnitude of the TJM first peak (TJM1), however, there was a significant increase in the percent contribution of the knee flexion moment (KFM) (p < 0.001) and decrease in the percent contribution of the knee adduction moment (KAM) to TJM1 (p < 0.001). The change in the percent contributions of KFM and KAM to TJM1 were associated with changes in M/L femoral cartilage thickness in the ACLR limb. Specifically, subjects with smaller increases in KFM contribution (R = 0.521, p = 0.032) and smaller decreases in KAM contribution (R = -0.521, p = 0.032) had a reduction in the M/L ratio in the central femoral subregion over the follow-up period, with similar trends in the external femoral subregion. The study results provide new insight into changes in the loading environment at the knee joint prospectively following ACL reconstruction and give evidence that there are modifiable gait metrics that are associated with cartilage changes after ACLR. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1546-1554, 2019.

Unloader knee brace increases medial compartment joint space during gait in knee osteoarthritis patients

PURPOSE

The purpose of the present study was to investigate the effect of the unloader brace on medial compartment dynamic joint space (DJS) during gait, while simultaneously recording ground reaction force (GRF) in varus knee osteoarthritis (OA) patients using a highly accurate biplane radiography system which allowed continuous measurement of DJS from heel strike through the midstance phase of gait. The hypothesis was that DJS in the medial compartment would be greater with the unloader brace than without the brace during gait.

METHODS

After 2 weeks of daily use of the unloader brace, ten varus knee OA patients (age 52 ± 8 years) walked with and without the brace on an instrumented treadmill, while biplane radiographs of the OA knees were acquired at 100 Hz. Medial compartment DJS was determined from heel strike to terminal stance (0-40% of the gait cycle) using a validated volumetric model-based tracking process that matches subject-specific 3D bone models to the biplane radiographs. The GRF during gait was collected at 1000 Hz. Repeated-measures ANOVA was used to explore differences in medial compartment DJS and GRF between the unbraced and braced conditions. A patient-reported subjective questionnaire related to the brace use was collected at the time of the test.

RESULTS

Medial compartment DJS was significantly greater with the unloader brace than without the brace during gait (P = 0.005). The average difference was 0.3 mm (95% confidence interval 0.1-0.4 mm). No significant difference was observed in terms of vertical GRF between the two conditions. The questionnaire showed participants felt reduced pain when wearing the brace.

CONCLUSION

The unloader brace has the significant effect of increasing medial compartment DJS during gait, which supports the underlying premise that the unloader brace reduces pain by increasing medial joint space during dynamic loading activities.

LEVEL OF EVIDENCE

III.

Sensitivity of medial-lateral load sharing to changes in adduction moments or angles in an asymptomatic knee joint model during gait

BACKGROUND

Osteoarthritis (OA) of the knee joint is a common disease accompanied by pain and impaired mobility. Despite some recent concerns on the lack of correlation between the medial load and the knee adduction moment (KAM), KAM is routinely considered as a surrogate measure of medial load and hence a marker where its reduction is the main focus of preventive and treatment interventions.

RESEARCH QUESTION

Determine the relative sensitivity of the tibiofemoral medial-lateral contact load partitioning to changes in the knee adduction angle (KAA) versus KAM.

METHODS

Using a lower extremity hybrid musculoskeletal (MS) model driven by gait kinematics and kinetics, we compute here in asymptomatic subjects the sensitivity of the knee joint biomechanical response (muscle and ligament forces) in general and medial/lateral load partitioning in particular to the relative changes in the reported KAA versus changes in reported KAM (both by one standard deviation).

RESULTS

As KAA increased (at constant KAM), so did the passive moment resistance of the knee joint which as a result and at all stance periods substantially reduced forces in lateral hamstrings while increasing those in medial hamstrings. At 25% and 75% stance as two highly loaded periods of gait, the drop in KAA (from + SD to -SD while at constant KAM) drastically reduced the medial contact force by 44% and 30% and the medial over lateral contact load and area ratios by 92% and 79% as well as 64% and 51%, respectively. In contrast, the equivalent alterations in KAM (by ± SD at constant KAA) had lower and less consistent effects (<7%) showing much smaller sensitivity to changes in KAM alone. Ligament forces altered at various stance periods with inconsistent trends; peak values of 418 N in the anterior cruciate ligament (90% carried by the posterolateral bundle) and 1056 N in the patellar tendon were computed both at 25% stance and minimum KAA.

SIGNIFICANCE

These findings indicate a poor correlation between KAM and tibiofemoral load distribution suggesting instead that KAA and knee alignment should be in focus as the primary marker of knee joint load partitioning and associated prevention and treatment interventions.

Can the use of proprioceptive knee braces have implications in the management of osteoarthritic knees: An exploratory study

BACKGROUND:

Use of proprioceptive knee braces to control symptomology by altering neuromuscular control mechanisms has been shown in patellofemoral pain. Although their potential in patients with knee osteoarthritis is vast, little research has examined their efficacy.

OBJECTIVES:

This study examines the effect of a proprioceptive knee brace on lower limb kinematics and kinetics in healthy participants and in participants with OA.

METHODS:

Thirteen healthy participants were asked to perform a 10-cm step-down task with and without a proprioceptive brace. Data were collected using a 10-camera Qualisys system. Individuals with osteoarthritis completed the Knee injury and Osteoarthritis Outcome Score before and after 4 weeks of intervention.

RESULTS:

During step-down reductions in knee maximum internal rotation, transverse range of movement, transverse plane angular velocity and maximum internal rotation angular velocity was seen. Ankle plantar flexion and inversion angular velocity decreased while inversion and maximum supination angular velocity increased. Improvements in Knee injury and Osteoarthritis Outcome Score were noted across all parameters with brace use.

CONCLUSION:

Positive changes in kinematic variables in multiple planes can be achieved with proprioceptive bracing alongside improved patient outcome. These changes occur at the knee but analysis of other weight bearing joints should not be overlooked in future studies. This study supports the concept of neuromuscular reinforcement and re-education through proprioceptive bracing and its application in the management in knee osteoarthritis.

CLINICAL RELEVANCE

Proprioception can alter symptoms and biomechanics embraced and adjacent lower limb joints. The results of this study highlights the potential uses of non-mechanical bracing in the treatment of osteoarthritis and other potential to bridge the osteoarthritis treatment gap. Furthermore, large-scale research is needed to match disease subset to brace type.

Effects of a valgus unloader brace in the medial meniscectomized knee joint: a biomechanical study

Background

Patients undergoing total or partial arthroscopic meniscectomy for treating traumatic meniscal tears are at greater risk of developing knee osteoarthritis (OA) due to increased mechanical load. The purpose of this study was to evaluate the effects of a valgus unloader brace in the medial meniscectomized knee joint during the gait cycle.

Methods

A three-dimensional finite element model of the knee joint was developed using the substructures segmented from magnetic resonance images. Experimentally measured forces and moments for one complete gait cycle, without brace and with brace at three different alignment angles (0°, 4°, and 8°), were applied to the finite element model, and the changes in the tibiofemoral contact mechanics were estimated.

Results

The brace in 0°/4°/8° valgus alignment modes reduced the total contact force in the medial compartment by 16%/46%/82% at opposite toe off and 18%/17%/29% at opposite initial contact events, while it increased the total contact force in the lateral compartment by 31%/81%/110% at opposite toe off and 30%/38%/45% at opposite initial contact events, respectively, when compared to the unbraced meniscectomized knee.

Conclusions

Increasing the valgus alignment from 0° to 4° and 8° resulted in a greater reduction of contact conditions (total contact force, total contact area, peak contact pressure) in the medial compartment and vice versa in the lateral compartment. This decrease in contact conditions in the medial compartment infers enhanced knee joint function due to a valgus unloader brace, which translates to increased knee-related confidence. Results suggest choosing a higher valgus alignment angle could potentially increase the risk for the onset of osteoarthritis in the lateral compartment, and this computational model could be used in validating the effectiveness of braces on joint health.

Electronic supplementary material

The online version of this article (10.1186/s13018-019-1085-1) contains supplementary material, which is available to authorized users.

Immediate effects of valgus knee bracing on tibiofemoral contact forces and knee muscle forces

Background Valgus knee braces have been reported to reduce the external knee adduction moment during walking. However, mechanistic investigations into the effects of valgus bracing on medial compartment contact forces using electromyogram-driven neuromusculoskeletal models are limited. Research question What are the immediate effects of valgus bracing on medial tibiofemoral contact forces and muscular loading of the tibiofemoral joint? Methods Sixteen (9 male) healthy adults (27.7 ± 4.4 years) performed 20 over-ground walking trials at self-selected speed both with and without an Ossür Unloader One® brace. Assessment order (i.e., with or without brace) was randomised and counterbalanced to prevent order effects. While walking, three-dimensional lower-body motion, ground reaction forces, and surface electromyograms from eight lower-limb muscles were acquired. These data were used to calibrate an electromyogram-driven neuromusculoskeletal model of muscle and tibiofemoral contact forces (N), from which muscle and external load contributions (%) to those contact forces were determined. Results Although walking with the brace resulted in no significant changes in peak tibiofemoral contact forces at the group-level, individual responses were variable and non-uniform. At the group-level, wearing the brace resulted in a 2.35% (95% CI 0.46-4.24; p = 0.02) greater relative contribution of muscle to lateral compartment contact loading (54.2 ± 11.1%) compared to not wearing the brace (51.8 ± 12.1%) (p < 0.05). Average relative contributions of muscle and external loads to medial compartment loading were comparable between brace and no brace conditions (p ≥ 0.05). Significance Wearing a valgus knee brace did not immediately reduce peak tibiofemoral contact forces in healthy adults during normal walking. It appears this population may modulate muscle activation patterns to support brace-generated valgus moments, thereby maintaining normal walking knee moments and tibiofemoral contact forces. Future investigations are warranted to better understand effects of valgus knee brace in people with medial knee osteoarthritis using an electromyogram-driven neuromusculoskeletal model.

Methods for evaluating effects of unloader knee braces on joint health: a review

The paper aims to provide a state-of-the-art review of methods for evaluating the effectiveness and effect of unloader knee braces on the knee joint and discuss their limitations and future directions. Unloader braces are prescribed as a non-pharmacological conservative treatment option for patients with medial knee osteoarthritis to provide relief in terms of pain reduction, returning to regular physical activities, and enhancing the quality of life. Methods used to evaluate and monitor the effectiveness of these devices on patients' health are categorized into three broad categories (perception-, biochemical-, and morphology-based), depending upon the process and tools used. The main focus of these methods is on the short-term clinical outcome (pain or unloading efficiency). There is a significant technical, research, and clinical literature gap in understanding the short- and long-term consequences of these braces on the tissues in the knee joint, including the cartilage and ligaments. Future research directions may complement existing methods with advanced quantitative imaging (morphological, biochemical, and molecular) and numerical simulation are discussed as they offer potential in assessing long-term and post-bracing effects on the knee joint.

Acute effects of different orthotic interventions on knee loading parameters in knee osteoarthritis patients with varus malalignment

BACKGROUND

Knee osteoarthritis (KOA) is the most common form of arthritis with an estimated lifetime prevalence of 45%. The use of orthotic devices is a generally accepted conservative therapy in KOA. A new conservative treatment is an ankle-foot orthosis (AFO); however, studies on the biomechanical effects are limited. The aim of this study was to examine the acute effects of different orthotic devices (AFO, knee brace and wedged shoes) on (un)loading parameters in subjects with KOA.

METHODS

Fifty-two medial KOA patients (mean age 59 (standard deviation (SD) 10) years and mean body mass index 27.5 (SD 4.9) kg/m²) were recruited. Three-dimensional gait analysis was undertaken with different interventions in a randomized order: control (own shoes), new AFO, conventional unloader brace and laterally wedged shoes (six degrees).

RESULTS

Significant decreases of 27% and nine percent in first peak knee adduction moment (KAM) were observed for the AFO and wedged shoes, respectively, in comparison with the control. Significant decreases of 21%, seven percent and 18% in the KAM impulse were observed for the AFO, brace and wedged shoes, respectively, compared to the control. The knee flexion moment (KFM) increased compared to the control for all conditions, but only significantly while using the AFO, showing an increase of 26% as compared to the control.

CONCLUSIONS

The AFO and wedged shoes were more effective in unloading the medial compartment of the knee compared to the unloader brace. However, the effect of an increased KFM on KOA remains unclear and requires further investigation.

The immediate effect of a soft knee brace on dynamic knee instability in persons with knee osteoarthritis

Objectives

Wearing a soft knee brace has been shown to reduce self-reported knee instability in persons with knee OA. There is a need to assess whether a soft knee brace has a beneficial effect on objectively assessed dynamic knee instability as well. The aims of the study were to evaluate the effect of a soft knee brace on objectively assessed dynamic knee instability and to assess the difference in effect between a non-tight and a tight soft knee brace in persons with knee OA.

Methods

Thirty-eight persons with knee OA and self-reported knee instability participated in a laboratory study. A within-subject design was used comparing no brace vs brace and comparing a non-tight vs a tight brace. The primary outcome measure was dynamic knee instability, expressed by the perturbation response (PR). The PR reflects deviation in the mean knee varus-valgus angle during level walking after a controlled mechanical perturbation. Linear mixed-effect model analysis was used to evaluate the effect of a brace on dynamic knee instability.

Results

Wearing a brace significantly reduced the PR compared with not wearing a brace (B = -0.16, P = 0.01). There was no difference between a non-tight and a tight brace (B = -0.03, P = 0.60).

Conclusion

This study is the first to report that wearing a soft knee brace reduces objectively assessed dynamic knee instability in persons with knee OA. Wearing a soft brace results in an objective improvement of knee instability beyond subjectively reported improvement.

Trial registration

Nederlands Trial register (trialregister.nl) NTR6363.

Validation of method for analysing mechanics of unloader brace for medial knee osteoarthritis

Unloader braces are one non-invasive treatment of knee osteoarthritis, which primarily function by applying an external abduction moment to the joint to reduce loads in the medial compartment of the knee. We developed a novel method using brace deflection to estimate the mechanical effect of valgus braces and validated this model using strain gauge instrumentation. Three subjects performed static and walking trials, in which the moment applied by an instrumented brace was calculated using the deflection and strain methods. The deflection method predicted average brace moments of 8.7 Nm across static trials; mean error between the deflection model predictions and the gold-standard strain gauge measurements was 0.32 Nm. Mean brace moment predictions throughout gait ranged from 7.1 to 8.7 Nm using the deflection model. Maximum differences (MAE) over the gait cycle in mean and peak brace moments between methods were 1.50 Nm (0.96) and 0.60 Nm (0.42). Our proposed method enables quantification of brace abduction moments without the use of custom instrumentation. While the deflection-based method is similar to that implemented by Schmalz et al. (2010), the proposed method isolates abduction deflection from the 3 DOF angular changes that occur within the brace. Though the model should be viewed with more caution during swing (MAE = 1.16 Nm), it was shown that the accuracy is influenced by the uncertainty in angle measurement due to cluster spacing. In conclusion, the results demonstrate that the deflection-based method developed can predict comparable brace moments to those of the previously established strain method.

Current status and future prospects for disease modification in osteoarthritis

OA is a chronic, progressive and disabling joint disease, leading to a poor quality of life and an enormous social and economic burden. Current therapies for OA patients remain limited, which creates an area of huge unmet medical need. For some time, researchers have been looking for approaches that can inhibit the structural progression of OA. A variety of potential disease-modifying OA drugs have been developed, targeting cartilage, inflammatory pathways or subchondral bone. In addition, non-pharmacological therapies, including joint distraction and weight loss, draw increasing attention, with some showing disease-modifying potential. Thus we performed a comprehensive review to discuss the current status of disease-modifying therapies in OA and appraise the potentials of emerging novel agents.

Gait Analysis of Leg Length Discrepancy-Differentiated Hip Replacement Patients With Developmental Dysplasia: A Midterm Follow-Up

BACKGROUND

Few studies investigate gait characteristics and symmetry of developmental dysplasia of the hip patients (Crowe II and III) after total hip arthroplasty (THA) whose leg length discrepancy (LLD) is within 20 mm. Our study aimed to explore whether gait analysis parameters in these patients can return to the level of unaffected people and how bodies compensate for the discrepancy.

METHOD

A total of 45 patients who underwent cementless THA and 20 healthy controls were involved in this study prospectively. Group 1 includes patients whose LLD is <10 mm and group 2 includes patients whose LLD is 10-20 mm. Gait analysis was performed during 5-year midterm postoperative follow-up.

RESULT

The parameters, particularly the range of motion (ROM) in the hip, in both experimental groups (1 and 2) were significantly lower than healthy control group. For the nonoperated side, group 1 displayed significantly reduced ROM in the hip and knee compared with the age-matched controls. This was not observed in group 2. Greater bilateral symmetry can be seen in group 1 compared with group 2.

CONCLUSION

Despite LLD being limited to within 20 mm, THA patients in both groups showed a less efficient gait than that of healthy controls on 5-year midterm follow-up. The increased ROM in the nonoperated hip may act as a compensatory mechanism. LLD of 10 mm may be a cutoff value to assess whether compensation occurs in the contralateral limb. Reconstruction of equal limb length is recommended when surgeons perform THA for dysplastic hips.

Comparison of the effects of kilohertz- and low-frequency electric stimulations: A systematic review with meta-analysis

OBJECTIVE

This study aimed to determine whether kilohertz-frequency alternating current (KFAC) is superior to low-frequency pulsed current (PC) in increasing muscle-evoked torque and lessening discomfort.

DATA SOURCES

The electronic databases PubMed, PEDro, CINAHL, and CENTRAL were searched for related articles, published before August 2017. Furthermore, citation search was performed on the original record using Web of Science.

REVIEW METHODS

Randomized controlled trials, quasi-experimental studies, and within-subject repeated studies evaluating and comparing KFAC and PC treatments were included. The pooled standardized mean differences (SMDs) of KFAC and PC treatments, with 95% confidence intervals (CIs), were calculated using the random effects model.

RESULTS

In total, 1148 potentially relevant articles were selected, of which 14 articles with within-subject repeated designs (271 participants, mean age: 26.4 years) met the inclusion criteria. KFAC did not significantly increase muscle-evoked torque, compared to PC (pooled SMD: -0.25; 95% CI: -0.53, 0.06; P = 0.120). KFAC had comparable discomfort compared to that experienced using PC (pooled SMD: -0.06; 95% CI: -0.50, 0.38; P = 0.800). These estimates of the effects had a high risk of bias, as assessed using the Downs and Black scale, and were highly heterogeneous studies.

CONCLUSIONS

This meta-analysis does not establish that KFAC is superior to PC in increasing muscle-evoked torque and lessening discomfort level. However, no strong conclusion could be drawn because of a high risk of bias and a large amount of heterogeneity. High quality studies comparing the efficacy between PC and KFAC treatments with consideration of potential confounders is warranted to facilitate the development of effective treatment.

Comparison between in vitro and in vivo cartilage overloading studies based on a systematic literature review

Methodological differences between in vitro and in vivo studies on cartilage overloading complicate the comparison of outcomes. The rationale of the current review was to (i) identify consistencies and inconsistencies between in vitro and in vivo studies on mechanically-induced structural damage in articular cartilage, such that variables worth interesting to further explore using either one of these approaches can be identified; and (ii) suggest how the methodologies of both approaches may be adjusted to facilitate easier comparison and therewith stimulate translation of results between in vivo and in vitro studies. This study is anticipated to enhance our understanding of the development of osteoarthritis, and to reduce the number of in vivo studies. Generally, results of in vitro and in vivo studies are not contradicting. Both show subchondral bone damage and intact cartilage above a threshold value of impact energy. At lower loading rates, excessive loads may cause cartilage fissuring, decreased cell viability, collagen network de-structuring, decreased GAG content, an overall damage increase over time, and low ability to recover. This encourages further improvement of in vitro systems, to replace, reduce, and/or refine in vivo studies. However, differences in experimental set up and analyses complicate comparison of results. Ways to bridge the gap include (i) bringing in vitro set-ups closer to in vivo, for example, by aligning loading protocols and overlapping experimental timeframes; (ii) synchronizing analytical methods; and (iii) using computational models to translate conclusions from in vitro results to the in vivo environment and vice versa. © 2018 The Authors. Journal of Orthopaedic Research® Published by Wiley Periodicals, Inc. J Orthop Res 9999:1-11, 2018.

Relative and absolute test-retest reliabilities of biomechanical risk factors for knee osteoarthritis progression: benchmarks for meaningful change

OBJECTIVE

Biomechanical factors are important treatment targets in knee osteoarthritis. The knee adduction (KAM) and flexion (KFM) moments, quadriceps strength and power, load frequency, and body mass index (BMI) all have the potential to affect knee articular cartilage integrity by modulating forces across the joint. To identify clinically meaningful change, however, these measurements must be reliable and sensitive to change. This study estimated relative and absolute test-retest reliabilities over long periods of biomechanical risk factors for knee osteoarthritis progression.

METHOD

Data from a longitudinal, observational study were analyzed for knee osteoarthritis patients with data at baseline, 6-month and 24-month follow-ups. Gait kinematics and kinetics, quadriceps strength and power, daily load frequency and BMI were collected. Relative and absolute test-retest reliabilities of these measures were estimated using intraclass correlation coefficients (ICCs) and standard errors of measurement (SEMs), respectively. Minimal detectable change at the 95% confidence level (MDC95) was also calculated.

RESULTS

Data from 46 participants [36 women; age 61.0 (6.6) years] were included. Good-to-excellent relative reliabilities (ICC ≥ 0.80) indicated that KAM peak and impulse, quadriceps strength and power, and BMI had a strong ability to discriminate amongst participants. Absolute reliabilities were high for quadriceps strength and BMI, which demonstrated reasonable within-participant variability (SEMs ≤ 11% of the mean). The MDC95 values supported use of clinical interventions effective in reducing BMI and KAM, and increasing quadriceps strength.

CONCLUSION

These data are useful in interpreting findings from interventional or longitudinal investigations by determining whether observed changes are beyond measurement error and interpretable as true change.