The effectiveness of self-adjustable custom and off-the-shelf bracing in the treatment of varus gonarthrosis

Advances in active knee brace technology: A review of gait analysis, actuation, and control applications

This article discusses the significance of knee joint mechanics and the consequences of knee dysfunctions on an individual's quality of life. The utilization of active knee braces, which incorporate concepts of mechatronics systems, is investigated here as a potential treatment option. The complexity of the construction of the knee joint, which has six degrees of motion and is more prone to injury since it bears weight, is emphasized in this article. By wearing braces and using other support devices, one's knee can increase stability and mobility. In addition, the paper discusses various technologies that can be used to measure the knee adduction moment and supply spatial information on gait. Actuators for active knee braces must be compact, lightweight, and capable of producing a significant amount of torque; as a result, electric, hydraulic, and pneumatic actuators are the most common types. Creating control mechanisms, such as position control techniques and force/torque control approaches, is essential to knee exoskeleton research and development. These methods might make knee joint rehabilitation and assistive technology safer and more effective.

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.

Effect of using knee valgus brace on pain and activity level over different time intervals among patients with medial knee OA: systematic review

Background

The Knee valgus brace is one of the accepted conservative interventions for patients with medial compartment knee osteoarthritis to correct the knee varus and increase functional activity level. Nevertheless, comprehensive overview of the effects of using this brace on self-reported pain activity level over time is not available. Thus, this study aimed to systematically review the effect of using this brace on pain and activity levels in the last 20 years in patients with medial compartment knee osteoarthritis.

Methods

Five databases were searched to find articles from the year 2000 to the end of November 2020: Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE, PubMed, Web of Science, and Scopus. Two reviewers independently evaluated the available articles for eligibility and assessed quality. The risk of bias in each study was assessed by two reviewers independently according to the Strengthening the Reporting of Observational Studies in Epidemiology tool (STROBE) for the non-randomized controlled studies and the Cochrane risk-of-bias tool for the randomized controlled studies.

Results

Seven randomized controlled studies and 17 cohort studies (in total 579 participants) were included in the systematic review. Most of these studies found using a knee valgus brace effective in reducing pain and improving activity level over different time intervals. The majority of the included studies (14 studies) evaluated the impact of the brace for a considerably short-term (less than 6 months). Thus, limited evidence is available on the long-term use of the knee valgus brace and its associated complications.

Conclusion

The knee valgus brace is an effective conservative intervention to improve the quality of life and reduce pain during daily activities for some patients. However, the long term of using this brace is still not very convenient, and the patients who benefit most from using the brace should be identified with high methodological quality studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04513-0.

Clinical and cost-effectiveness of bracing in symptomatic knee osteoarthritis management: protocol for a multicentre, primary care, randomised, parallel-group, superiority trial

BACKGROUND

Brace effectiveness for knee osteoarthritis (OA) remains unclear and international guidelines offer conflicting recommendations. Our trial will determine the clinical and cost-effectiveness of adding knee bracing (matched to patients' clinical and radiographic presentation and with adherence support) to a package of advice, written information and exercise instruction delivered by physiotherapists.

METHODS AND ANALYSIS

A multicentre, pragmatic, two-parallel group, single-blind, superiority, randomised controlled trial with internal pilot and nested qualitative study. 434 eligible participants with symptomatic knee OA identified from general practice, physiotherapy referrals and self-referral will be randomised 1:1 to advice, written information and exercise instruction and knee brace versus advice, written information and exercise instruction alone. The primary analysis will be intention-to-treat comparing treatment arms on the primary outcome (Knee Osteoarthritis Outcomes Score (KOOS)-5) (composite knee score) at the primary endpoint (6 months) adjusted for prespecified covariates. Secondary analysis of KOOS subscales (pain, other symptoms, activities of daily living, function in sport and recreation, knee-related quality of life), self-reported pain, instability (buckling), treatment response, physical activity, social participation, self-efficacy and treatment acceptability will occur at 3, 6, and 12 months postrandomisation. Analysis of covariance and logistic regression will model continuous and dichotomous outcomes, respectively. Treatment effect estimates will be presented as mean differences or ORs with 95% CIs. Economic evaluation will estimate cost-effectiveness. Semistructured interviews to explore acceptability and experiences of trial interventions will be conducted with participants and physiotherapists delivering interventions.

ETHICS AND DISSEMINATION

North West Preston Research Ethics Committee, the Health Research Authority and Health and Care Research in Wales approved the study (REC Reference: 19/NW/0183; IRAS Reference: 247370). This protocol has been coproduced with stakeholders including patients and public. Findings will be disseminated to patients and a range of stakeholders.

TRIAL REGISTRATION NUMBER

ISRCTN28555470.

Can Medical Cannabis Therapies be Cost-Effective in the Non-Surgical Management of Chronic Knee Pain?

Introduction:

Chronic knee pain is a common musculoskeletal condition, which usually leads to decreased quality of life and a substantial financial burden. Various non-surgical treatments have been developed to relieve pain, restore function and delay surgical intervention. Research on the benefits of medical cannabis (MC) is emerging supporting its use for chronic pain conditions. The purpose of this study was to evaluate the cost-effectiveness of MC compared to current non-surgical therapies for chronic knee pain conditions.

Methods:

We conducted a cost-utility analysis from a Canadian, single payer perspective and compared various MC therapies (oils, soft gels and dried flowers at different daily doses) to bracing, glucosamine, pharmaceutical-grade chondroitin oral non-steroidal anti-inflammatory drugs (NSAIDs), and opioids. We estimated the quality-adjusted life years (QALYs) gained with each treatment over 1 year and calculated incremental cost-utility ratios (ICURs) using both the mean and median estimates for costs and utilities gained across the range of reported values. The final ICURs were compared to willingness-to-pay (WTP) thresholds of $66 714, $133 428 and $200 141 Canadian dollars (CAD) per QALY gained.

Results:

Regardless of the estimates used (mean or median), both MC oils and soft gels at both the minimal and maximal recommended daily doses were cost-effective compared to all current knee pain therapies at the lowest WTP threshold. Dried flowers were only cost-effective up to a certain dosage (0.75 and 1 g/day based on mean and median estimates, respectively), but all dosages were cost-effective when the WTP was increased to $133 428/QALY gained.

Conclusion:

Our study showed that MC may be a cost-effective strategy in the management of chronic knee pain; however, the evidence on the medical use of cannabis is limited and predominantly low-quality. Additional trials on MC are definitely needed, specifically in patients with chronic knee pain.

An Assessment of Randomized Controlled Trial Quality in The Journal of Bone & Joint Surgery: Update from 2001 to 2013

BACKGROUND

The quality of reporting of randomized controlled trials (RCTs) published in The Journal of Bone & Joint Surgery (JBJS) from 1988 to 2000 was previously analyzed. The purpose of this current study was to analyze the quality of reporting of RCTs published in JBJS from 2001 to 2013 to identify trends over time and potential areas of improvement for future clinical trials.

METHODS

A manual search of the JBJS database identified RCTs published between January 2001 and December 2013. Quality assessments, using the Detsky quality-of-reporting index (Detsky score), a modified Cochrane risk-of-bias tool, and abstraction of relevant data identifying predictors of quality, were conducted.

RESULTS

A total of 5,780 publications were identified in JBJS from 2001 to 2013, with 285 RCTs (4.9%), representing an increase from the prior 13-year period. The overall mean transformed Detsky score (and standard error) increased significantly (p < 0.001) from 68.1% ± 1.67% to 76.24% ± 0.72%. The percentage of multicenter RCTs decreased from 67% to 31%. The percentage of positive trials also decreased from 80% to 50.5%, as did the mean sample size (212 to 166). Regression analysis indicated that trials with an epidemiologist as the first author and nonsurgical trials were significantly associated (p = 0.001) with a higher overall trial quality score. The categories of the lowest mean methodology scores were randomization and concealment, eligibility criteria, and reasons for patient exclusion, as identified with the Detsky score, and patient and assessor blinding, as identified with the risk-of-bias assessment.

CONCLUSIONS

The quantity and quality of published RCTs in JBJS have increased in the 2001 to 2013 time period compared with the previous time period. Although these improvements are encouraging, trends to smaller, single-center trials were also observed. To efficiently determine the efficacy of orthopaedic treatments and limit bias, high-quality randomized trials of appropriate sample size and rigorous design are needed.

Three-month efficacy of three knee braces in the treatment of medial knee osteoarthritis in a randomized crossover trial

Immediate biomechanical and functional effects of knee braces are often reported, however, the duration and type of knee brace treatment for knee osteoarthritis (KOA) remain unclear. The objective was to evaluate usage, comfort, pain, and knee adduction moment (KAM) of three knee braces each worn 3 months by patients. Twenty-four patients with KOA were assigned in a randomized crossover trial a valgus three-point bending system brace (V3P-brace), an unloader brace with valgus and external rotation functions (VER-brace) and a stabilizing brace used after ligament injuries (ACL-brace). Functional questionnaires and gait assessment were carried out before and after each brace wear period of 3 months. A Friedman test was applied between brace wear diary recordings. Repeated measures analyses of variance contrasted the factors brace type (ACL, V3P, and VER), time (pre and post) and wear (without and with) on comfort, pain, function, and KAM. Brace usage was similar, but the V3P-brace was slightly less worn. Discomfort was significantly lowered with the VER-brace. All knee braces relieved pain and symptoms from 10% to 40%. KAM angular impulse was reduced with the three braces, but the VER-brace obtained the lowest relative reduction of 9%. The interaction between time and wear indicated that part of the KAM reduction with brace wear was maintained post treatment. All three knee braces have great benefits for pain and function among the medial KOA population. The VER-brace offers additional advantages on daily use, comfort and KAM, which could improve compliance to brace treatment.

Pathogenesis and clinical management of obesity-related knee osteoarthritis: Impact of mechanical loading

Obesity-related osteoarthritis (OA) is a complex, multifactorial condition that can cause significant impact on patients' quality of life. Whilst chronic inflammation, adipocytokines and metabolic factors are considered to be important pathogenic factors in obesity related OA, there has been limited investigation into the biomechanical impact of obesity on OA development. This review aims to demonstrate that mechanical factors are the major pathological cause of obesity-related OA. The effect of obesity on pathological changes to the osteochondral unit and surrounding connective tissues in OA is summarized, as well as the impact of obesity-related excessive and abnormal joint loading, concomitant joint malalignment and muscle weakness. An integrated therapeutic strategy based on this multi-factorial presentation is presented, to assist in the management of obesity related OA.

THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE

Despite the high prevalence of obesity-related OA, there is no specific guideline available for obesity-related OA management. In this review, we demonstrated the pathological changes of obesity-related OA and summarized the impact of biomechanical factors by proposing a hypothetical model of obesity-related OA change. Therapeutic strategies based on adjusting abnormal mechanical effects are presented to assist in the management of obesity-related OA.

Temporary postoperative treatment with compartment-unloading knee braces or wedge insoles does not improve clinical outcome after partial meniscectomy

PURPOSE

To investigate whether temporary postoperative compartment-unloading therapy after arthroscopic partial meniscectomy (APM)-with either knee braces or wedge insoles-leads to superior clinical outcome as compared to controls. This difference in clinical outcome was tested in the form of two knee scores, physical activity and general health outcome over the first postoperative year.

METHODS

Sixty-three patients who underwent arthroscopic partial meniscectomy (APM) were randomized to one of the following three groups: 12 weeks postoperative knee compartment-unloading therapy with either a knee brace (brace group) or wedge insoles (insole group) or no specific postoperative therapy (control group). Patient-reported outcome was assessed with the International Knee Documentation Committee Subjective Knee Evaluation Form (IKDC Score), the Knee Injury and Osteoarthritis Outcome Score (KOOS), the MARX score (physical activity) and the SF-12 (general health).

RESULTS

Sixty-three patients were available for analysis. Except for the SF-12 mental score, all other scores showed significant improvement over time. With regard to the hypotheses proposed, no significant group * time interactions were observed for any of the outcome parameters. This means that the group (i.e. the type of postoperative treatment) was not related to the degree of improvement of any of the scores.

CONCLUSIONS

It was concluded that 12 weeks of compartment-unloading therapy-with either a knee brace or wedge insoles-is ineffective with regard to clinical outcome after APM. This applies to the knee score outcome, physical activity and general health outcome over the first year following APM.

LEVEL OF EVIDENCE

Randomized controlled trial, Level I.

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.

Effect of unloading brace treatment on pain and function in patients with symptomatic knee osteoarthritis: the ROTOR randomized clinical trial

Evidence is still inconclusive for the benefits of bracing in patients with knee osteoarthritis. To assess the effect of REBEL RELIEVER unloading knee brace in conservative treatment of knee osteoarthritis, a randomized controlled trial was conducted in 67 patients with symptomatic medial knee osteoarthritis, who randomly received 6-week treatment with either REBEL RELIVER unloading knee brace + usual care (Brace group, N = 32) or usual care alone (Control group, N = 35). Primary outcome was the global last 24h-pain relief (100-mm visual analogic scale [VAS]) at 6 weeks. Secondary endpoints included pain on motion (100-mm VAS), function (Lequesne index), safety and observance. At 6 weeks, mean [SD] last 24h-pain decreased significantly more in Brace group versus Control group (-41.35 [3.37] vs -15.37 [3.23], difference -25.98, 95% CI -41.64 to -10.33, P < 0.0001). Higher mean [SD] pain on motion decrease (-51.91 [3.49] vs -19.91 [3.34], difference -32.01, 95% CI -48.21 to -15.80, P < 0.0001) and better improvement of Lequesne index score (-5.8 [0.5] vs -2.3 [0.5], difference -3.5, 95% CI -5.0 to -2.0, P < 0.0001) were observed in Brace group. Safety and observance to the brace were excellent. The additive clinical benefit of wearing REBEL RELIEVER unloading knee brace was demonstrated in knee osteoarthritis patients.

Effectiveness of Valgus Offloading Knee Braces in the Treatment of Medial Compartment Knee Osteoarthritis: A Systematic Review

CONTEXT:

Knee osteoarthritis affects 9.3 million adults over age 45 years in the United States. There is significant disability associated with this condition. Given the potential complications and the significant cost to the health care system with the dramatic increase in total knee arthroplasties performed for this condition, assessment of the efficacy of nonoperative modalities, such as offloading knee braces, is essential as part of optimizing nonoperative treatment for this condition.

OBJECTIVE:

To determine the effectiveness of valgus offloader braces in improving clinical outcomes for patients with medial compartment knee osteoarthritis.

DATA SOURCES:

Three databases (PubMed, MEDLINE, and EMBASE) were searched from database inception through July 28, 2017.

STUDY SELECTION:

Studies reporting outcomes of valgus offloader knee braces in the treatment of medial compartment knee osteoarthritis were included.

STUDY DESIGN:

Systematic review.

LEVEL OF EVIDENCE:

Level 4.

DATA EXTRACTION:

Data pertaining to demographics, descriptive statistics, and clinical outcomes were extracted from the included studies. The methodological quality of included studies was evaluated.

RESULTS:

A total of 31 studies were included, with a total of 619 patients. The majority of studies reported improved pain outcomes using valgus offloader braces. However, variable results were reported as to whether valgus offloader braces significantly improved functional outcomes and stiffness. Offloader bracing was more effective at reducing pain when compared with neutral braces or neoprene sleeves.

CONCLUSION:

Valgus offloader bracing is an effective treatment for improving pain secondary to medial compartment knee osteoarthritis. The literature remains unclear on the effectiveness of valgus offloader braces with regard to functional outcomes and stiffness. Larger prospective randomized trials with consistent outcome assessment tools and consideration of patient compliance would be beneficial to more accurately determine treatment effects of valgus offloader bracing.

Gait strategies to reduce the dynamic joint load in the lower limbs during a loading response in young healthy adults

Reducing external joint moments during gait can lead to a reduction in dynamic joint load. There has yet to be a detailed investigation of gait strategies that can reduce external joint moments by decreasing the magnitude of ground reaction force (GRF) without reducing the walking speed. The objectives of this study were to verify whether it is possible to reduce external joint moments by decreasing the GRF magnitude without reducing the walking speed and to identify the alternative walking strategy involved in young healthy adults. This study included 14 young healthy subjects. They performed two types of walking: normal and impact reduction walking. For impact reduction walking, the subjects walked in a manner that reduced the impact upon foot contact. Cadence and step length were unified between the two conditions. The walking speed, peak value of vertical GRF, braking-accelerating force, loading rate, joint angle, and external joint moments of the two conditions were recorded and compared. No significant difference was noted in the walking speed. However, the first peak of vertical GRF, braking force, and loading rate during loading response were significantly reduced during impact reduction walking, and external joint moments in the hip, knee, and ankle joints were reduced. In contrast, the second peak of vertical GRF, hip extension angle, and external ankle dorsiflexion moment were significantly increased during terminal stance. Our data imply that the ankle joint function during the terminal stance is important in reducing the dynamic joint load in the contralateral leg during the loading response.

Measurements agreement between low-cost and high-level handheld 3D scanners to scan the knee for designing a 3D printed knee brace

Use of additive manufacturing is growing rapidly in the orthotics field. This technology allows orthotics to be designed directly on digital scans of limbs. However, little information is available about scanners and 3D scans. The aim of this study is to look at the agreement between manual measurements, high-level and low-cost handheld 3D scanners. We took two manual measurements and three 3D scans with each scanner from 14 lower limbs. The lower limbs were divided into 17 sections of 30mm each from 180mm above the mid-patella to 300mm below. Time to record and to process the three 3D scans for scanners methods were compared with Student t-test while Bland-Altman plots were used to study agreement between circumferences of each section from the three methods. The record time was 97s shorter with high-level scanner than with the low-cost (p = .02) while the process time was nine times quicker with the low-cost scanner (p < .01). An overestimation of 2.5mm was found in high-level scanner compared to manual measurement, but with a better repeatability between measurements. The low-cost scanner tended to overestimate the circumferences from 0.1% to 1.5%, overestimation being greater for smaller circumferences. In conclusion, 3D scanners provide more information about the shape of the lower limb, but the reliability depends on the 3D scanner and the size of the scanned segment. Low-cost scanners could be useful for clinicians because of the simple and fast process, but attention should be focused on accuracy, which depends on the scanned body segment.

Biomechanical effect of unloader braces for medial osteoarthritis of the knee: a systematic review (CRD 42015026136)

PURPOSE

There is a lack of consensus regarding biomechanical effects of unloader braces for the treatment of medial osteoarthritis (OA) of the knee. The purpose of this study was to perform a systematic review of studies examining the biomechanical effect of unloader braces.

METHODS

A systematic search for articles about the biomechanical effect of unloader braces was performed. Primary outcome measure was the influence of the brace on the knee adduction moment. Data sources were Pubmed central and google scholar.

RESULTS

Twenty-four articles were included. Twenty articles showed that valgus unloader braces significantly decrease the knee adduction moment. Seven of those studies reported a decrease of pain in braced patients (secondary outcome measure). Positive effects on the knee adduction moment could be found for custom made braces for conventional knee braces and for a foot ankle orthosis. Four studies could not show any effect of knee unloader braces on the knee adduction moment although one of these studies found decreased pain in braced patients. One of these studies examined healthy patients with a neutral axis.

CONCLUSION

This systematic review could demonstrate evidence that unloader braces reduce the adduction moment of the knee. Foresighted, a systematic review about the clinical effect of unloader braces is required.

Current state of unloading braces for knee osteoarthritis

PURPOSE

Unicompartmental knee osteoarthritis (OA) is often treated with the prescription of an unloading knee brace to decrease pain and stiffness. Braces have been shown to improve the quality of life by applying an external moment to offset increased compressive tibiofemoral contact loads, but evidence regarding mechanical efficacy at the joint is controversial. Thus, the purpose of this study was to review the current state of unloading braces on knee mechanics, clinical impact, and long-term disease progression.

METHODS

A literature search was performed through the PubMed MEDLINE database for the search terms "osteoarthritis," "knee," "brace," and derivatives of the keyword "unload." Articles published since January 1, 1980 were reviewed for their relevance. Evidence for the effectiveness of unloading braces for disease management both biomechanically and clinically was considered.

RESULTS

While significant research has been done to show improvement in OA symptoms with the use of an unloading brace, current literature suggests a debate regarding the effectiveness of these braces for biomechanical change. Clinical findings reveal overall improvements in parameters such as pain, instability, and quality of life.

CONCLUSION

Although clinical evidence supports brace use to improve pain and functional ability, current biomechanical evidence suggests that unloading of the affected knee compartment does not significantly hinder disease progression.

LEVEL OF EVIDENCE

III.

Knee joint contact mechanics during downhill gait and its relationship with varus/valgus motion and muscle strength in patients with knee osteoarthritis

OBJECTIVE

The objective of this exploratory study was to evaluate tibiofemoral joint contact point excursions and velocities during downhill gait and assess the relationship between tibiofemoral joint contact mechanics with frontal-plane knee joint motion and lower extremity muscle weakness in patients with knee osteoarthritis (OA).

METHODS

Dynamic stereo X-ray was used to quantify tibiofemoral joint contact mechanics and frontal-plane motion during the loading response phase of downhill gait in 11 patients with knee OA and 11 control volunteers. Quantitative testing of the quadriceps and the hip abductor muscles was also performed.

RESULTS

Patients with knee OA demonstrated larger medial/lateral joint contact point excursions (p < 0.02) and greater heel-strike joint contact point velocities (p < 0.05) for the medial and lateral compartments compared to the control group. The peak medial/lateral joint contact point velocity of the medial compartment was also greater for patients with knee OA compared to their control counterparts (p = 0.02). Additionally, patients with knee OA demonstrated significantly increased frontal-plane varus motion excursions (p < 0.01) and greater quadriceps and hip abductor muscle weakness (p = 0.03). In general, increased joint contact point excursions and velocities in patients with knee OA were linearly associated with greater frontal-plane varus motion excursions (p < 0.04) but not with quadriceps or hip abductor strength.

CONCLUSION

Altered contact mechanics in patients with knee OA may be related to compromised frontal-plane joint stability but not with deficits in muscle strength.

The role of knee joint moments and knee impairments on self-reported knee pain during gait in patients with knee osteoarthritis

BACKGROUND

The association between high mechanical knee joint loading during gait with onset and progression of knee osteoarthritis has been extensively studied. However, less attention has been given to risk factors related to increased pain during gait. The purpose of this study was to evaluate knee joint moments and clinical characteristics that may be associated with gait-related knee pain in patients with knee osteoarthritis.

METHODS

Sixty-seven participants with knee osteoarthritis were stratified into three groups of no pain (n=18), mild pain (n=27), or moderate/severe pain (n=22) based on their self-reported symptoms during gait. All participants underwent three-dimensional gait analysis. Quadriceps strength, knee extension range of motion, radiographic knee alignment and self-reported measures of global pain and function were also quantified.

FINDINGS

The moderate/severe pain group demonstrated worse global pain (P<0.01) and physical function scores (P<0.01) compared to the no pain and the mild pain groups. The moderate/severe pain group also walked with greater knee flexion moments during the midstance phase of gait compared to the no pain group (P=0.02). Additionally, the moderate/severe pain group demonstrated greater varus knee malalignment (P=0.009), which was associated with higher weight acceptance peak knee adduction moments (P=0.003) and worse global pain (P=0.003) and physical function scores (P=0.006).

INTERPRETATION

Greater knee flexion moment is present during the midstance phase of gait in patients with knee osteoarthritis and moderate/severe pain during gait. Additionally, greater varus malalignment may be a sign of increased global knee joint dysfunction that can influence many activities of daily living beyond gait.

Effects of a novel foot-ankle orthosis in the non-operative treatment of unicompartmental knee osteoarthritis

INTRODUCTION

Unloader braces are non-surgical treatment options for patients with unicompartmental knee osteoarthritis (OA). However, many patients do not adhere to brace treatment because of complications related to discomfort and poor fit. An alternative to knee bracing is an ankle-foot orthosis (AFO) with a lever arm that presses the lower leg into valgus or varus. The aim of this study is to evaluate the clinical benefits of this AFO for patients with unicompartmental knee OA.

MATERIALS AND METHODS

Twenty-three patients with knee OA were enrolled in this observational study. The primary clinical outcome measure was the Western Ontario and McMasters Universities Arthritis Index (WOMAC) total score. Secondary outcome measures included WOMAC subscores, visual analogue pain scale, activity restriction and complication rate. Clinical scores were collected at start and 3, 6, 9, and 12 months after enrollment. Statistical evaluation was performed using the Student's t test.

RESULTS

Of the patients enrolled, 83 % suffered from medial compartment OA. Most patients had Grade II OA according to the Kellgren and Lawrence classification. WOMAC total score, both subscores and visual analogue pain scale were significantly improved over time. Patients also noted a reduction in restrictions to activities of daily living and sport-related activities while using the AFO. No patients discontinued orthosis use because of adverse effects. Two types of complications were noted: discomfort or light pressure sores around the ankle (7 patients), and wear and tear of the shoe in which the AFO was worn (14 patients).

CONCLUSIONS

This observational study suggests that this AFO is effective at significantly reducing pain and stiffness as well as improving the physical function of patients with mild to moderate unicompartmental osteoarthritis of the knee.

Valgus bracing for knee osteoarthritis: a meta-analysis of randomized trials

OBJECTIVE

To evaluate the effects of valgus knee bracing on pain and function, and compliance and complications, in patients with medial knee osteoarthritis (OA).

METHODS

A meta-analysis of randomized controlled trials that compared changes in patient-reported pain and/or function in patients with medial knee OA was performed. Seven databases were searched from their inception to January 2014. Two reviewers independently determined study eligibility, rated risk of bias, and extracted data. Pooled estimates and 95% confidence intervals (95% CIs) for standardized mean differences (SMDs) for the improvement in pain (and function) were calculated. Event rates (proportions) were calculated for studies that reported complications.

RESULTS

Six studies were included in the meta-analysis. Overall, there was a statistically significant difference favoring the valgus brace group for improvement in pain (SMD 0.33 [95% CI 0.13, 0.52], P = 0.001) and function (SMD 0.22 [95% CI 0.02, 0.41], P = 0.03). When compared to a control group that did not use an orthosis, the effect size was moderate for pain (SMD 0.56 [95% CI 0.03, 1.09], P = 0.04) and function (SMD 0.48 [95% CI 0.02, 0.95], P = 0.04). When compared to a control group that used a control orthosis, only a small, statistically significant effect for pain remained (SMD 0.33 [95% CI 0.08, 0.58], P = 0.01). Instructions for brace use varied considerably and compliance ranged from 45% to 100%. Up to 25% of patients reported minor complications with brace use.

CONCLUSION

Meta-analysis of randomized trials suggests valgus bracing for medial knee OA results in small-to-moderate improvements in pain. Effect sizes vary based on study design and warrant future research.

Strength and Functional Improvement Using Pneumatic Brace with Extension Assist for End-Stage Knee Osteoarthritis: A Prospective, Randomized trial

Pneumatic unloader bracing with extension assists have been proposed as a non-operative modality that may delay the need for knee surgery by reducing pain and improving function. This prospective, randomized trial evaluated 52 patients who had knee osteoarthritis for changes in: (1) muscle strength; (2) objective functional improvements; (3); subjective functional improvements; (4) pain; (5) quality of life; and (6) conversion to total knee arthroplasty (TKA) compared to standard of care. Patient outcomes were evaluated at a minimum 3 months. Braced patient's demonstrated significant improvements in muscle strength, several functional tests, and patient reported outcomes when compared to the matched cohort. These results are encouraging and suggest that this device may represent a promising alternative to standard treatment methods for knee osteoarthritis.

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

To review and synthesize the biomechanical effects of valgus knee bracing for patients with medial knee osteoarthritis (OA). Electronic databases were searched from their inception to May 2014. Two reviewers independently determined study eligibility, rated study quality and extracted data. Where possible, data were combined into meta-analyses and pooled estimates with 95% confidence intervals (CI) for standardized mean differences (SMD) were calculated. Thirty studies were included with 478 subjects tested while using a valgus knee brace. Various biomechanical methods suggested valgus braces can decrease direct measures of medial knee compressive force, indirect measures representing the mediolateral distribution of load across the knee, quadriceps/hamstring and quadriceps/gastrocnemius co-contraction ratios, and increase medial joint space during gait. Meta-analysis from 17 studies suggested a statistically significant decrease in the external knee adduction moment (KAM) during walking, with a moderate-to-high effect size (SMD = 0.61; 95% CI: 0.39, 0.83; P < 0.001). Meta-regression identified a near-significant association for the KAM effect size and duration of brace use only (β, -0.01; 95% CI: -0.03, 0.0001; P = 0.06); with longer durations of brace use associated with smaller treatment effects. Minor complications were commonly reported during brace use and included slipping, discomfort and poor fit, blisters and skin irritation. Systematic review and meta-analysis suggests valgus knee braces can alter knee joint loads through a combination of mechanisms, with moderate-to-high effect sizes in biomechanical outcomes.

Immediate effects of an elastic knee sleeve on frontal plane gait biomechanics in knee osteoarthritis

INTRODUCTION

Osteoarthritis of the knee affects millions of people. Elastic knee sleeves aim at relieving symptoms. While symptomatic improvements have been demonstrated as a consequence of elastic knee sleeves, evidence for biomechanical alterations only exists for the sagittal plane. We therefore asked what effect an elastic knee sleeve would have on frontal plane gait biomechanics.

METHODS

18 subjects (8 women, 10 men) with osteoarthritis of the medial tibiofemoral joint walked over ground with and without an elastic knee sleeve. Kinematics and forces were recorded and joint moments were calculated using an inverse dynamics approach. Conditions with sleeve and without sleeve were compared with paired t-Tests.

RESULTS

With the sleeve, knee adduction angle at ground contact was reduced by 1.9 ± 2.1° (P = 0.006). Peak knee adduction was reduced by 1.5 ± 1.6° (P = 0.004). The first peak knee adduction moment and positive knee adduction impulse were decreased by 10.1% (0.74 ± 0.9 Nm • kg-1; P = 0.002) and 12.9% (0.28 ± 0.3 Nm • s • kg-1; P < 0.004), respectively.

CONCLUSION

Our study provides evidence that wearing an elastic knee sleeve during walking can reduce knee adduction angles, moments and impulse in subjects with knee osteoarthritis. As a higher knee adduction moment has previously been identified as a risk factor for disease progression in patients with medial knee osteoarthritis, we speculate that wearing a knee sleeve may be beneficial for this specific subgroup.

Device-length changes and implant function following surgical implantation of the KineSpring in cadaver knees

Introduction

The KineSpring implant system has been shown to provide load reductions at the medial compartment of the knee, and has demonstrated clinical success in reducing pain and increasing function in patients with medial knee osteoarthritis. These results depend on the ability of the KineSpring to rotate, lengthen, and shorten to accommodate knee motions, and in response to knee position and loading.

Purpose

The present study was undertaken to determine length changes of the implanted KineSpring in response to a range of knee positions, external knee loads, and placements by different orthopedic surgeons.

Materials and methods

KineSpring system components were implanted in ten cadaver leg specimens by ten orthopedic surgeons, and absorber-length changes were measured under combined loading and in different positions of the knee.

Results and conclusion

Spring compression consistent with knee-load reduction, and device lengthening and shortening to accommodate knee loads and motions were seen. These confirm the functionality of the KineSpring when implanted medially to the knee.

Do laterally wedged insoles or valgus braces unload the medial compartment of the knee in patients with osteoarthritis?

BACKGROUND

The results of conservative treatment of knee osteoarthritis (OA) are generally evaluated in epidemiological studies with clinical outcome measures as primary outcomes. Biomechanical evaluation of orthoses shows that there are potentially beneficial biomechanical changes to joint loading; however, evaluation in relation to clinical outcome measures in longitudinal studies is needed.

QUESTIONS/PURPOSES

We asked (1) is there an immediate effect on gait in patients using a laterally wedged insole or valgus knee brace; (2) is there a late (6 weeks) effect; and (3) is there a difference between subgroups within each group with respect to patient compliance, body mass index, and OA status?

METHODS

This was a secondary analysis of data from a previous randomized controlled trial of patients with early medial knee OA. A total of 91 patients were enrolled in that trial, and 73 (80%) completed it after 6 months. Of the enrolled patients, 80 (88%) met prespecified inclusion criteria for analysis in the present study. The patients were randomized to an insole or brace. Gait was analyzed with and without wearing the orthosis (insole or brace) at baseline and after 6 weeks. Measurements were taken of the knee adduction moment, ground reaction force, moment arm, walking speed, and toe-out angle. Data were analyzed with regression analyses based on an intention-to-treat principle.

RESULTS

A mean reduction of 4% (±10) (95% confidence interval [CI], -0.147 to -0.03, p=0.003) of the peak knee adduction moment and 4% (±13) (95% CI, -0.009 to -0.001, p=0.01) of the moment arm at baseline was observed in the insole group when walking with an insole was compared with walking without an insole. A mean reduction of 1% (±10) (95% CI, -0.002 to -0.001, p=0.001) of the peak knee adduction moment and no reduction of the moment arm were measured after 6 weeks. No reduction of knee adduction moment, moment arm, or ground reaction force was seen in the brace group at baseline and after 6 weeks. Subgroup analysis showed no differences in biomechanical effect for obesity, stage of OA, and whether patients showed a clinical response to the treatment.

CONCLUSIONS

Laterally wedged insoles unload the medial compartment only at baseline in patients with varus alignment and by an amount that might not be clinically important. No biomechanical alteration was seen after 6 weeks of wearing the insole. Valgus brace therapy did not result in any biomechanical alteration. Taken together, this study does not show a clinically relevant biomechanical effect of insole and brace therapy in patients with varus medial knee OA.

LEVEL OF EVIDENCE

Level I, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

[Sense or nonsense of unloader braces]

BACKGROUND

Unloader knee braces are a viable and cost-effective alternative in for treatment of medial osteoarthritis of the knee in selected patients. They provide the potential to predict which patients could benefit from a high tibial osteotomy (HTO) and which patients should better be treated which a unicondylar or bicondylar knee replacement.

DISCUSSION

A direct clinical benefit in pain reduction as well as improved knee function has been shown in several clinical studies; however, the underlying mechanism remains uncertain. A potential reduction of the load in the medial compartment of the knee joint by reducing the varus or valgus deformity as well as a reduction of enhanced muscle contraction is discussed.

CONCLUSION

Despite the promising short-term results, possible long-term benefits of unloader braces are controversial. As possible reasons, natural progression of the underlying osteoarthritis as well as compliance of the patients to wear the braces diminishes significantly with time.

Biomechanical effectiveness of a distraction-rotation knee brace in medial knee osteoarthritis: preliminary results

BACKGROUND

Non-pharmacological therapies are recommended for the care of knee osteoarthritis patients. Unloader knee braces provide an interesting functional approach, which aims to modulate mechanical stress on the symptomatic joint compartment. We aimed to confirm the biomechanical effects and evaluate functional benefits of a new knee brace that combines a valgus effect with knee and tibial external rotation during gait in medial osteoarthritis patients.

METHODS

Twenty patients with unilateral symptomatic medial knee osteoarthritis were included and they performed two test sessions of 3D gait analysis with and without the brace at the initial evaluation (W0) and after 5weeks (W5) of wearing the brace. VAS-pain, satisfaction scores, WOMAC scores, spatio-temporal gait parameters (gait speed, stride length, stance and double stance phases, step width), and biomechanical data of the ipsilateral lower limb (hip, knee, ankle and foot progression angles) were recorded at each session.

RESULTS

VAS-pain and WOMAC significantly decreased at W5. Walking speed was not significantly modified by knee bracing at W0, but increased significantly at W5. Knee adduction moments and foot progression angles significantly decreased in the terminal stance and push off, respectively, with bracing at W0 and W5. Lower-limb joint angles, moments and powers were significantly modified by wearing the brace at W0 and W5.

CONCLUSION

This new knee brace with distraction-rotation effects significantly alters knee adduction moments and foot progression angles during gait, which might lead to significant functional gait improvements and have carry-over effects on pain at the short term in osteoarthritis patients (<2 months).

LEVEL OF EVIDENCE

level IV.

Does an unloader brace reduce knee loading in normally aligned knees?

BACKGROUND

Unloading knee braces often are used after tibiofemoral articular cartilage repair. However, the experimental basis for their use in patients with normal tibiofemoral alignment such as those undergoing cartilage repair is lacking.

QUESTIONS/PURPOSES

The purpose of this study was to investigate the effect of varus and valgus adjustments to one commercially available unloader knee brace on tibiofemoral joint loading and knee muscle activation in populations with normal knee alignment.

METHODS

The gait of 20 healthy participants (mean age 28.3 years; body mass index 22.9 kg/m(2)) was analyzed with varus and valgus knee brace conditions and without a brace. Spatiotemporal variables were calculated as were knee adduction moments and muscle activation during stance. A directed cocontraction ratio was also calculated to investigate the relative change in the activation of muscles with medial (versus lateral) moment arms about the knee. Group differences were investigated using analysis of variance. The numbers available would have provided 85% power to detect a 0.05 increase or decrease in the knee adduction moment (Nm/kg*m) in the braced condition compared with the no brace condition.

RESULTS

With the numbers available, there were no differences between the braced and nonbraced conditions in kinetic or muscle activity parameters. Both varus (directed cocontraction ratio 0.29, SD 0.21, effect size 0.95, p = 0.315) and valgus (directed cocontraction ratio 0.28, SD 0.24, effect size 0.93, p = 0.315) bracing conditions increased the relative activation of muscles with lateral moment arms compared with no brace (directed cocontraction ratio 0.49, SD 0.21).

CONCLUSIONS

Results revealed inconsistencies in knee kinetics and muscle activation strategies after varus and valgus bracing conditions. Although in this pilot study the results were not statistically significant, the magnitudes of the observed effect sizes were moderate to large and represent suitable pilot data for future work. Varus bracing increased knee adduction moments as expected; however, they produced a more laterally directed muscular activation profile. Valgus bracing produced a more laterally directed muscular activation profile; however, it increased knee adduction moments.

CLINICAL RELEVANCE

When evaluating changes in knee kinetics and muscle activation together, this study demonstrated conflicting outcomes and questions the efficacy for the use of unloader bracing for people with normally aligned knees such as those after articular cartilage repair.

Clinical rehabilitation guidelines for matrix-induced autologous chondrocyte implantation on the tibiofemoral joint

Autologous chondrocyte implantation (ACI) has become an established technique for the repair of full-thickness chondral defects in the knee. Matrix-induced ACI (MACI) is the third and current generation of this surgical technique, and, while postoperative rehabilitation following MACI aims to restore normal function in each patient as quickly as possible by facilitating a healing response without overloading the repair site, current published guidelines appear conservative, varied, potentially outdated, and often based on earlier ACI surgical techniques. This article reviews the existing evidence-based literature pertaining to cell loading and postoperative rehabilitation following generations of ACI. Based on this information, in combination with the technical benefits provided by third-generation MACI in comparison to its surgical predecessors, we present a rehabilitation protocol for patients undergoing MACI in the tibiofemoral joint that has now been implemented for several years by our institution in patients with MACI, with good clinical outcomes.

Nonoperative treatment approach to knee osteoarthritis in the master athlete

Context:

Middle-age and elderly participants in athletic activities frequently encounter the chronic disabling process of osteoarthritis. Knowledge of the treatment of knee osteoarthritis is needed to keep the master athlete active.

Objective:

This article reviews the current scientific evidence regarding recommendations for the maturing athlete, specifically discussing the strengths and weaknesses of dietary and lifestyle modifications, physical therapy, bracing, supplements, pharmacotherapies, and biologics in the management of knee osteoarthritis.

Level of Evidence:

Level 4.

Conclusion:

These treatment modalities can help keep the aging athlete active, which in itself plays an important role in reducing the symptoms of knee osteoarthritis.

Is valgus unloader bracing effective in normally aligned individuals: implications for post-surgical protocols following cartilage restoration procedures

PURPOSE

Utilizing valgus unloader braces to reduce medial compartment loading in patients undergoing cartilage restoration procedures may be an alternative to non-weightbearing post-operative protocols in these patients. It was hypothesized that valgus unloader braces will reduce knee adduction moment during the stance phase in healthy subjects with normal knee alignment.

METHODS

Gait analysis was performed on twelve adult subjects with normal knee alignment and no history of knee pathology. Subjects were fitted with an off-the-shelf adjustable valgus unloader brace and tested under five conditions: one with no brace and four with increasing valgus force applied by the brace. Frontal and sagittal plane knee angles and external moments were calculated during stance via inverse dynamics. Analyses of variance were used to assess the effect of the brace conditions on frontal and sagittal plane joint angles and moments.

RESULTS

With increasing tension in the brace, peak frontal plane knee angle during stance shifted from 1.6° ± 4.2° varus without the brace to 4.1° ± 3.6° valgus with maximum brace tension (P = 0.02 compared with the no brace condition). Peak knee adduction moment and knee adduction impulse decreased with increasing brace tension (main effect of brace, P < 0.001). Gait velocity and sagittal plane knee biomechanics were minimally affected.

CONCLUSION

The use of these braces following a cartilage restoration procedure may provide adequate protection of the repair site without limiting the patient's mobility.

A biomechanical perspective on physical therapy management of knee osteoarthritis

SYNOPSIS

Altered knee joint biomechanics and excessive joint loading have long been considered as important contributors to the development and progression of knee osteoarthritis. Therefore, a better understanding of how various treatment options influence the loading environment of the knee joint could have practical implications for devising more effective physical therapy management strategies. The aim of this clinical commentary was to review the pertinent biomechanical evidence supporting the use of treatment options intended to provide protection against excessive joint loading while offering symptomatic relief and functional improvements for better long-term management of patients with knee osteoarthritis. The biomechanical and clinical evidence regarding the effectiveness of knee joint offloading strategies, including contralateral cane use, laterally wedged shoe insoles, variable-stiffness shoes, valgus knee bracing, and gait-modification strategies, within the context of effective disease management is discussed. In addition, the potential role of therapeutic exercise and neuromuscular training to improve the mechanical environment of the knee joint is considered. Management strategies for treatment of joint instability and patellofemoral compartment disease are also mentioned. Based on the evidence presented as part of this clinical commentary, it is argued that special considerations for the role of knee joint biomechanics and excessive joint loading are necessary in designing effective short- and long-term management strategies for treatment of patients with knee osteoarthritis.

LEVEL OF EVIDENCE

Therapy, level 5.

Effects of a modified shoe on knee load in people with and those without knee osteoarthritis

OBJECTIVE

To evaluate the effects of a modified shoe that incorporates both lateral wedging and a variable-stiffness sole on knee joint loading in 3 populations: individuals with symptomatic and radiographic knee osteoarthritis (OA), asymptomatic overweight individuals, and asymptomatic healthy weight individuals.

METHODS

Ninety participants (30 per group) underwent a 3-dimensional gait analysis across 3 test conditions: modified shoes, standard control shoes, and barefoot. For each condition, the first peak knee adduction moment (KAM) and knee flexion moment (KFM) (both expressed as Nm/[body weight × height]%) as well as the KAM impulse (expressed as Nm.s/[body weight × height]%) were determined.

RESULTS

The modified shoes significantly reduced the peak KAM as compared to the control shoes in both the OA (P = 0.002) and the overweight (P = 0.03) groups. In the OA group, there was no significant difference in peak KAM when walking in the modified shoe as compared to walking barefoot. In the overweight and the healthy weight groups, the peak KAM when walking in the modified shoe was significantly higher than that when walking barefoot (P < 0.001). Irrespective of group, the KAM impulse was significantly reduced when walking in the modified shoe as compared to the control shoe (P < 0.001) and was significantly higher during both shoe conditions as compared to walking barefoot (P < 0.001). There was no change in the KFM between walking conditions for any group.

CONCLUSION

The findings illustrate that a shoe incorporating both a lateral wedge and a variable-stiffness sole can significantly reduce medial knee joint load. Further research examining the effects of these shoes on pain, function, and structural changes in the joint is warranted.

A comparison of the biomechanical effects of valgus knee braces and lateral wedged insoles in patients with knee osteoarthritis

Increases in the external knee adduction moment (EKAM) have been associated with increased mechanical load at the knee and progression of knee osteoarthritis. Valgus knee braces and lateral wedged insoles are common approaches to reducing this loading; however no study has directly compared the biomechanical and clinical effects of these two treatments in patients with medial tibiofemoral osteoarthritis. A cross-over randomised design was used where each intervention was worn by 28 patients for a two week period. Pre- and post-intervention gait kinematic/kinetic data and clinical outcomes were collected to evaluate the biomechanical and clinical effects on the knee joint. The valgus knee brace and the lateral wedged insole significantly increased walking speed, reduced the early stance EKAM by 7% and 12%, and the knee adduction angular impulse by 8.6 and 16.1% respectively. The lateral wedged insole significantly reduced the early stance EKAM compared to the valgus knee brace (p=0.001). The valgus knee brace significantly reduced the knee varus angle compared to the baseline and lateral wedged insole. Improvements in pain and function subscales were comparable for the valgus knee brace and lateral wedged insole. There were no significant differences between the two treatments in any of the clinical outcomes; however the lateral wedged insoles demonstrated greater levels of acceptance by patients. This is the first study to biomechanically compare these two treatments, and demonstrates that given the potential role of knee loading in osteoarthritis progression, that both treatments reduce this but lateral wedge insoles appear to have a greater effect.

The young osteoarthritic knee: dilemmas in management

As a result of increasing life expectancies, continuing physical careers, lifestyles into later life and rising obesity levels, the number of younger patients presenting with osteoarthritis (OA) of the knee is increasing. When conservative management options have been exhausted, the challenge for the orthopedic surgeon is to offer a procedure that will relieve symptoms and allow a return to a high level of function but not compromise future surgery that may be required as disease progresses or prostheses fail and require revision. We discuss the options available to this group of patients and the relative benefits and potential negative points of each. Total knee replacement (TKR) in the young patient is associated with high risk of early failure and the need for future revision surgery. After TKR, most surgeons advise limitation of sporting activities. If osteoarthritis is limited to only one compartment in the knee there may be surgical options other than TKR. Osteotomy above or below the knee may be considered and works by redirecting the load passing through the joint into the relatively unaffected compartment. A unicompartmental knee replacement (UKR) or patella-femoral joint (PFJ) replacement only replaces the articular surfaces in the affected compartment, leaving the unaffected compartments untouched with better preservation of the soft tissues. Which of these options is best for a particular patient depends upon the patient's symptoms, precise pathology, lifestyle, and expectations.

Unloading the osteoarthritic knee with a novel implant system

Medial knee osteoarthritis (OA) is a common disorder often associated with pathologic joint loading. Insoles, braces, and high tibial osteotomy are OA treatments aimed at reducing medial joint loads, but their use and effectiveness are limited. The KineSpring System implant also intends to reduce knee loads in OA patients while overcoming those limitations. The current study was undertaken to test the implant's effect on loads at the knee. Six cadaver knees with Outerbridge Grade I-II medial OA were subjected to simulated gait using a kinematic test system. Knees were tested with and without the medial knee implant while thin film sensors measured medial and lateral femorotibial contact pressures. Significant medial compartment load reductions (134 ± 53 N [P = .002]) were found throughout the stance phase of gait in the treated knee. Significant total joint load decreases (91 ± 40 N [P = .002]) were also observed without substantial changes in lateral compartment loads. These significant reductions of medial and total intra-articular loads are also within clinically effective ranges of other unloading systems. This suggests that the KineSpring System could be a viable treatment for medial knee OA.

The pathophysiology of osteoarthritis: a mechanical perspective on the knee joint

Osteoarthritis (OA) is the most frequent cause of disability in the United States, with the medial compartment of the knee being most commonly affected. The initiation and progression of knee OA is influenced by many factors, including kinematics. In response to loading during weight-bearing activity, cartilage in healthy knees demonstrates spatial adaptations in morphology and mechanical properties. These adaptations allow certain regions of the cartilage to respond to loading; other regions are less well suited to accommodate loading. Alterations in normal knee kinematics shift loading from cartilage regions adapted for loading to regions less well suited for loading, which leads to the initiation and progression of degenerative processes consistent with knee OA. Kinematic variables that are associated with the development, progression, and severity of knee OA are the adduction moment and tibiofemoral rotation. Because of its strong correlation with disease progression and pain, the peak adduction moment during gait has been identified as a target for treatment design. Gait modification offers a noninvasive option for seeking significant reductions. Gait modification has the potential to reduce pain and slow the progression of medial compartment knee OA.

Unloader braces for medial compartment knee osteoarthritis: implications on mediating progression

Background:

For persons with unicompartment knee osteoarthritis (OA), off-unloader braces are a mechanical intervention designed to reduce pain, improve physical function, and possibly slow disease progression. Pain relief is thought to be mediated by distracting the involved compartment via external varus or valgus forces applied to the knee. In so doing, tibiofemoral alignment is improved, and load is shifted off the degenerative compartment, where exposure to potentially damaging and provocative mechanical stresses are reduced.

Objectives:

To provide a synopsis of the evidence documented in the scientific literature concerning the efficacy of off-loader knee braces for improving symptomatology associated with painful disabling medial compartment knee OA.

Search Strategy:

Relevant peer-reviewed publications were retrieved from a MEDLINE search using the terms with the reference terms osteoarthritis, knee, and braces (per Medical Subject Headings), plus a manual search of bibliographies from original and review articles and appropriate Internet resources.

Results:

For persons with combined unicompartment knee OA and mild to moderate instability, the strength of recommendation reported by the Osteoarthritis Research Society International in the ability of off-loader knee braces to reduce pain, improve stability, and diminish the risk of falling was 76% (95% confidence interval, 69%-83%). The more evidence the treatment is effective, the higher the percentage.

Conclusions:

Given the encouraging evidence that off-loader braces are effective in mediating pain relief in conjunction with knee OA and malalignment, bracing should be fully used before joint realignment or replacement surgery is considered. With the number of patients with varus deformities and knee pain predicted to increase as the population ages, a reduction of patient morbidity for this widespread chronic condition in combination with this treatment modality could have a positive impact on health care costs and the economic productivity and quality of life of the affected individuals.

Combined effects of a valgus knee brace and lateral wedge foot orthotic on the external knee adduction moment in patients with varus gonarthrosis

OBJECTIVE

To test the hypothesis that a custom-fit valgus knee brace and custom-made lateral wedge foot orthotic will have greatest effects on decreasing the external knee adduction moment during gait when used concurrently.

DESIGN

Proof-of-concept, single test session, crossover trial.

SETTING

Biomechanics laboratory within a tertiary care center.

PARTICIPANTS

Patients (n=16) with varus alignment and knee osteoarthritis (OA) primarily affecting the medial compartment of the tibiofemoral joint (varus gonarthrosis).

INTERVENTIONS

Custom-fit valgus knee brace and custom-made full-length lateral wedge foot orthotic. Amounts of valgus angulation and wedge height were tailored to each patient to ensure comfort.

MAIN OUTCOME MEASURES

The external knee adduction moment (% body weight [BW]*height [Ht]), frontal plane lever arm (cm), and ground reaction force (N/kg), determined from 3-dimensional gait analysis completed under 4 randomized conditions: (1) control (no knee brace, no foot orthotic), (2) knee brace, (3) foot orthotic, and (4) knee brace and foot orthotic.

RESULTS

The reduction in knee adduction moment was greatest when concurrently using the knee brace and foot orthotic (effect sizes ranged from 0.3 to 0.4). The mean decrease in first peak knee adduction moment compared with control was .36% BW*Ht (95% confidence interval [CI], -.66 to -.07). This was accompanied by a mean decrease in frontal plane lever arm of .59cm (95% CI, -.94 to -.25).

CONCLUSIONS

These findings suggest that using a custom-fit knee brace and custom-made foot orthotic concurrently can produce a greater overall reduction in the knee adduction moment, through combined effects in decreasing the frontal plane lever arm.

Contralateral cane use and knee joint load in people with medial knee osteoarthritis: the effect of varying body weight support

OBJECTIVE

To evaluate the effect of varying body weight support (BWS) with contralateral cane use on medial knee load, measured by external knee adduction moment (KAM), in medial knee osteoarthritis (OA) participants. Influences of cane use technique, pain and malalignment on the cane's load-reducing effects were investigated.

METHOD

Participants (n=23) underwent three-dimensional gait analysis to measure KAM peaks (early and late stance) and impulse. Unaided walking was firstly analyzed. Following cane use training, participants placed pre-determined magnitudes of BWS through the cane (10%, 15% and 20% in random order), with visual feedback provided via a force-instrumented cane and projection screen. Contributions of cane use technique (peak BWS magnitude and timing, cane impulse (BWS∗time) anterior and lateral cane distance from limb) and Western Ontario McMaster Universities OA Index (WOMAC) pain and malalignment to KAM outcomes were evaluated using linear mixed models.

RESULTS

Cane use reduced all KAM variables, with a dose-response effect apparent. Cane BWS impulse was important in reducing the early stance peak KAM (P<0.001), peak BWS for late stance KAM (P<0.001) and both BWS measures for KAM impulse reductions (P<0.001). Variables contributing to efficacy of load-reduction differed across outcomes. Generally, greater reductions were achieved with longer lateral cane distances, peak BWS timing similar to KAM peaks, and shorter anterior cane distances. Greater pain and varus alignment improved load-reduction for some outcomes.

CONCLUSION

Contralateral cane use significantly reduced medial knee load, with a dose-response effect. Medial knee OA patients should be encouraged to maintain greater BWS across stance, with cane placement more lateral for optimum benefit.

Update in surgery for osteoarthritis of the knee

Osteoarthritis is a leading cause of disability with incidence and prevalence rising in most nations. Management to address the degenerative joint is stratified according to degree of severity of involvement and always begins with non-surgical modalities before progressing through a range of surgeries, including arthroscopy, osteotomy, unicompartmental and total knee replacement. Predictability of results depends on the type of procedure with total joint replacement giving the most sustainable relief from symptoms, improvement of function and longevity of construct. Obesity is a health priority in developed countries where it is overrepresented in patients presenting for joint replacement. Complications, poor patient satisfaction and joint function can be directly attributable to obesity. Efforts to address obesity should be considered as part of the approach to managing osteoarthritis.

Long-term results of an unloader brace in patients with unicompartmental knee osteoarthritis

Previously, we reported a prospective study of 30 patients with unicompartmental osteoarthritis of the knee treated nonoperatively with an unloader brace and average follow-up of 2.7 years. Although the initial study suggested short-term benefit according to pain and function measures, the objective of the current study was to evaluate these same patients via telephone questionnaire to determine the status of their brace use and any surgical procedures on the affected limb. Because we noted that even at 2.7 years, some patients opted for surgical management despite good response to bracing, our hypothesis was that these patients would not opt for long-term brace wear. Twenty-four of 30 patients were available for reporting based on telephone interview; in addition, we talked with family members of 5 patients who had died. When evaluated at 2.7 years, 41% of the 30 patients were still using the brace, 35% had discontinued brace use, and 24% had undergone arthroplasty. When contacted for the follow-up survey at an average of 11.2 years, 17 (58.6%) of the 29 patients had undergone arthroplasty. The mean interval between initial evaluation and arthroplasty was 3.9 years. In addition, 7 patients had undergone arthroscopic surgery. Importantly, none of the patients were still wearing the brace. The use of an unloader brace is effective in providing short-term pain relief and improved function; however, most patients subsequently opt for total knee replacement on the symptomatic knee.

Medial knee osteoarthritis treated by insoles or braces: a randomized trial

BACKGROUND

There is controversial evidence regarding whether foot orthoses or knee braces improve pain and function or correct malalignment in selected patients with osteoarthritis (OA) of the medial knee compartment. However, insoles are safe and less costly than knee bracing if they relieve pain or improve function.

QUESTIONS/PURPOSES

We therefore asked whether laterally wedged insoles or valgus braces would reduce pain, enhance functional scores, and correct varus malalignment comparable to knee braces.

PATIENTS AND METHODS

We prospectively enrolled 91 patients with symptomatic medial compartmental knee OA and randomized to treatment with either a 10-mm laterally wedged insole (index group, n = 45) or a valgus brace (control group, n = 46). All patients were assessed at 6 months. The primary outcome measure was pain severity as measured on a visual analog scale. Secondary outcome measures were knee function score using WOMAC and correction of varus alignment on AP whole-leg radiographs taken with the patient in the standing position. Additionally, we compared the percentage of responders according to the OMERACT-OARSI criteria for both groups.

RESULTS

We observed no differences in pain or WOMAC scores between the two groups. Neither device achieved correction of knee varus malalignment in the frontal plane. According to the OMERACT-OARSI criteria, 17% of our patients responded to the allocated intervention. Patients in the insole group complied better with their intervention. Although subgroup analysis results should be translated into practice cautiously, we observed a slightly higher percentage of responders for the insole compared with bracing for patients with mild medial OA.

CONCLUSIONS

Our data suggest a laterally wedged insole may be an alternative to valgus bracing for noninvasively treating symptoms of medial knee OA.

LEVEL OF EVIDENCE

Level I, therapeutic study. See the Guidelines for Authors for a complete description of level of evidence.