Unloader Knee Brace Research Articles

Unloader brace or high tibial osteotomy in the treatment of the young patient with medial knee osteoarthritis: a randomized controlled trial.

For medial knee osteoarthritis (OA), operative and nonoperative treatment options are available. Two widely applied unloading therapies are a valgus unloader brace and a high tibial osteotomy (HTO). We aimed to compare the effects of a valgus unloader knee brace with an HTO on knee pain after 1 year in patients with symptomatic medial knee OA. We recruited patients from 9 Dutch hospitals between August 2014 and February 2019 for an open-labeled multi-center randomized controlled trial (Dutch Trial Register NL4200). Patients aged 18 to 65 years with symptomatic medial compartmental knee OA were randomized to either a valgus unloader brace or an HTO. The primary outcome was the pain subscale of the Knee injury and Osteoarthritis Outcome score (KOOS) after 1 year. Patients were evaluated at 3, 6, 9, 12, and 24 months. 51 patients were included in the study, of whom 23 were randomized to the unloader brace and 28 to the HTO. The HTO, compared with the unloader brace, showed a significant and clinically relevant difference at 12 months of follow-up in KOOS pain of -28 (95% confidence interval -43 to -13). We found that, on group level, an HTO is more effective in reducing knee pain than an unloader brace after 12 months.

Electronics-Free Soft Robotic Knee Brace for Dynamic Unloading During Gait for Knee Osteoarthritis: A Proof-of-Concept Study

Abstract We present a novel electronics-free soft robotic knee brace which employs a closed-loop fluidic regenerative (CLFR) system for dynamic unloading in unicompartmental tibiofemoral osteoarthritis (OA). The existing dynamic unloaders are bulky, large, and heavy, and have low compliance likely due to the use of an electrical control box, which is eliminated in the CLFR system. The system consists of a commercial unloading knee brace, a spring-loaded bellow inserted under the heel inside a shoe, a soft-fluidic actuator (bladder), and tubing for fluid transfer. The novelty lies in the fact that the user's body weight (self-powered) compresses the bellow to provide energy to inflate the air bladder placed at the knee. As a result, the yielded pressure unloads the undesirable forces due to knee OA during the stance phase of gait while strategically applying no forces during the swing phase. The knee bladder contact pressure/force, the system response time, and the durability were evaluated via contact pressure measurements for six systems with varying bellow volumes and either pneumatic or hydraulic configurations. All systems produced safe pressure outputs for human skin within a tested bodyweight range of 60–90 kg. Pneumatic and hydraulic systems achieved 250 ms and 400 ms pressurization response times, respectively. During cyclic loading, pneumatic and hydraulic systems demonstrated less than 1% and ∼10% pressure loss, respectively. Overall, the CLFR system created a promising electronics-free solution for dynamically unloading the knee during gait, indicating a potential new paradigm for knee braces.

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

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. 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. 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. 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. 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.

Evaluation of the Effect of Knee Unloader Orthoses, Lateral Wedge Insoles, and Ankle Foot Orthoses on Pain, Function, and Knee Adduction Moment in Subjects with Medial Compartment Knee Osteoarthritis: A Literature Review

ABSTRACT Introduction Osteoarthritis (OA) is a destructive joint disease and a major cause of pain in the elderly. The use of supportive orthoses including valgus knee brace, lateral wedged insole, and ankle-foot orthosis (AFO) is a common treatment for these people. The purpose of this review of the literature is to evaluate the effect of orthoses on pain, function, and adduction moment (AM) of individuals with medial knee OA. Method The search was conducted among articles published from 2010 to 2021 in bibliographic online databases including ISI Web of Science, PubMed, Scopus, and Google Scholar. The potential titles and abstracts were reviewed based on the study inclusion criteria. All randomized controlled trial (RCT) studies on the effectiveness of valgus knee brace, AFO, and lateral wedged insoles in subjects with medial knee OA were reviewed. The search terms were OA, medial knee osteoarthritis, medial joint arthritis, unloader knee brace, valgus knee brace, knee sleeve, lateral wedge insole, AFO, ankle-foot orthosis, function, pain, alignment, kinetic, kinematic, and AM. Result Forty-two articles were reviewed to determine the current research process. Thirteen studies evaluated the effect of lateral wedge insole on pain, function, and AM in subjects with medial compartment knee OA. Ten studies evaluated unloader knee braces. Nine studies evaluated unloader knee brace compared with lateral wedge insole, three studies evaluated AFO, and seven studies examined the combination of knee braces and lateral wedge insoles on pain, function, and AM. Conclusion All three orthoses in short-term follow-up reduced the AM in subjects with medial knee OA. Lateral wedge insoles did not support pain reduction in studies. The results of this study showed that knee braces may have a more lasting effect on the knee joint in the long run than lateral wedge insoles. Although the number of studies that evaluated the effect of AFOs on outcomes of subjects with knee OA is low, this intervention was found to be effective in relieving pain and reducing AM. Clinical Relevance In clinical studies, clinical relevance in patients with medial knee OA, orthoses effectively reduced external knee AM and pain sensation during daily activities. Thus, use of orthoses effectively supports conservative treatment in medial knee OA.

A developed multibody knee model for unloading knee with cartilage penetration depth control.

Unloader knee braces could relieve pain by decreasing the medial knee loading. Particularly for knee osteoarthritis (KOA) patients, this study investigates the relevance of the knee model after identifying the most influential parameter. Since KOA causes the cartilage in a joint to lose its elasticity and thickness, the lack of normal bone-to-bone separation can be painful. We believe that cartilage penetration depth control is an impactful strategy in this research. Moreover, the knee contact force in KOA is fewer than in healthy knees, confirming that the contact force control cannot be a straight factor. Therefore, a biomechanical human knee model is developed, and a generic procedure for dynamic analysis of contact problems in combination with the musculoskeletal model is introduced. The developed model includes the geometric expression of collision curves and an algorithm for determining collision points. This presentation addresses cartilage penetration depth and contact force calculation through nonlinear discontinuous contact law. In view of this, femur and tibia's relative motion is analyzed through the combined collision reactions of cartilage and bone in the knee. In the simulation, maximum penetration depth in a healthy knee is reported to be 0.795 mm, while in a 75% KOA is 0.521 mm, including 0.5 mm cartilage-cartilage contact and 0.021 mm bone-bone contact. The top unloading 852 N is achieved, reducing penetration depth to 0.45 mm, avoiding bone-bone contact. This proposed procedure with low computation gives us a suitable analysis method for designing knee assistive devices.

Efficacy of unloader knee orthosis and lateral wedge insole on static balance in medial knee osteoarthritis

Background Medial knee osteoarthritis can contribute to pain and stiffness, interfere with balance and limit functional activities of daily living. Unloader knee orthosis or lateral wedged insoles are current conservative approaches used to treat these conditions. The aim of this study was to identify and compare the effects of them on the balance parameters. Methods 66 subjects with mild to moderate medial knee osteoarthritis were randomly assigned to wear unloader knee brace or full-length 6° lateral wedge insole. Primary outcome balance parameters were stability %, path length and average velocity of center of pressure and mobility score which were investigated by HUMAC® Balance and Tilt system. Secondary outcome measures were knee function score using Knee Injury and Osteoarthritis Outcome Score scale. Assessment was performed at baseline and six months post orthotic intervention period. Findings Both orthoses improved all parameters compared to the baseline condition (p < 0.05). Unloader knee orthosis showed a significant improvement in all balance parameters compared to lateral wedged insoles (p < 0.001) except mobility scores (p = 0.527). Except activities of daily living (p = 0.752) and sports and recreational activities (p = 0.437), unloader knee orthosis had a greater effect on the pain (p = 0.002) and symptoms (p < 0.001) sub scales than lateral wedged insoles. However, quality of life sub-scale scores for insoles were more effective than the knee orthosis. Interpretation Unloader knee orthosis improved balance and knee function scores more than lateral wedged insole, though both orthoses produced significantly improved results compared to baseline assessment.

Design and Preliminary Implementation of an Air Microfluidics Enabled Soft Robotic Knee Brace Towards the Management of Osteoarthritis.

A dynamic and low-profile unloader tibiofemoral knee brace is designed and prototyped by synergizing concepts from the fields of microfluidics and soft robotics. Microfluidics provides strategies for miniaturization and multiplexing while soft robotics afford the tools to create soft fluidic actuators and allow compliant and inherently safe robotic assistance as part of clothing. The unloader knee brace provides dynamic response during the gait cycle, where a three-point leverage torque is provided only during the stance phase to contribute to joint stability when required and enhance comfort and compliance.Clinical Relevance- This novel soft robotic brace has the potential to reduce device abandonment due to aesthetics, user non-compliance and discomfort due to a constant three-point leverage torque during the gait cycle. Also, this air microfluidics enabled soft robotic knee brace could be expanded upon to improve the efficacy of braces in general and augment the effects of physical therapy, rehabilitation and treatment of musculoskeletal conditions.

Effect of a tri compartment unloader knee brace on knee moments and quadriceps activity during a chair rise and lower and stair descent in individuals with knee osteoarthritis

Purpose: Osteoarthritis (OA) is the most common joint disease in adults. Cartilage loss in OA afflicted joints causes pain, disability and reduced quality of life. The knee is the most common location of OA, with the majority of cases being bi- and tri- compartment knee OA. Knee pain associated with OA has a mechanical component and excessive joint loading induces knee pain. The Levitation “Tri-Compartment Unloader” (TCU) knee brace (Spring Loaded Technology) was designed to reduce pain in individuals suffering from multi-compartment knee OA.

Design Evaluation of a Novel Multicompartment Unloader Knee Brace.

Knee osteoarthritis (OA) is a significant problem in the aging population, causing pain, impaired mobility, and decreased quality of life. Conservative treatment methods are necessary to reduce rapidly increasing rates of knee joint surgery. Recommended strategies include weight loss and knee bracing to unload knee joint forces. Although weight loss can be beneficial for joint unloading, knee OA patients often find it difficult to lose weight or begin exercise due to knee pain, and not all patients are overweight. Unicompartment offloader knee braces can redistribute joint forces away from one tibiofemoral (TF) compartment; however, <5% of patients have unicompartmental tibiofemoral osteoarthritis (TFOA), while patients with isolated patellofemoral or multicompartmental OA are much more common. By absorbing body weight (BW) and assisting the knee extension moment using a spring-loaded hinge, sufficiently powerful knee-extension-assist (KEA) braces could be useful for unloading the whole knee. This paper (1) describes the design of a spring-loaded tricompartment unloader (TCU) knee brace intended to provide unloading in all three compartments of the knee while weight-bearing, (2) measures and compares the force output of the TCU against the only published and commercially available KEA brace, and (3) calculates the static unloading capacity of each device. The TCU and KEA braces delivered maximum assistive moments equivalent to reducing BW by approximately 45 and 6 lbs, respectively. The paper concludes that sufficiently powerful spring-loaded knee braces show promise in a new class of multicompartment unloader knee orthoses, capable of providing a clinically meaningful unloading effect across all three knee compartments.

Comparison of the effect of Western-made unloading knee brace with physical therapy in Asian patients with medial compartment knee osteoarthritis—A preliminary report

To compare the effect of unloading knee brace with physical therapy (PT) in Asian patients with osteoarthritis (OA) of the knee. This is a non-random, two-group comparative study. Patients with medial compartment knee OA (n=41) were assigned to either the brace group (n=20) or PT group (n=21). Patients in the brace group were fitted with an unloading knee brace for three months and the PT group received a 60-min session of physiotherapy over the affected knee, three times a week, for three months. The primary outcome measures were the pain visual analogue scale (VAS) and the Western Ontario McMaster University Osteoarthritis Index (WOMAC); the second outcome measures were the 36-item Short-Form Health Survey (SF-36) and patient's satisfaction. The patients were evaluated at baseline, and at one month and three months. Group comparison showed no significant difference regarding pain VAS, WOMAC, SF-36, and patient's satisfaction, except stiffness in WOMAC (P=.006) and social functioning in SF-36 (P=.007). Time and group interaction revealed significant differences only in general health (P=.007) and mental health (P=.006) of SF-36. Within-group comparison found that pain VAS and WOMAC decreased significantly at one months and three months in both groups. The effect of brace fitting in patients with knee OA was similar to that of physical therapy. A Western-made unloading knee brace is acceptable in some Asian people with knee OA. NCT02712710.

Development of a Robotic Unloader Brace for Investigation of Conservative Treatment of Medial Knee Osteoarthritis.

Knee osteoarthritis (KOA) is a painful and debilitating condition that is associated with mechanical loading of the knee joint. Numerous conservative treatment strategies have been developed to delay time to total joint replacement. Unloader braces are commonly prescribed for medial uni-compartmental KOA, however their evidence of efficacy is inconclusive and limited by user compliance. Typical commercial braces transfer load from the medial knee compartment to the lateral knee compartment by applying a continuous brace abduction moment (BAM). We propose that brace utilization and effectiveness could be improved with a robotic device that intelligently modulates BAM in real time over the course of a step, day, and year to better protect the knee joint, improve pain relief, and increase comfort. To this end, we developed a robotic unloader knee brace ABLE (active brace for laboratory exploration) to flexibly emulate and explore different active and passive brace behaviors that may be more efficacious than traditional braces. The system is capable of modulating BAM within each step per researcher defined unloading profiles. ABLE was realized as a lightweight orthosis driven by an off-board system containing a servo motor, drive, real-time controller, and host PC. Frequency response and intra-step trajectory tracking during level-ground walking were evaluated in a single healthy human subject test to verify system performance. The system tracked BAM vs percent gait cycle trajectories with a root mean square error of 0.18 to 0.58 Nm for conditions varying in walking speed, 85-115% nominal, and trajectory peak BAM, 2.7 to 8.1 Nm. Biomechanical and subjective outcomes will be evaluated next for KOA patients to investigate how novel robotic brace operation affects pain relief, comfort, and KOA progression.

Influence of an unloader brace on lower limb electromyographic activity in individuals with predominant lateral osteoarthritis after anterior cruciate ligament reconstruction

ObjectiveTo determine the immediate effects of a varus unloader knee brace on lower-limb electromyographic activity in individuals with lateral knee osteoarthritis and valgus malalignment after anterior cruciate ligament reconstruction. MethodsElectromyographic data were recorded in 19 individuals with lateral knee osteoarthritis and valgus malalignment after anterior cruciate ligament reconstruction during walking under three conditions: (i) no brace, (ii) unadjusted brace (no varus adjustment), and adjusted brace (varus adjustment). Variables of interest were statistically analyzed using repeated measures analysis of variance. ResultsThere were no significant differences in muscle co-contraction between the three test conditions. The adjusted brace resulted in delayed offset of gluteus maximus (mean difference [95% CI]: 72ms [24, 119]), and earlier onset of gluteus medius (59ms [21, 97]) compared to no brace. The adjusted brace delayed onset of lateral gastrocnemius compared to no brace (53ms [28, 78]) and the unadjusted brace (39ms [7, 71]) and reduced average activation amplitude of gluteus maximus (−4mV [−6, −1]) and lateral gastrocnemius (−9mV [−16, −2]) compared to no brace. ConclusionsThe unloader brace did not produce significant changes in muscle co-contraction in individuals with lateral knee osteoarthritis and valgus malalignment after anterior cruciate ligament reconstruction. Significant changes in gluteal and gastrocnemius muscle activation timing and amplitude were observed, however, it is not clear whether these changes are of clinical importance.

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

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. After 2weeks of daily use of the unloader brace, ten varus knee OA patients (age 52 ± 8years) walked with and without the brace on an instrumented treadmill, while biplane radiographs of the OA knees were acquired at 100Hz. 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 1000Hz. 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. Medial compartment DJS was significantly greater with the unloader brace than without the brace during gait (P = 0.005). The average difference was 0.3mm (95% confidence interval 0.1-0.4mm). 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. 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. III.

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.

An Update on Unloading Knee Braces in the Treatment of Unicompartmental Knee Osteoarthritis from the Last 10 Years: A Literature Review.

Background The incidence of osteoarthritis is increasing and it is one of the most common causes of chronic conditions. Total knee replacement is the mainstay of treatment for end-stage knee osteoarthritis; however, with long waiting lists and high levels of dissatisfaction, a treatment like knee braces could potentially delay surgery. Unicompartmental knee osteoarthritis is associated with misalignment of the knee, and unloader bracing has been recommended by various guidelines to correct this misalignment. The aim of this report was to provide an update of evidence from the past 10 years on knee braces. Methods MEDLINE/EMBASE search was performed from the past 10 years. Results We reviewed the evidence from 14 published articles. Almost all articles supported knee brace use and showed it to decrease pain, improve function, and improve the quality of life of patients. One study in 2017 followed patients for long term and found knee bracing to be more cost effective than total knee replacement, and could replace the need for surgery. Several minor complications were reported with bracing, like soft tissue irritation, which could be due to poor fitting. A management strategy for this could be regular follow-up at a nurse-led clinic. Conclusions Unloader braces are an economical and effective treatment for unicompartmental knee osteoarthritis. They can significantly improve a patient's quality of life and potentially delay the need for surgery. Patients should be managed with a multidisciplinary approach with conservative management and knee bracing, before surgery is considered.

Unloader Knee Brace Increases Medial Compartment Joint Space During Gait In Knee Osteoarthritis Patients

Objectives:Clinical outcome measures suggest the unloader brace provides small-to-moderate improvements in pain and function in varus knee osteoarthritis (OA) patients. However, controversy still exists as to whether the brace has the real effect of increasing tibiofemoral joint space in the medial compartment during functional activity. As a limitation, the previous studies did not report ground reaction forces (GRF) with and without the brace, which could be a confounding factor affecting joint space. Therefore, the purpose of the present study was to investigate the effect of an unloader brace on dynamic joint space in medial compartment in OA patients while simultaneously recording GRF during gait. The hypotheses were (1) dynamic joint space in the medial compartment would be greater with the unloader brace than without the brace during gait, and (2) GRF during gait would be smaller with the brace than without the brace.Methods:Ten varus knee OA patients were enrolled (Age: 52±8 years). After minimum 2-week daily use of the unloader brace, subjects walked (1.0 m/s) on an instrumented treadmill while biplane radiographs of the OA knees were acquired at 100 Hz. Tibiofemoral motion was determined from the biplane radiographs from initial contact to terminal stance phase (gait cycle: 0-40%) using a previously validated model-based tracking process. Dynamic joint space measurement in the medial compartment was performed using previously reported method. Briefly, the medial tibial plateau was divided into 9 sub-regions (Figure 1A) and the average minimum distance between femur and tibia subchondral bone was calculated in each region. The region with the smallest joint space over the three walking trials was selected for the analysis. GRF during gait were collected at 1000 Hz and normalized by each subject’s body weight. Output parameters were averaged over 10% intervals of the gait cycle. Two-way repeated measures ANOVA (gait cycle x brace condition) was used to explore differences in medial compartment dynamic joint space and GRF between the 2 conditions (unbraced and braced). Post-hoc paired t-tests identified the differences between the 2 conditions during the same gait cycle period. Significance level was set as P < 0.05. A subjective questionnaire for the brace usage was collected at the time of the test.Results:The dynamic joint space in the medial compartment was significantly greater with the unloader brace than without the brace during gait (P = 0.004) (Table 1, Figure 1B). The average difference between the 2 conditions was 0.27 mm (95% confidential interval: 0.12-0.43). No significant difference was observed in terms of GRF between unbraced and braced conditions. The questionnaire showed participants felt reduced pain (4.1±0.7 out of 5 scale) and were comfortable (3.8±0.8 out of 5) when wearing the brace.Conclusion:The unloader knee brace induced a small but significant increase in medial dynamic joint space during gait. Furthermore, no differences in GRF during gait were found between unbraced and braced conditions, indicating that the increase of medial joint space with bracing was not due to decreased limb-loading during gait, but instead due to the brace use itself. These results suggest that the OA unloader brace may reduce medial compartment joint loading during dynamic loading activities.Figure 1.(A) Medial compartment regions used to calculate dynamic joint space. The medial tibial plateau was divided into 9 sub-regions, and the average joint space in each region was obtained over every 10% of gait cycle. The regions with the smallest joint space (region 5 in 9/10 subjects) was selected for the analysis. (B) The instantaneous dynamic joint space during gait at 15% of the gait cycle for one subject, demonstrating increased medial compartment joint space in the braced condition.Table 1.Results of medial compartment dynamic joint space and ground reaction forces during gait. *Statistically significant difference (vs unbraced condition)Gait cycleMedial compartment dynamic Joint space (mm)Ground reaction forces / Body weightUnbracedBracedP-valueUnbracedBracedP-value0-10%2.8 ± 0.93.2 ± 1.0*0.0070.55 ± 0.11*0.56 ± 0.12*N/A10-20%2.4 ± 0.82.6 ±0.8*0.0010.94± 0.11*0.94 ± 0.08*20-30%2.4 ± 0.82.6 ±0.7*0.0280.87 ± 0.09*0.92 ± 0.08*30-40%2.3± 0.72.6 ±0.6*0.0170.90 ± 0.08*0.91 ± 0.09*Overall2.5 ± 0.82.8 ±0.7*0.0040.81 ± 0.04*0.83 ± 0.04*0.15

A Simple Method for Measuring the Changeable Mechanical Action of Unloader Knee Braces for Osteoarthritis

PurposeToday's orthotics should be designed to apply the external orthosis moment to the knee joint solely during the stance phase instead of the entire gait cycle. The aim of this study was to validate the reliability of a simple device for measuring forces at the leg–orthosis interface and describe the behavior of an innovating dynamic unloader knee brace built to interrupt its mechanical action during large knee flexion (swing phase of gait). MethodsA compression testing machine was used to apply known (standard) forces to the device (modeled forces) and the results were compared. ResultsThe low absolute mean bias (∼4%), the narrow agreement limits associated with the Bland and Altman analysis as well as the significant linear correlation (r=0.99; p<0.001) validate the agreement between standard and modeled forces. Likewise, the low standard error of measurement between trials (∼1.3%) and the intraclass correlation coefficient (1.00) reflect high test-retest reliability. ConclusionThese results demonstrate the validity of the proposed device for measuring constraints induced by the dynamic unloader knee brace. An example of an application is provided through an orthosis moment calculation using kinematic data, which reveal a changeable mechanical action, necessary to improve comfort resulting in potentially better compliance.

Medial Unloader Braces and Lateral Heel Wedges Do not Alter Gait Biomechanics in Healthy Young Adults.

Context: Orthotic devices such as medial unloader knee braces and lateral heel wedges may limit cartilage loading following trauma or surgical repair. However, little is known regarding their effects on gait biomechanics in young, healthy individuals who are at risk of cartilage injury during physical activity due to greater athletic exposure compared with older adults. Objective: Determine the effect of medial unloader braces and lateral heel wedges on lower-extremity kinematics and kinetics in healthy, young adults. Design: Cross-sectional crossover design. Setting: Laboratory setting. Patients: Healthy, young adults who were recreationally active (30min/d for 3d/wk) between 18 and 35 years of age, who were free from orthopedic injury for at least 6 months, and with no history of lower-extremity orthopedic surgery. Interventions: All subjects completed normal over ground walking with a medial unloader brace at 2 different tension settings and a lateral heel wedge for a total of 4 separate walking conditions. Main Outcome Measures: Frontal plane knee angle at heel strike, peak varus angle, peak internal knee valgus moment, and frontal plane angular impulse were compared across conditions. Results: The medial unloader brace at 50% (-2.04° [3.53°]) and 100% (-1.80° [3.63°]) maximum load placed the knee in a significantly more valgus orientation at heel strike compared with the lateral heel wedge condition (-0.05° [2.85°]). However, this difference has minimal clinical relevance. Neither of the orthotic devices altered knee kinematics or kinetics relative to the control condition. Conclusions: Although effective in older adults and individuals with varus knee alignment, medial unloader braces and lateral heel wedges do not influence gait biomechanics in young, healthy individuals.

New Adjustable Unloader Knee Brace and Its Effectiveness

Unloader knee braces are prescribed for patients with unicompartmental osteoarthritis of the knee. These braces aim to reduce pain in patients by applying a coronal moment to the knee to unload the symptomatic knee compartment. However, existing unloading mechanisms use straps that go directly behind the knee joint, to apply the needed moment. This can impinge on the popliteal artery and peroneal nerves thereby causing discomfort to the patient. Hence, these braces cannot be worn for prolonged periods of time. This research focused on developing a new knee brace to improve comfort while unloading the osteoarthritic knee. A new knee brace was developed that uses a four-point bending approach to unload the knee. In this brace, unloading can be adjusted, and the unloading mechanism is away from the joint. The new brace was tested on a cadaver specimen to quantify its capability to unload the knee compartment. The brace was also worn by a patient with osteoarthritis who subjectively compared it to his existing unloader brace. During cadaver testing, the new brace design could reduce the force exerted on the medial condyle by 25%. Radiographic images of the patient's knee confirmed that the brace unloaded the medial condyle successfully. The patient reported that the new brace reduced pain, was significantly comfortable to wear and could be used for a longer duration in comparison to his existing brace.

Unloading knee brace is a cost-effective method to bridge and delay surgery in unicompartmental knee arthritis

BackgroundUnloading knee braces can provide good short-term pain relief for some patients with unicompartmental osteoarthritis (UOA). Their cost is relatively small compared with surgical interventions. However, no previous studies have...