Knee Orthosis Research Articles

Development and Evaluation of a Powered Artificial Gastrocnemius for Transtibial Amputee Gait

Existing robotic transtibial prostheses provide only ankle joint actuation and do not restore biarticular function of the gastrocnemius muscle. This paper presents the first powered biarticular transtibial prosthesis, which is a combination of a commercial powered ankle-foot prosthesis and a motorized robotic knee orthosis. The orthosis is controlled to emulate the human gastrocnemius based on neuromuscular models of matched nonamputees. Together with the ankle-foot prosthesis, the devices provide biarticular actuation. We evaluate differences between this biarticular condition and a monoarticular condition with the orthosis behaving as a free-joint. Six participants with transtibial amputation walk with the prosthesis on a treadmill while motion, force, and metabolic data are collected and analyzed for differences between conditions. The biarticular prosthesis reduces affected-side biological knee flexion moment impulse and hip positive work during late-stance knee flexion, compared to the monoarticular condition. The data do not support our hypothesis that metabolism decreases for all participants, but some participants demonstrate large metabolic reductions with the biarticular condition. These preliminary results suggest that a powered artificial gastrocnemius may be capable of providing large metabolic reductions compared to a monoarticular prosthesis, but further study is warranted to determine an appropriate controller for achieving more consistent metabolic benefits.

Effects of Use of Prophylactic Knee Orthoses among Ice Hockey Players in Switzerland

Introduction: The use of prophylactic knee orthoses is very common among Swiss ice hockey players to prevent recurrent lesions of the medial collateral ligament (MCL) and the anterior cruciate ligament (ACL). However, their effects are still widely discussed in the literature. Purpose of the Study: The purpose of this study is to assess the feasibility of a given protocol (recruitment, resources, data management, surveys...) for a future national study and to present the preliminary results of the prophylactic orthotics effects on recurrent injuries. Methods: Retrospective epidemiological pilot study. Inclusion criteria: all team players of the second and third divisions in Wallis, except for goalkeepers and underage players. Exposure times correspond to the number of played matches, with an estimation of 0.3 hours of actual play time per game. Feasibility was assessed based on criteria previously defined. Recurrent injuries were divided into three groups: (GA: without orthosis; GB: periodic orthosis; GC: permanent orthosis). Quantitative data, incidence of recurrent injuries and incidence ratio were calculated per 1000 hours of game using the Stata® software programme. Results: Four out of five feasibility criteria were fulfilled. Quantitative data shows that 66.2 % of the summoned players (n=80) were present and all of them took part in the study. Twenty-five MCL and ACL injuries (68 % orthosis wearers) have been included, among which 28 % were recurrences. Incidence rate ratio (IRR) of GA on GB=0.153 (p=0.021); GA on GC = 2.34e-08 (p = 0.00). Discussion and conclusion: A national study is feasible by including minor changes. Recurrent injuries can be prevented in a significant way by wearing an orthosis. However, due to the small sample size, these results must be taken with caution.

Knee Impedance Modulation to Control an Active Orthosis Using Insole Sensors.

Robotic devices for rehabilitation and gait assistance have greatly advanced with the objective of improving both the mobility and quality of life of people with motion impairments. To encourage active participation of the user, the use of admittance control strategy is one of the most appropriate approaches, which requires methods for online adjustment of impedance components. Such approach is cited by the literature as a challenge to guaranteeing a suitable dynamic performance. This work proposes a method for online knee impedance modulation, which generates variable gains through the gait cycle according to the users’ anthropometric data and gait sub-phases recognized with footswitch signals. This approach was evaluated in an active knee orthosis with three variable gain patterns to obtain a suitable condition to implement a stance controller: two different gain patterns to support the knee in stance phase, and a third pattern for gait without knee support. The knee angle and torque were measured during the experimental protocol to compare both temporospatial parameters and kinematics data with other studies of gait with knee exoskeletons. The users rated scores related to their satisfaction with both the device and controller through QUEST questionnaires. Experimental results showed that the admittance controller proposed here offered knee support in 50% of the gait cycle, and the walking speed was not significantly different between the three gain patterns (p = 0.067). A positive effect of the controller on users regarding safety during gait was found with a score of 4 in a scale of 5. Therefore, the approach demonstrates good performance to adjust impedance components providing knee support in stance phase.

Efficacy of a knee orthosis that uses an elastic element.

In this study, we evaluate the support effect of a knee orthosis that uses the elasticity element from the perspective of human motor control. The speeds during level-ground walking and the angles during slope walking were varied during the experiments. It was observed that the support effect was remarkable at 4 km/h during the level-ground walking. In particular, at 12° during slope walking, the strength of the stretching muscle decreased for the knee joint in the stance phase and the hip joint in the swing phase. The results show that this orthosis exhibits a different effect from the conventional type adjustment to damping in the swing phase.

An algorithm to improve knee orthosis prescription for oa patients

An algorithm to improve knee orthosis prescription for oa patients

Exercise using a robotic knee orthosis in stroke patients with hemiplegia.

[Purpose] The Robotics Knee Orthosis (RKO) is a knee–ankle–foot orthosis with active robot assisting technology. The purpose of this study is to examine the effects of exercise with the RKO (RKO-exercise) in stroke patients with hemiplegia. [Subjects and Methods] Participants were nine stroke patients with hemiplegia, residing in a convalescent rehabilitation ward. The duration of the RKO-exercise program was 10 days. Participants were evaluated three times prior to intervention, once after intervention, and one month post intervention. Each session consisted of standard-of-care physical therapy for 60 minutes and RKO-exercise for 20 minutes. Dependent variables were 10-meter gait speed, cadence, Berg Balance Scale (BBS) score, stride length, the absolute value of left-right symmetry of the step length, and one-leg support period while walking. Data were analyzed using a one-way repeated measures ANOVA. [Results] Stride length, left-right symmetry of the step length, and one-leg support period while walking changed following the RKO exercise program. 10-meter walking speed, cadence, percentage of one-leg support period (affected side), and BBS changed significantly at one month post treatment time points. [Conclusion] It is expected that RKO-exercise helps recovery process after the stroke. RKO-exercise effectively treats impaired mobility in patient status-post stroke.

Gait Identification by Inertial Sensors for Control of Adaptive Knee Orthosis Device

Gait Identification by Inertial Sensors for Control of Adaptive Knee Orthosis Device

Transparency enhancement for an active knee orthosis by a constraint-free mechanical design and a gait phase detection based predictive control

This paper proposes a novel mechanical design of a lower limb exoskeleton device which prevents the residual stresses due to arthro-kinematics movements of synovial joints and by the way allows effective compensation for dynamic disturbances in osteo-kinematic movements of the wearer. Here, the exoskeleton is only actuated at the knee joints to provide assistive torques, which are required to assist the anatomical joint motion and to increase the transparency of the device. Dynamic simulations of a virtual human equipped with this exoskeleton are used to quantify the disturbances induced by the device during locomotion and to show the benefit of passive mechanisms introduced in the mechanical attaches as well. The authors also demonstrated how the device’s transparency can be improved by providing the motor torques in order to compensate the inertial and gravitational effects. This can be done rely on the knowledge of the locomotion movement phases. A robust gait phase detection method was implemented on the experimental device in order to identify specific gait phases in real time. This method exploits the K-nearest neighbors algorithm to identify the k-closest trained vectors, coupling with a discrete time Markov chain to determine the phases shift probability during the gait cycle. This gait detection algorithm was tested with a percentage of success of more than 95% when the subjects walked with constant and variable stride lengths.

Dynamic activity of unloader knee braces in genu varum subjects: New insights to improve compliance in medial knee osteoarthritis patients?

Using unloader knee braces with 3-point pressure in knee osteoarthritis patients is debated. The main reason is discomfort resulting in poor compliance. Studying the external knee adduction moment (EKAM) curve, gold standard in the medial knee load estimation, should be helpful to reduce this discomfort. Reducing constraint solely during the stance phase of gait (combined with an inactivation during large knee flexion) should indeed considerably improve comfort. Thus, the objective of this study was to validate both a method for measuring dynamic activity of new unloader knee braces and to highlight the biomechanical effectiveness of these orthoses. A specific tool incorporated into the brace at the leg interface was developed to quantify knee moments in situ. This tool was beforehand validated in accuracy and retest reliability A kinematic and kinetic analysis was performed on 8 healthy subjects (genu varum) throughout 7 knee valgus braces conditions (and a control condition without orthosis). Each orthosis was endowed of one, two or three mechanisms resulting in all possible combinations (valgus pad and/or cable on the external hinge and/or distraction on the medial hinge). The relative absolute mean bias of the tool was approximatively 4% (accuracy) and the standard error of measurement was close to 1.3% (retest reliability). Femoro-tibial angle in static position, 1st and 2nd EKAM pics, level arm and adduction angle at pics moment as well as maximum knee flexion were significantly reduced by some orthosis ( P < 0.001). The valgus orthosis moment varied significantly at 2nd EKAM pic depending on to the orthosis worn ( P < 0.006). Reported accuracy and retest reliability appear suitable to measure dynamic constraints induced by a knee orthosis. Thereby, biomechanical parameters allow us to point out the benefit of some new unloading knee orthoses, especially the device based on both lateral valgus pad and medial distraction.

脳血管障害片麻痺患者に対するRobotics Knee Orthosisを使用した練習の効果

脳血管障害片麻痺患者に対するRobotics Knee Orthosisを使用した練習の効果

膝装具歩行における制御戦略の解析

膝装具歩行における制御戦略の解析

Knee orthoses for treating patellofemoral pain syndrome.

Knee orthoses for treating patellofemoral pain syndrome.

Design and control of an active knee orthosis driven by a rotary Series Elastic Actuator

Active orthosis is one of the main research topics in the field of motor recovery. This paper deals with the design and control of an active knee orthosis driven by a customized rotary Series Elastic Actuator (SEA). The proposed actuator includes a DC motor, a worm gear and a customized torsion spring. Since the elastic element is the most important component in SEA design, a finite element analysis of the spring is performed to meet the specific requirements for knee assistance. Torque and impedance control are implemented to ensure secure interaction with the patient and to enable new strategies for rehabilitation. The torque controller, cascaded with an inner motor velocity control loop, is based on H∞ criterion to achieve good system performance with relation to parametric uncertainties and external disturbances. The impedance control is implemented using a PD position controller in cascade with the torque controller, where the outer position controller determines the desired torque according to position and velocity errors and impedance parameters. A variable impedance control strategy is then implemented to show the possibility to regulate the impedance of the knee joint during walking. Experiments considering the interaction between the subject and the active orthosis are performed to evaluate the proposed controllers.

A Novel Knee Orthosis in the Treatment of Patellofemoral Pain Syndrome

Context: Patellofemoral Pain (PFPS) accounts for up to 25% of knee injuries in sports medicine clinics, with up to 91% of symptoms unresolved after conservative treatment at 5 years. The variability of response to treatment reflects its multi-factorial biomechanical etiologies. Bracing has been utilized to modify patellofemoral kinematics, generally by increasing patellofemoral contact area. The DJO Reaction orthosis is unique in its shock-absorbing elastomeric design, which is created to dissipate peak stress and enhance patellar tracking. Objective: To assess whether the DJO Reaction Brace reduces pain and improves functional outcomes in patients with chronic PFPS. Design: Cohort Series. Setting: Academic Sports Medicine Clinic. Patients: Twenty-two individuals between 18 and 40 years old with chronic patellofemoral pain have failed conservative treatment. Intervention: DJO Reaction Brace. Main Outcome Measures: Kujala Anterior Knee Pain Scale, Knee Injury and Osteoarthritis Outcome Score. Results: Seven males and 10 females with an age range of 19 - 39 years old complete the study. At an average follow-up time of 55 days, the Kujala score significantly improves by 9.8%, and KOOS Scores increase by the following statistically significant amounts: symptom 3.2%, pain 10.7%, sports and recreation 12.9%, quality of life 20.2%. Conclusion: The DJO Reaction orthosis reduces knee pain, increases function, and enhances quality of life with individuals with PFPS and is effective in the conservative care of patellofemoral pain syndrome.

Focal Myositis in paediatric age

Focal Myositis is a rare pseudotumor of unknown aetiology that is often difficult to diagnose and treat. Typically afflicting people in adulthood, it has occasionally been reported also among children. the aim of this study is to review the literature of Focal Myositis in paediatric age in order to compare the clinical manifestation and the various treatment suggested by different authors. this article describes a 6-year-old boy with focal myositis in gracilis muscle successfully treated by conservative methods, including nocturnal leg traction, intensive physiokinesi therapy and articulated knee orthosis guided to progressive extension. Furthermore a systematic review of literature concerning focal myositis in paediatric age is reported. our case and the review of literature suggests that conservative methods should be the first-choice treatment for FM in paediatric age and that surgery should be strictly reserved for selected cases where non-invasive methods have previously failed.

Design and control of an active ankle–knee orthosis inspired by biarticular musculoskeletal structure of the human lower limb

This paper proposes a novel mechanism for orthotic devices, which has an active joint actuator with a biarticular elastic mechanism that connects two joints simultaneously. The biarticular elasticity in the proposed mechanism is adopted to utilize the energy transfer function of the biarticular muscles so that (1) the torque from the active joint actuator is efficiently transmitted, and (2) the forces required to propel the upper body forward are assisted in a more efficient and sophisticated way. In recent years, many researchers have discovered that the biarticular elasticity is a key mechanism of humans’ efficient movement and implemented the biarticular principle into various types of robots. However, the application of the biarticular mechanism has been hindered by the coupling and redundancy which the mechanism induces. This paper provides theoretic fundamentals for analyzing the kinematics and dynamics of the biarticular elasticity to help engineers design assistive mechanisms and controllers using the biarticular elasticity. The effectiveness of the proposed methods are verified by simulation studies in this paper.

THU0560 Efficiency of Patient Education on Early Stage of Rheumatoid Arthritis

BackgroundPatient education is an important component of the care for patients with rheumatoid arthritis (RA), giving the possibilities for self-management of the disease [1, 2].ObjectivesTo develop the education program for...

THU0559 Comparative Efficiency of Four Rehabilitation Programs for Patients with Early Rheumatoid Arthritis

BackgroundRheumatoid arthritis (RA) requires long term management by drug treatments, rehabilitation techniques and cooperation of the multidisciplinary team [1–3].ObjectivesTo compare the efficacy of four rehabilitation programs for patients with early...

The effect of migration of instantaneous centre of knee orthosis rotation during gait - in vivo displacement measurements in two experimental variants.

The knee joint is a bicondylar hinge two-level joint with six degrees of freedom. The location of the functional axis of flexion-extension motion is still a subject of research and discussions. During the swing phase, the femoral condyles do not have direct contact with the tibial articular surfaces and the intra-articular space narrows with increasing weight bearing. The geometry of knee movements is determined by the shape of articular surfaces. A digital recording of the gait of a healthy volunteer was analysed. In the first experimental variant, the subject was wearing a knee orthosis controlling flexion and extension with a hinge-type single-axis joint. In the second variant, the examination involved a hinge-type double-axis orthosis. Statistical analysis involved mathematically calculated values of displacement P. Scatter graphs with a fourth-order polynomial trend line with a confidence interval of 0.95 due to noise were prepared for each experimental variant. In Variant 1, the average displacement was 15.1 mm, the number of tests was 43, standard deviation was 8.761, and the confidence interval was 2.2. The maximum value of displacement was 30.9 mm and the minimum value was 0.7 mm. In Variant 2, the average displacement was 13.4 mm, the number of tests was 44, standard deviation was 7.275, and the confidence interval was 1.8. The maximum value of displacement was 30.2 mm and the minimum value was 3.4 mm. An analysis of moving averages for both experimental variants revealed that displacement trends for both types of orthosis were compatible from the mid-stance to the mid-swing phase. 1. The method employed in the experiment allows for determining the alignment between the axis of the knee joint and that of shin and thigh orthoses. 2. Migration of the single and double-axis orthoses during the gait cycle exceeded 3 cm. 3. During weight bearing, the double-axis orthosis was positioned more correctly. 4. The study results may be helpful in designing new hinge-type knee joints.

Does Robot-Assisted Gait Rehabilitation Improve Balance in Stroke Patients? A Systematic Review

The aim of this systematic review was to summarize the improvements in balance after robot-assisted gait training (RAGT) in stroke patients. Two databases were searched: PubMed and Web of Knowledge. The most important key words are “stroke,” “RAGT,” “balance,” “Lokomat,” and “gait trainer.” Studies were included if stroke patients were involved in RAGT protocols, and balance was determined as an outcome measurement. The articles were checked for methodological quality by 2 reviewers (Cohen’s κ = 0.72). Nine studies were included (7 true experimental and 2 pre-experimental studies; methodological quality score, 56%-81%). In total, 229 subacute or chronic stroke patients (70.5% male) were involved in RAGT (3 to 5 times per week, 3 to 10 weeks, 12 to 25 sessions). In 5 studies, the gait trainer was used; in 2, the Lokomat was used; in 1 study, a single-joint wearable knee orthosis was used; and in 1 study, the AutoAmbulator was used. Eight studies compared RAGT with other gait rehabilitation methods. Significant improvements (no to large effect sizes, Cohen’s d = 0.01 to 3.01) in balance scores measured with the Berg Balance Scale, the Tinetti test, postural sway tests, and the Timed Up and Go test were found after RAGT. No significant differences in balance between the intervention and control groups were reported. RAGT can lead to improvements in balance in stroke patients; however, it is not clear whether the improvements are greater compared with those associated with other gait rehabilitation methods. Because a limited number of studies are available, more specific research (eg, randomized controlled trials with larger, specific populations) is necessary to draw stronger conclusions.