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The aim of this study was to determine changes in knee biomechanics during badminton lunges due to fatigue, lunge strategy and knee bracing. Kinetic and kinematic data were collected from 16 experienced right-handed badminton players. Three factor repeated measures ANOVAs (lunge direction—fatigue—brace) were performed with Least Significant Difference pairwise comparisons. In addition, clinical assessments including; Y-balance test, one leg hop distance and ankle dorsiflexion range of motion were performed pre- and postfatigue. The knee showed significantly greater flexion during the forehand lunge compared to backhand. In contrast, the internal rotation velocity and the knee extension moment were greater during backhand. Knee angular velocity in the sagittal plane, peak knee moment and range of moment in the coronal plane and stance time showed significantly lower values postfatigue. In addition, the peak knee adduction moment showed significantly lower values in the braced condition in both the fatigued and nonfatigues states, and no significant differences were seen for peak vertical force, loading rate, approach velocity, or in any of the clinical assessment scores. There appears to be greater risk factors when performing a backhand lunge to the net compared to a forehand lunge, and proprioceptive bracing appears to reduce the loading at the knee. Universidad Católica de Valencia San Vicente Mártir Generalitat Valenciana Ciencias de la Actividad Física y del Deporte Instituto Universitario de Ciencias de la Actividad Física y del Deporte

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.

International audience; The knee is the largest joint in the body and supports high loads, up to several times the body weight. It is vulnerable to injury during sport or professional activities, potentially leading to chronic knee instability. This instability is a functional issue to the patient and is characterized by a “wobbly” feeling. Different internal structures take part in joint stabilization by passive (ligaments, capsule) or active (neuro-muscular system and proprioception) action. The most common injury involves the anterior cruciate ligament (ACL) complete or partial rupture: it is involved in 24% of all knee injuries and 59% of ligamentous injuries [1]. In the United States,the annual incidence in the general population is approximately 1 in 3500 with 100,000 ACL reconstructions performed each year [2, 3]. These conditions are a huge burden on individualsand healthcare systems. Diagnosis of knee instability involves a discussion with the patient and a clinical examination, usually the Lachman test. It consists in a manual anterior translation of the tibia aiming at putting the ACL in tension. By practice, the examiner is able to grade the laxity by severity [4]. However, its sensitivity and specificity to detect complete ACL ruptures depends on the experience of the examiner, the patient’s body type and the delay between the accident and examination [5]. In order to reduce this variability, arthrometers were developed.These devices apply an increasing force to induce a postero-anterior drawer and measure the corresponding translation. Displacement-load curves of the healthy and injured knees are compared; ACL rupture is ascertained when differential laxity is higher than a certain threshold. Well-known arthrometer devices are the KT-1000 developed by [6] and the GNRB® [7]. The former is very popular and has been widely studied; its sensitivity to detect complete ACL ruptures is 77% and its specificity 90% (threshold: differential laxity of 3 mm at 130 N). Thelatter was developed recently; two studies [5, 7] highlighted the superiority of this device compared to similar apparatus. A differential threshold of 3 mm at 134 N is used to determine complete rupture: its sensitivity is 70% and specificity 99%. This arthrometer device is also used to diagnose partial ruptures (threshold of 1.5 mm at 134 N) with a sensitivity of 80% and a specificity of 87%.Knee braces or orthoses are usually part of the standard therapy for knee instability and are commonly prescribed by physicians and medical practitioners. Their claimed mechanical effects are to support/align the joint and increase proprioceptive input [8]. However, very few studies actually show significant actions, from biomechanical studies to therapeutic trials [9, 10]. Mechanical/ physiological effects have been emphasized, but the mechanisms of action have been poorly characterized [8, 9, 10, 11, 12, 13]. What is more, subjective evaluations of patients highlight a large demand for these products; therefore, their efficiency is still widely discussed among medical experts. In particular, therelative importance of the two principal stabilizing mechanisms is not known:- joint stiffening by adding supporting structures, e.g. hinged bars secured to the joint by straps and fabric (passive mechanism)- neuromuscular control enhancement by proprioceptive effect (active mechanism)As a consequence of these uncertainties, medical practitioners and manufacturers still lack a simple evaluation tool for knee orthoses. A French committee of experts highlighted this problem [14] and stated that orthoses must be evaluated by taking both the mechanisms of action and the desired therapeutic effects into account.Although the passive action of knee braces to prevent a drawer motion has already been characterized on surrogate limbs [15, 16, 17], only one attempt has been made to link these measures to corresponding expected in-vivo actions through numerical modelling [18, 19], highlighting a passive stiffening much lower than what is brought by intact ligaments. However, a real clinical study is still needed to validate the numerical results and investigate the influence of patient-specific factors such as morphology, injury severity, neuromuscular adaptation and instability feeling control.This study is aimed at objectively quantifying the joint stiffening action of various commercial braces in-vivo using a GNRB® arthrometer on a number of pathological patients.

This research analyzed the effect of bilateral hinged knee braces on a healthy knee from a biomechanical frame in vivo. This was accomplished by fitting a knee brace with two customized wireless force/torque (F/T) sensors that could readily record force and torque during live motion, while the kinetics at the knee were computed using the inverse dynamics of the motion capture and force plate data. Four tasks to test the brace’s effects were drop vertical jumping, pivoting, stop vertical jumping, and cutting. The results showed that the hinges in the knee brace can absorb up to 18% of the force and 2.7 % of the torque at the knee during various athletic motions. Thus, the hinges demonstrated minimal effect in reducing the mechanical load on the knee. There were limitations concerning the consistency of the motions performed by the subjects during the trials and the influence of the other portions of the brace to evaluate the overall effectiveness of the brace as a whole. Future works may incorporate a fatigue protocol and injured subjects to better determine the effects of the brace. There is still a need for more research on the biomechanical influence of knee braces to develop safer and more effective products.

Introduction Conflicting evidence exists regarding the effects of knee orthoses on proprioception. One belief is that pressure applied by orthoses heightens kinesthetic awareness and that this affects balance. This study aimed to investigate the effects of two different orthosis designs on kinesthetic awareness and balance in healthy individuals. Methods Twenty individuals (13 women) participated in this case series study. Each was tested wearing 1/no orthosis, 2/soft elastic orthosis and 3/non-elastic jointed orthosis. Pressure under orthoses was recorded. Kinesthetic awareness was investigated by testing joint position sense and threshold to detection of passive motion. Balance was tested using a modified sensory organization test. Results Non-elastic jointed orthoses applied the greatest pressure to the knee. With non-elastic jointed orthoses, threshold to detection of passive motion was significantly poorer for pooled results ( p = 0.02) and when the start position of the knee was 70° (mean threshold = 0.6°, 0.6°, 0.7° for no-orthosis, elastic and jointed-orthoses; p = 0.03). No major differences were observed in JPS or balance and correlation between proprioception and balance was poor. Conclusions There may be a limit to the amount of pressure that should be applied to the knee joint by an orthosis. Exceeding this limit may compromise kinesthetic awareness.

The aim of this study was to investigate the effects of the useof a knee brace on 15 subjects with hypertonic hemiparesis. The middlecerebral artery was involved in all subjects. The Ashworth scale was usedto screen for the presence of spasticity in the quadriceps muscles.Measurements of gait speed, step and stride length were taken in the middle 10 metres of a 15 metre paper walkway. A comparison of these gait parameters without and with the use of a knee brace was made. A ques-tionnaire was also used to evaluate how subjects responded to the use of aknee brace.The results showed that the mean speed for all 15 subjects increased withthe use of a brace, (p = 0.05). Step and stride length without and with the use of a brace showed no statistical differences.It was therefore concluded that the FECK brace appears to have an effect on the walking speed of subjects withhypertonic hemiparesis

Twenty Virginia Tech varsity football players, age 18-24, volunteered as subjects to examine the effects of wearing prophylatic knee sleeves/ braces on selected isokinetic measures (i.e. strength, power and endurance). Each subject performed the Biodex (Multi-Joint System 2AP) knee extension test in each of three experimental conditions: sleeved with the Don Joy Knee support (S-DJ); braced with the McDavid lateral knee support (B-MD); and the control, unsupported condition (C-UN). The order of experimental conditions and the specific knee tested were randomized. The subjects were administered a Biodex knee extension test at 60 deg/sec, 210 deg/sec, and 450 deg/sec. The test protocol consisted of five maximal repetitions at 60 deg/sec, twenty maximal repetitions at 210 deg/sec and thirty maximal repetitions at 450 deg/sec. The following isokinetic measures were recorded: (1) peak torque to body weight ratio at 60 deg/sec. (2) work to fatigue ratio at 210º and 450 deg/sec. (3) average power at 210º and 450 deg/sec, and (4) range of motion at 60º, 210º, and 450 deg/sec. One way repeated measures analysis of variance revealed significant difference ( p > .03 ) in peak torque to body weight ratio treatment groups; work to fatique ratio, average power and range of motion revealed no significant diference among the three experimental conditions. The investigator concluded that prophylatic knee sleeves/braces effects peak torque to body weight ratio; the effect of different levels of condition does not depend on what level of speed is present for work to fatigue, average power and range of motion. Master of Science

Accurate and specific predictive numerical simulation of the human gait can help in many clinical routines. Predictive methods often track modifications applied to a reference motion but that usually do not take into account the characteristics and the stability of the predicted motion. We propose an approach that includes a cost function, computed on the predicted motion, which optimization preserves these concerns. Experimental studies on subjects with different walking patterns confirmed that our method preserves the characteristics of the gait.