Toe clearance when walking in people with unilateral transtibial amputation: Effects of passive hydraulic ankle

YesMost clinically available prosthetic feet have a rigid attachment or incorporate an “ankle” device allowing elastic articulation during stance, with the foot returning to a “neutral” position at toe-off. We investigated whether using a foot with a hydraulically controlled articulating ankle that allows the foot to be relatively dorsiflexed at toe-off and throughout swing would increase minimum toe clearance (MTC). Twenty-one people with unilateral transtibial amputation completed overground walking trials using their habitual prosthetic foot with rigid or elastic articulating attachment and a foot with a hydraulic ankle attachment (hyA-F). MTC and other kinematic variables were assessed across multiple trials. When using the hyA-F, mean MTC increased on both limbs (p= 0.03). On the prosthetic limb this was partly due to the device being in its fully dorsiflexed position at toe-off, which reduced the “toes down” foot angle throughout swing (p = 0.01). Walking speed also increased when using the hyA-F (p = 0.001) and was associated with greater swing-limb hip flexion on the prosthetic side (p = 0.04), which may have contributed to the increase in mean MTC. Variability in MTC increased on the prosthetic side when using the hyA-F (p = 0.03), but this did not increase risk of tripping

Investigation of the biomechanical effect of variable stiffness shoe on external knee adduction moment in various dynamic exercises

10.1186/1757-1146-6-39Journal of Foot and Ankle Research61

The relationship between external knee moments and muscle co-activation in subjects with medial knee osteoarthritis

Purpose: External knee moments are reliable to measure knee load but it does not take into account muscle activity. Considering that muscle co-activation increases compressive forces at the knee joint, identifying relationships between muscle co-activations and knee joint load would complement the investigation of the knee loading in subjects with knee osteoarthritis. The purpose of this study was to identify relationships between muscle coactivation and external knee moments during walking in subjects with medial knee osteoarthritis. Methods: 19 controls (11 males, aged 56.6 ±5, and BMI 25.2 ± 3.3) and 25 subjects with medial knee osteoarthritis (12 males, aged 57.3 ± 5.3, and BMI 28.2 ± 4) were included in this study. Knee adduction and flexion moments, and co-activation (ratios and sums of quadriceps, hamstring, and gastrocnemius) were assessed during walking and compared between groups. The relationship between knee moments and co-activation was investigated in both groups. Findings: subjects with knee osteoarthritis presented a moderate and strong correlation between co-activation (ratios and sums) and knee moments. Interpretation: Muscle co-activation should be used to measure the contribution of quadriceps, hamstring, and gastrocnemius on knee loading. This information would cooperate to develop a more comprehensive approach of knee loading in this population

Heterogeneity of tibial plateau cartilage in response to a physiological compressive strain rate

Knowledge of the extent to which tibial plateau cartilage displays non‐uniform mechanical topography under physiologically relevant loading conditions is critical to evaluating the role of biomechanics in knee osteoarthritis. Cartilage explants from 21 tibial plateau sites of eight non‐osteoarthritic female cadaveric knees (age: 41–54; BMI: 14–20) were tested in unconfined compression at 100% strain/s. The elastic tangent modulus at 10% strain ( E 10% ) was calculated for each site and averaged over four geographic regions: not covered by meniscus (I); covered by meniscus—anterior (II); covered by meniscus—exterior (III); and covered by meniscus—posterior (IV). A repeated‐measures mixed model analysis of variance was used to test for effects of plateau, region, and their interaction on E 10% . Effect sizes were calculated for each region pair. E 10% was significantly different ( p  < 0.05) for all regional comparisons, except I–II and III–IV. The regional pattern of variation was consistent across individuals. Moderate to strong effect sizes were evident for regional comparisons other than I–II on the lateral side and III–IV on both sides. Healthy tibial cartilage exhibits significant mechanical heterogeneity that manifests in a common regional pattern across individuals. These findings provide a foundation for evaluating the biomechanical mechanisms of knee osteoarthritis. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 370–375, 2013Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96249/1/22226_ftp.pd

The beneficial effect of hydroxyapatite lasts: A randomized radiostereometric trial comparing hydroxyapatite-coated, uncoated, and cemented tibial components for up to 16 years

Analysis and Stochastic

Contributions of Muscles and External Forces to Medial Knee Load Reduction Due to Osteoarthritis Braces

Background Braces for medial knee osteoarthritis can reduce medial joint loads through a combination of three mechanisms: application of an external brace abduction moment, alteration of gait dynamics, and reduced activation of antagonistic muscles. Although the effect of knee bracing has been reported independently for each of these parameters, no previous study has quantified their relative contributions to reducing medial knee loads. Methods In this study, we used a detailed musculoskeletal model to investigate immediate changes in medial and lateral loads caused by two different knee braces: OA Assist and OA Adjuster 3 (DJO Global). Seventeen osteoarthritis subjects and eighteen healthy controls performed overground gait trials in unbraced and braced conditions. Results Across all subjects, bracing reduced medial loads by 0.1 to 0.3 times bodyweight (BW), or roughly 10%, and increased lateral loads by 0.03 to 0.2 BW. Changes in gait kinematics due to bracing were subtle, and had little effect on medial and lateral joint loads. The knee adduction moment was unaltered unless the brace moment was included in its computation. Only one muscle, biceps femoris, showed a significant change in EMG with bracing, but this did not contribute to altered peak medial contact loads. Conclusions Knee braces reduced medial tibiofemoral loads primarily by applying a direct, and substantial, abduction moment to each subject's knee. To further enhance brace effectiveness, future brace designs should seek to enhance the magnitude of this unloader moment, and possibly exploit additional kinematic or neuromuscular gait modifications

Características da marcha de um paciente com osteoartrose de quadril com e sem auxílio de bengala

O objetivo deste estudo foi comparar características espaciais, temporais e espaço-temporais da marcha de um paciente com osteoartrose de quadril com e sem o auxílio de dispositivo (bengala). O caso é o de um sujeito com osteoartrose de quadril esquerdo de 63 anos, 97,8 kg e 1,76 m. Um sistema de reconstrução tridimensional de movimento foi utilizado para análise da marcha. Foram registrados três ciclos completos da marcha com e sem a utilização da bengala, sendo analisadas variáveis espaciais, temporais e espaço-temporais. Foi feita análise estatística, com nível de significância de 5%. Os principais resultados indicam que o comprimento de passo direito (CPD) e esquerdo (CPE), bem como o comprimento total do ciclo, foram superiores com o uso da bengala durante a marcha; o CPE foi significativamente maior do que o CPD quando o sujeito utilizava a bengala; todas as variáveis temporais foram estatisticamente menores com o uso da bengala; a cadência da marcha e a velocidade foram estatisticamente superiores com a bengala. Pode-se concluir que o uso da bengala gerou diferenças significativas no comportamento das variáveis espaciais, temporais e espaço-temporais durante a marcha, melhorando de forma significativa a eficiência do movimento do paciente com osteoatrose de quadril.The purpose of this study was to compare cane-assisted and non-assisted gait temporal, spatial and spatiotemporal features in a patient with hip osteoarthrosis. The patient studied, with left hip osteoarthrosis, was 63 years old and had 97.8 kg and 1.76 m. A three-dimensional analysis system was used for the analysis of gait. Three complete gait cycles with and without cane assistance were recorded, where temporal, spatial and spatiotemporal variables were analysed. Descriptive statistics was used with the level of significance set at 5%. Main results show that left step length (LSL), right step length (RSL) and stride length were greater during cane-assisted gait; LSL was significantly longer than RSL when the patient used the cane; all temporal variables were statistically lesser in cane-assisted gait; and cadence and walking speed were statistically higher during cane-assisted gait. It may thus be said that use of the cane by the patient with hip osteoarthrosis caused significant differences in spatial, temporal and spatiotemporal variables during gait and significantly improved efficiency of the movement