Trunk lean and toe out gait strategies impact on lower limb joints.

Gait retraining as a non-invasive prospective approach to restore mechanical loading at the knee joint and slowing down knee osteoarthritis (OA) progression shows great promise. However, the impact of gait modifications such as an increase in foot progression angle (FPA) or lateral trunk lean (LTL) on the ankle and hip is not yet well understood. Thus, the goal of this study is to provide insight on the impact of FPA and LTL on the sagittal and frontal external moments at the ankle and hip of healthy participants. We hypothesize that there is an optimum, for which an increase in FPA and/or LTL minimize the knee adduction moment (KAM) without increasing significantly the frontal and sagittal external moments at the ankle and hip during gait. To test this hypothesis, 23 participants performed walking trials with modified FPA and/or LTL angles following a real-time visual feedback. The hypothesis was not confirmed and while not all the gait modifications performed by the participants in this study reduced the KAM, they significantly increased the sagittal moment at the ankle and the frontal moment at the hip. This study highlights the importance to consider the biomechanical consequences of gait modifications on the ankle and hip before considering a clinical application of gait retraining approaches.

Associations between gait and clinical parameters in patients with severe knee osteoarthritis: a multiple correspondence analysis.

BACKGROUND: Given the complexity of the gait of patients with knee osteoarthritis, a multiple correspondence analysis may be helpful to optimise the extraction of relevant gait and clinical information. Therefore, the aims of this study are to identify the main associations with clinical and gait biomechanical parameters and to evaluate whether there are more specific knee osteoarthritis groups with different gait profiles. METHODS: Ninety patients with severe knee osteoarthritis and twenty-six healthy individuals participated in this study. Pain and function were assessed with the WOMAC Index; knee joint deformity was assessed by the hip-knee-ankle angle on full-limb radiography; and full body gait analysis was performed with a motion analysis system and force plates. FINDINGS: Using multiple correspondence analysis, two categories of gait parameters that best explain the gait variance of patients with knee osteoarthritis were highlighted. The forward displacement category is composed of the parameters speed, stride length, hip flexion and knee flexion. The frontal category is composed of the parameters thorax obliquity and knee adductor moments. Moreover, based on these parameters, four distinct gait profiles were identified: two gait profiles were associated with knee varus deformities, increased thorax obliquity and different forward displacements, while two gait profiles were associated with valgus deformities and different forward displacements. INTERPRETATION: These gait parameters can be used to simplify the characterisation of the gait of the knee osteoarthritis population. Patients in varus profiles increase thorax obliquity on the stance limb and may reduce forward displacement. Patients in valgus profiles, however, only reduce forward displacement.

Full body gait analysis may improve diagnostic discrimination between hereditary spastic paraplegia and spastic diplegia: a preliminary study.

Hereditary spastic paraplegia (HSP) and spastic diplegia (SD) patients share a strong clinical resemblance. Thus, HSP patients are frequently misdiagnosed with a mild form of SD. Clinical gait analysis (CGA) has been highlighted as a possible tool to support the differential diagnosis of HSP and SD. Previous analysis has focused on the lower-body but not the upper-body, where numerous compensations during walking occur. The aim of this study was to compare the full-body movements of HSP and SD groups and, in particular, the movement of the upper limbs. Ten HSP and 12 SD patients were evaluated through a CGA (VICON 460 and Mx3+; ViconPeak(®), Oxford, UK) between 2008 and 2012. The kinematic parameters were computed using the ViconPeak(®) software (Plug-In-Gait). In addition, the mean amplitude of normalised (by the patient's height) arm swing was calculated. All patients were asked to walk at a self-selected speed along a 10-m walkway. The mean kinematic parameters for the two populations were analysed with Mann-Whitney comparison tests, with a significant P-value set at 0.05. The results demonstrated that HSP patients used more spine movement to compensate for lower limb movement alterations, whereas SD patients used their arms for compensation. SD patients had increased shoulder movements in the sagittal plane (Flexion/extension angle) and frontal plane (elevation angle) compared to HSP patients. These arm postures are similar to the description of the guard position that toddlers exhibit during the first weeks of walking. To increase speed, SD patients have larger arm swings in the sagittal, frontal and transversal planes. Upper-body kinematics, and more specifically arm movements and spine movements, may support the differential diagnosis of HSP and SD.

Evaluation of unipodal stance in knee osteoarthritis patients using knee accelerations and center of pressure.

OBJECTIVE: This study aims to compare knee joint instability and postural impairments during the performance of a unipodal stance task between patients having knee osteoarthritis (OA) and healthy elderly subjects using knee accelerations and center of pressure (COP) measurements. MATERIALS AND METHODS: Twenty patients with medial knee OA and nine healthy individuals participated in this study. Three-dimensional (3D) knee joint accelerations and COP were measured during unipodal stance. The range and the root mean square (RMS) were extracted from medial lateral (ML) and anterior-posterior (AP) knee accelerations, whereas sway area, velocity, and ML and AP ranges were measured from the COP. The average parameters of three trials for each subject were compared between groups. RESULTS: Results show that knee OA patients exhibited a significantly higher range of knee acceleration in both ML (0.22±0.08 g vs 0.15±0.05 g) and AP (0.17±0.06 g vs 0.06±0.01 g) directions and a lower COP velocity (136.6±22.3 mm/s vs 157.6±18.4 mm/s) than did the healthy age-matched group. Significant correlations between the COP and knee acceleration parameters were also obtained. CONCLUSIONS: This study confirmed that patients with knee OA displayed greater body sway than did able-bodied subjects. Moreover, using an accelerometric-based method, this study highlighted the higher knee joint instability in the frontal and sagittal planes in knee OA patients compared with able-bodied subjects during a unipodal standing task.

Investigation of standing balance in diabetic patients with and without peripheral neuropathy using accelerometers.

BACKGROUND: Peripheral neuropathy is recognised to be the most symptomatic complication of diabetes and is also linked to postural instability. This study investigates balance instability in diabetic patients with and without peripheral neuropathy. METHODS: Quiet standing balance was investigated using an accelerometric-based method in 24 diabetic patients (12 with and 12 without peripheral neuropathy) and compared with 12 control subjects. Accelerations were measured at lumbar and ankle levels using three accelerometers. Two standing conditions of 30s were evaluated (i.e., eyes opened, eyes closed). The range and root mean square values were calculated on the anterior posterior component of lumbar and ankle accelerations and for the medial lateral component of lumbar accelerations. Differences between parameters were compared between groups using ANOVA and post hoc comparisons. FINDINGS: The diabetic patients with peripheral neuropathy show higher-range and root mean square values compared with those of control subjects and diabetic patients without peripheral neuropathy. Significant differences between groups have been detected for anterior posterior range of lumbar acceleration, which was significantly higher for diabetic patients with peripheral neuropathy, compared with those of others groups. Significant higher values for diabetic patients with peripheral neuropathy were also detected for anterior posterior range and root mean square of ankle accelerations compared with control subjects. Visual deprivation shows an increase in accelerometric parameters for each group. INTERPRETATION: This study is the first to investigate the balance instability of diabetic patients using accelerometers. Results confirm that diabetic patients with peripheral neuropathy have greater postural instability with higher acceleration values than those of control group and diabetic patients without peripheral neuropathy.

The responsiveness of three-dimensional knee accelerations used as an estimation of knee instability and loading transmission during gait in osteoarthritis patient's follow-up.

OBJECTIVE: Knee instability and joint loading transmission are two important biomechanical factors in subjects with knee osteoarthritis (OA). However, the relationship between these factors in a rehabilitation treatment remains unclear. The purpose of this study is to determine the responsiveness of a new three-dimensional (3D) acceleration method used as an estimation of knee instability and joint loading transmission during gait in OA subjects after a rehabilitation treatment. METHOD: Twenty-four subjects with medial knee OA were included in this study. They had clinical and gait evaluations before and after 12 weeks of treatment. 3D linear knee accelerations, quadriceps and hamstring isometric strength and Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) pain were quantified, and compared between both evaluations. Nine asymptomatic subjects participated in this study for gait comparison. RESULTS: A significant reduction of the anterior posterior (AP) knee acceleration peak (P=0.02) had been detected after the treatment. No difference for both distal and lateral knee accelerations peak was found. A significant increase in quadriceps (P<0.001) and hamstring (P=0.006) strength was seen after treatment. The WOMAC of pain had shown significant reduction after the treatment (P<0.001). CONCLUSION: The present study demonstrates that the estimation of knee acceleration parameters is sensitive to changes in knee OA gait after a rehabilitation treatment. This study also indicates that a treatment of 3 months which combines therapeutic and exercises program could have benefits on knee OA by increasing AP knee stability and stabilize joint loading transmission during gait.

Estimation of tibial and femoral 3D linear accelerations during gait.

Shock wave traveling through the skeletal are more and more considered in the development of articular disorders. A method to quantify those skeletal transients is to estimate body segment linear accelerations. However, linear accelerations magnitude is influenced by many factors such as location and fixation of sensors, walking velocity, walking level and also by wearing conditions. Hence, experimental results in literature can't be easily compared and normative data haven't been established yet. The present paper proposes a method to estimate three-dimensional (3D) tibial and femoral linear accelerations during treadmill walking. 15 able-bodied subjects were evaluated. 3D kinematics data recorded from an optoelectronic system (Optotrak 3010, Northern Digital, Canada) at knee joint level were derived to estimated 3D linear accelerations of the tibia and the femur at their respective coordinate system origins.