Clinical management of ankle injuries often involves use of braces to provide pain relief and stability. Individuals with braced ankles may be at more risk of injury while turning. The aim of this study was to evaluate the biomechanical effects of one of the commonly prescribed pneumatic ankle braces on gait parameters while turning. Three-dimensional gait data was collected using a 7 camera, VICON 612 (Oxford Metric, UK) motion analysis system (120 HZ) synchronised with a single Kistler force plate embedded in the floor and set at a sampling frequency of 600HZ. Sixteen retro-reflective markers were attached to anatomical landmarks on both lower limbs and pelvis using wig tape. In the case of the braced ankle, markers were attached on the brace over the respective body landmarks. Out of ten trials, five were performed with and the other five without brace. Comparative results were produced between braced and un-braced ankle during turning at 90 degrees with the right foot landing on the force plate and turning right. Results show that use of brace is effective in reducing gross moments about the ankle joint even at the time of turning but it does not totally eliminate motion. Both conditions showed different rotation moments at knee but hip rotation moments were not affected by the brace. Knee rotation moment without brace was mainly in internal rotation (0.301Nm/kg) towards the terminal stance phase and it reduced to 0.128Nm/kg by bracing the ankle. A new type of turning strategy was identified where the subject pre-planned the turn in late swing phase before landing on the ground probably to avoid a fall. It is important that patients with ankle injuries receive supervised gait training to improve their turning confidence during their rehabilitation therapy.
This study was aimed to develop a non-invasive technique to analyse motion of the patella during the gait cycle. Ten subjects with no history of patello-femoral pain syndrome or evidence of patella mal-tracking on clinical examination were individually assessed on 160 dynamic walking trials. Retro-reflective markers were attached to the proximal, distal, medial and lateral poles of the patella and the position of the patella relative to the centre of the knee joint was tracked and recorded during their gait cycle using a nine camera (120Hz) ViconTM infra-red motion analysis system. We found that there was more medial-lateral motion (shift) of the patella than proximal-distal (tilt) motion during the gait cycle. It was noted that the patellar shift motion occurred in the swing phase or the early stance phase of the gait cycle of all subjects with the maximum patellar shift occurring when the knee was flexed between 30–56 degrees in the majority of subjects. Similarly the patellar tilt motion occurred in the swing phase or the early stance phase of the gait cycle with the maximum patellar tilt occurring between 20–36 degrees of knee flexion in the majority of subjects. These results indicate that normally the maximum amount of patellar shift and tilt occurs in the swing and early stance phases of the gait cycle and that abnormal patellar motion can be detected if excessive shift or tilt occurs outside of these phases. From the findings of the current study, it is proposed that future studies are needed to quantify patellar motion during walking. The future work should be directed to assess patellar motion during swing phase and early stance phase of the gait cycle using more sophisticated techniques like dynamic magnetic resonance imaging to exactly quantify patellar motion.
It was found that there was more medial-lateral motion (shift) of the patella than proximal-distal (tilt) motion during the gait cycle. It was noted that the patella shift motion occurred in the swing phase or the early stance phase of the gait cycle of all subjects with the maximum patella shift occurring when the knee was flexed between 30–56 degrees in the majority of subjects. Similarly the patellar tilt motion occurred in the swing phase or the early stance phase of the gait cycle with the maximum patella tilt occurring between 20–36 degrees of knee flexion in the majority of subjects.
