Twiste, M, Nester, CJ and Kenney, LPJ 2006, 'Does transverse plane mechanical compliance affect amputee gait and in-socket forces?' , Journal of Biomechanics, 39 (S1) , p. 171.
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Transverse plane rotation in an amputee's residual-limb appears to be less than in non-amputees [1,2]. However, it remains unclear firstly, to what extent this is driven by the properties of the prosthesis, and secondly, whether this has detrimental effects on the residual-limb. In trans-tibial prostheses, the socket and foot are commonly connected via a rigid adapter, which restricts the residual-limb's transverse rotation while inside the socket and can increase the forces exerted onto the residual-limb. This can subsequently trigger tissue damage. Instead of a rigid connection, an adapter with a compliant element can be fitted to prostheses to allow some transverse rotation. This novel study quantified in-socket forces and amputated side kinetics and kinematics to investigate the mechanisms by which the adapter reduces in-socket forces. Gait tests were conducted with ten unilateral trans-tibial amputees who walked on a prosthesis that had an adapter with (A) and without (B) a compliant element. Comparing (A) with (B) showed that, at early stance, whilst the socket rotated internally due to adapter compliance, the pelvis was therefore likely to internally rotate and move forward more relative to the prosthesis. This forward motion is associated with greater elevation of the centre of mass, which can be compensated for by increasing and delaying the peak in knee flexion during stance. Peak knee flexion magnitude was not significantly increased with the adapter (approximately 0.6 °, p = 0.976). However, peak knee flexion was significantly delayed with the adapter (approximately 3.28% of stance, p=0.010). Knee flexion is a common shock absorption mechanism, which significantly reduced the peak vertical ground reaction force (approximately 0.2N/kg, p=0.050) and delayed it, although not significantly (approximately 1.41% of stance, p=0.141), thus overall reducing the vertical loading rate. Reduced in-socket forces supported these findings. In conclusion, adapter compliance has therefore beneficial effects on residual-limb forces.
|Themes:||Subjects / Themes > R Medicine > R Medicine (General)
Health and Wellbeing
|Schools:||Schools > School of Health Sciences > Centre for Health Sciences Research
Schools > School of Health Sciences
|Journal or Publication Title:||Journal of Biomechanics|
|Depositing User:||M Twiste|
|Date Deposited:||21 Dec 2010 14:04|
|Last Modified:||30 Nov 2015 23:49|
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