Comparison between Weight Activated and Polycentric Knee Joints on the Gait Performance of Transfemoral Amputees

Amputation of the lower limb results is a physical change in the body physiology that is often associated with functional limitations, such as an impaired ability to transfer, balance, and/or ambulation. A prosthetic limb acts as a replacing device which helps to restore some of the physical and biomechanical features of the lost foot, ankle, shin, and knee. Prosthetic knee joints have a dual function to perform: to provide stability during the stance phase and to provide controlled motion during the swing phase. Prosthetic knee joint designs have become extremely sophisticated as compared to early constant friction single axis mechanisms. Prosthetists around the world today are spoilt for choice regarding the choice of prosthetic knee joints for their patients. Unfortunately, little quantitative data is available comparing the performance of different types of prosthetic knee joints and prosthetic prescription is often based on clinical knowledge and experience, rather than objective comparison of prosthetic designs. Stance phase stability and swing phase response are both important aspects to consider. The aim of this study was to compare the gait of persons with trans-femoral amputation using two different knee joints by means of a questionnaire, gait analysis measuring temporo-spatial variables and measurement of energy expenditure during walking and to find a relationship among the variables studied.It was found that the polycentric knee joint provides a balance between stability and mobility thereby providing a smooth transition from the stance to the swing phase.