Comparison of the Piston Movement between two Supracondylar PTB Prostheses in Transtibial Amputees; A Case Report Study

Below the knee amputation is the most common of lower limb amputations. The suspension system of the below the knee prostheses، is an important component of it. The aim of this study was to compare the piston movement of two types of prostheses including «conventional supracondylar PTB» and «supracondylar PTB with pneumatic suspension» in the unilateral below the knee amputee. Patient & This simple quasi-experimental study was done in the Rehabilitation Clinic of Orthotics and Prosthetics Department of Iran Rehabilitation Sciences School، inviting the unilateral below the knee amputee in 2014. After air-cushion designing and manufacturing process، the piston movement of a conventional supracondylar PTB prostheses and supracondylar PTB prosthesis with pneumatic suspension was measured using imaging and markers in 4-step constant loading test including full weight bearing، semi-weight bearing، non-weight bearing and the 30N loading. The mean vertical movement of the markers in conventional prostheses in non-weight bearing was ±15mm، whereas this value ​​decreased in the pneumatic prostheses (5±mm). The mean vertical movement of the markers following 3kg loading in the conventional prostheses was 20±mm while it decreased in the pneumatic prostheses (10±mm). Piston movement decreased using the supracondylar PTB prostheses with pneumatic suspension.