Comparative study between patellar-tendon-bearing and pressure cast prosthetic sockets.

This study compared the pressure distribution at the residual limb and socket interface in amputees wearing a pressure cast (PCast) socket system with amputees wearing the patellar-tendon-bearing (PTB) socket. The PCast system requires the subject to place his or her residual limb in a pressure chamber. Pressure is applied to the residual limb while the subject adopts a normal standing position. Four unilateral male amputees were fitted with both PTB and PCast sockets. Using a specially built strain-gauge-type pressure transducer, we recorded residual limb and socket pressure profiles for each subject wearing the two types of sockets during standing and walking. While some subjects exhibited similar anterior-posterior or medial-lateral pressure profiles for both prostheses, especially during push-off, other subjects exhibited high pressure distally in the PCast socket or higher-pressure concentration at the proximal region in the PTB socket.