Roentgenological Study of Movements of the Amputation Stump Within the Prosthesis Socket in Below-Knee Amputees Fitted with a Ptb Prosthesis

Abstract

of California, a below-knee prosthesis was introduced in 1957 which was given the name PTB prosthesis (patella tendonbearing prosthesis) because a large part of the body weight was borne by the patella tendon, The socket of the prosthesis is constructed with so-called total contact.After 2 years' experience at GBskolan, Uppsala University, including manufacture of PTB prosthesis for about 60 amputees, a clinical follow-up was performed.One-third of the patients stated that they had a sensation of instability when walking, and about 70 per cent of the prostheses were found to be too large (Lemperg 1965).It was considered that owing to the relatively small surfaces carrying the body weight with this type of prosthesis, excessive movement between the stump and socket, but also too close contact, could give rise to skin changes on and symptoms from the stump.Good contact between the socket of the prosthesis and the amputation stump has been found by Bleck et al. (1963), among others, to reduce the occurrence of skin lesions on the stump.In the present investigation, movements of the stump bone and the patella in relation to the socket of the prosthesis in patients fitted with PTB prostheses were studied roentgenologically.Under four different conditions of weight-bearing, distances between the stump bone and the socket were measured and presented graphically, The roentgenological findings were correlated with 1. the patient's subjective opinion of the stability of the prosthesis,