Preliminary experiences with the CIR casting system for transtibial prosthetic sockets

A sand-casting technique for transtibial sockets was applied to 28 amputees in 2005. Although this meant an improvement in the quality of fitting as compared to historical reports with plaster of Paris casting, a total contact required three (two to five) stump socks. Continuing research leads the inventor, Dr Y. Wu, to replace the sand with micro polystyrene beads and simplify the equipment by eliminating the need for fluidization of silica sand by an air compressor during casting of the amputation stump. In a pilot series of 10 transtibial amputees, socket casting was performed with the new CIR casting technique and compared with the former sand-casting technique conducted by the same Category-I prosthetist. It was possible to obtain a good fit in eight out of 10 cases, which is an improvement from 19 out of 28 in the old series. Furthermore, there was a highly significant reduction in circumference measurements on the positive model with the new technique as compared to sand-casting.