Some of these knees are very strong and durable owing much of their strength to the geometry of the knee as well as the material used. Steel is certainly strong but it is relatively heavy. Because steel is strong, it can be used to create small components that may rely more on the strength of the material than the geometry of the design. Small knee units used for endoskeletal prostheses were originally made of steel. The material is fairly heavy however very little material is needed to construct these knees.
Titanium is a strong, lightweight alternative.
The penalty for using titanium is higher cost. Many of the endoskeletal components originally designed of steel are now available in titanium. As with all of the trade-offs that must be considered in choosing prosthetic components, one must carefully weigh the advantages and disadvantages and choose wisely. The most expensive, strong and lightweight materials may not provide any discernible advantage over less exotic options if chosen inappropriately. Liners and Sleeves Liners are the materials that are either made during the fabrication process to fit inside the socket or those materials added after the leg is in use in order to accommodate for shrinkage of the residuum.