A finger function simulator and the laboratory testing of joint replacements.

The design of a metacarpophalangeal (MCP) joint function simulator was undertaken and resulted in a versatile machine which offers the facility to apply both dynamic and static loading to a joint, following closely the physiological levels and patterns imposed in vivo. An additional feature was the opportunity to investigate the effect of varying the degree of joint instability. Long-term tests performed on Swanson silastic implants have produced failures of the kind seen clinically, which is very encouraging since it would seem to validate the claim that the simulator successfully imitates the finger function.