The trapeziometacarpal (TMC) joint at the base of the thumb is a common place for osteoarthritis. Efforts have been made in the past to replace the joint with silicon implants. The implants didn't wear well and many patients had a reaction to the material.

A Swedish company with previous success designing implants for the spine designed the biodegradable TMC joint spacer. The FDA approved the new thumb joint spacer for use in the Uunited States in September of 2004.

The material used in the spacer can be broken down by a process called hydrolysis. This means water is used to split the chemical bonds holding the implant together. Hydrolysis of this kind in the body is done by the body's own natural enzymes.

It takes about six years for this process to occur. Only about half the implant is actually degraded. The rest remains part of the tissue implantation.