1. Arthroplasties of the first metatarsophalangeal joints in rabbits have been examined histologically after varying periods of immobilization and subsequent motion.
2. In this laboratory model, motion started one week after surgery consistently produced the best joint as evidenced by histological examination.
3. The proposition is presented that wound repair should be looked upon as an inflammatory response and that by proper control of local factors at the wound site it should be possible to direct the tissue response into channels leading to the formation of the desired mature tissue.