The trapeziometacarpal joint. Tenotomy of the accessory tendons in early osteoarthritis.

The TMC joint is an articulation with special articular surfaces adapted to produce simple (nonrotatory) and complex (rotatory) metacarpal movements. Its articular anatomy and biomechanics are closely related to the pathogenesis of osteoarthritis. The joint works under high transarticular compressive-shearing forces. In osteoarthritic thumbs, the articular forces are increased because of the constant presence of accessory APL tendons, almost exclusively of the digastric type. Other factors should be considered in the pathogenesis of TMC joint osteoarthritis, such as repetitive use of the thumb under unfavorable patterns of function) strong side-to-side pinch grips, thumb with the tendency to maintain in reposition), cartilage aging, hormonal disturbances in women, and general osteoarthritic disease. Osteoarthritic thumbs in stages I and II that have failed to respond to conservative treatment are candidates to unload the joint by tenotomy of the transarticular accessory tendons. Long-term results have been very satisfactory (97%), eliminating or substantially reducing pain and returning patients to their activity. The procedure is contraindicated in severe (stage III) TMC joint osteoarthritis and in primary articular instability.