Osteoarthritis at the base of the thumb. The concept of monoarticular reconstruction.

Osteoarthritic affection of the base of the thumb involving 148 hands has been studied. Isolated osteoarthritis of the trapezio-metacarpal joint was found to be the largest group including a total of 111 hands. Reconstruction of this particular joint by a new technique is described and long-term results reported. A small series of isolated osteoarthritis of the trapezio-scaphoid joint is presented and reconstruction by replacing the affected articular surface of the carpal scaphoid is described. Osteoarthritic involvement of more than one of the articular surfaces of the trapezium was found in a group of 31 hands. In all of them the trapezio-metacarpal joint was predominantly affected. The rationale for monoarticular reconstruction of the trapezio-metacarpal joint, regardless of the extent of involvement, is discussed in detail.