Comparative pathoanatomy of the Asian and Caucasian trapeziometacarpal joint.

The frequency and distribution of idiopathic osteoarthritis (OA) in the upper extremity has been observed to vary considerably among different races. This study seeks to investigate the prevalence of trapeziometacarpal OA and differences in pathologic anatomy in comparable populations of Caucasian and Asian peoples. Sixty-one postmortem Japanese, Chinese and Indian specimens were examined for integrity of both the stabilising soft tissue structures and articular surfaces. Chondromalacia and eburnation were assessed by location in the joint relative to previously described patterns of disease in Caucasian specimens. Among 35 Japanese specimens, 23 (66%) were found to have completely normal joint surfaces, 5 (14%) had chondromalacia limited to the dorsal surfaces, 2 (6%) had chondromalacia on the volar surfaces, and 5 (14%) exhibited eburnation consistent with advanced degenerative disease. A similar distribution was noted for the 22 Chinese specimens. When present, the pattern of arthritic disease was identical to that seen in Caucasian joints; eburnation of surfaces was only seen in the volar compartment and dorsal joint cartilage was typically spared. Detachment of the volar beak ligament was evident in all joints with eburnation, and degeneration of the metacarpal insertion was present in specimens with volar chondromalacia. The concavoconvex configuration of the joint surfaces was more shallow in Japanese and Chinese specimens than comparable Caucasian joints. A similar study of Caucasian joints demonstrated only 25% with normal articular surfaces, 10% with dorsal chondromalacia as a lesion indicative of physiologic aging, 15% with volar chondromalacia as a prearthritic progressive lesion, and 50% with eburnation indicative of end-stage arthritic disease. Based upon the study of postmortem material, the anatomical prevalence of trapeziometacarpal joint osteoarthritis is considerably less in the Japanese and Chinese than in the Caucasian race.(ABSTRACT TRUNCATED AT 250 WORDS)