Distal insertions of abductor pollicis longus muscle and arthritis of the first carpometacarpal joint in 104 dissections.

The different types of distal insertions of the tendons of the abductor pollicis longus muscle (APL) were studied in 104 cadaveric hands, and the appearance of the rhizarthrosis in the level of the basal joint of the thumb, as well, in a try to detect possible anatomical relationships. From the anatomical point of view, it was evident that the insertions of the APL muscle are usually multiple (95%), that the insertion to the base of the first metacarpal is constantly present, accompanied in 70% of the cases with an insertion to the trapezium. Finally, the accessory tendon to the thenar eminence was proved to be extremely frequent (42%). Rhizarthrosis has been found in 97% of the dissections. The lateral compartment of the joint surface appeared to be the most frequently affected with arthritis (71%) and probably the starting point of the lesion. But no correlation has been recorded between severe arthritis and any type of distal insertion of abductor pollicis longus muscle. Early tenotomy of some tendons, in order to prevent arthritis of the first CMC joint, cannot be recommended from this study.