Incidence of a septum in the first dorsal compartment and its effects on therapy of de Quervain's disease.

Because there has been no study of the presence of a septum in the first dorsal compartment of the wrist in Asians and there is no method of conservative treatment of de Quervain's disease based on the presence of this septum, the authors have evaluated this septum in a large Asian population. Two-hundred wrists in 100 Asian cadavers were dissected. The presence of the septum was documented by removing the abductor pollicis longus (APL) tendon from its tunnel in the first dorsal compartment and observing through the same tunnel if there was a septum to prevent immediate access to the extensor pollicis brevis (EPB) tendor. A septum was present in 77.5% of wrists. When the septum was present, the resultant subcompartment for the EPB was quite narrow. Given the high incidence of the septum, therapy of de Quervain's disease could reasonably be modified accordingly. For instance, to improve the success rate for local steroid injection, the solution of steroid should aim at reaching both subjcompartments by redirecting the course of the injecting needle. As for surgical release, adequacy could be enhanced by the realization by the surgeon of the possible presence of the septum.