ABNORMALITIES OF THE HOOK OF THE HAMATE IN PATIENTS WITH CARPAL-TUNNEL SYNDROME

The hook of the hamate is an important landmark in endoscopic carpal t unnel release. We studied the incidence of abnormalities of the hook o f the hamate in patients with carpal tunnel syndrome. One hundred thir ty-one consecutive patients presenting with carpal tunnel syndrome und erwent carpal tunnel radiography. Abnormalities of the hook of the ham ate were present in 6 of 131 patients (4.6%). The hook of the hamate w as aplastic in 3 of 131 patients (2.3%). A bipartite hook of the hamat e was present in 1 patient (0.8%). A nonunion of an old fracture of th e hook of the hamate was found in two patients (1.6%). The previously reported incidence of an aplastic hook of the hamate in the general po pulation is 1 of 1,452 (0.06%). The odds ratio revealed a 34-fold incr ease in the risk of hamate abnormalities in the carpal tunnel populati on (p < 0.001). Hook of the hamate abnormalities may be more common th an previously reported.