To evaluate the classification and treatment results about the injury of carpometacarpal (CMC) joint with the fracture of hamate.

The authors categorized into 3 types (I, II, III) according to the location of injured CMC joint and type II was subdivided into 2 type (a, b) according to the size of coronal fragment of hamate fracture-type I: fracture-dislocation of 5th CMC joint with small-sized fragment or avulsion fracture of hamate, type IIa: fracture-dislocation of 4th and 5th CMC joint with small-sized fragment or avulsion fracture of hamate, type IIb: fracture-dislocation of 4th and 5th CMC joint with coronal fracture of hamate body presenting an oblique or coronal splitting fracture, and type III: type II injury associated with injury of 3rd CMC joint or coronal plane fracture of capitate. All cases were carried out the operative treatment. And radiologic results and clinical results were evaluated.

Type I were 2 cases, type IIa 4, type IIb 5, and type III 3. Twelve of 14 cases were excellent or good results, 1 case (type III) was fair, and 1 case (type IIa) was poor. All cases obtained anatomic reduction of CMC joint. But, the posttraumatic arthritis was observed in 1 case (poor) and the displacement of non-fixed hamate fragment was observed in 1 case (fair).

We think that it may get more favorable outcomes by the fixation of the relative large fragment of hamate with anatomical reduction of CMC joint.