90 Hook of the Hamate Fracture

Hook of the Hamate Fracture

Hema N. Choudur, Anthony G. Ryan, and Peter L. Munk

Clinical Presentation

While playing golf, a young man experienced sudden, agonizing pain along the ulnar aspect of his palm immediately after a forceful drive. Over the subsequent hours, swelling developed at that site with point tenderness, distal and radial to the pisiform bone. On examination, his grip strength was decreased, and there was weakness of the hypothenar muscles with paresthesia in the fourth and fifth fingers.

Figure 90A

Figure 90B

Figure 90C

Radiologic Findings

Except for soft-tissue swelling along the volar aspect of the wrist joint distally, no definite abnormality is noted on the plain radiographs (Figs. 90A, 90B). Only on the subsequent CT (Fig. 90C) was the hook of hamate fracture convincingly demonstrated.

Diagnosis

Hook of hamate fracture.

Differential Diagnosis

Stress fractures of the hamate secondary to chronic repetitive trauma, as occurs in golf, hockey, and tennis.

Discussion

Hook of humate fractures result in high nonunion rates with conservative measures. Therefore, it is very important to detect and treat them. Using conventional x-ray projections, a sensitivity of 72%, a specificity of 88%, and an accuracy of 80% in detection of the fracture are typical. Using CT, the sensitivity is 100%, the specificity 94%, and the accuracy 97%; also, setup for CT scanning is less uncomfortable for the patient.

Fractures of the body of the hamate are much less common than fractures of the hook. They are often associated with fourth and fifth carpometacarpal fracture-dislocations. Fractures of the body may occur as a result of axial force transmitted through the metacarpals or from a direct blow to the ulnar aspect of the wrist.