The incidence of intrinsic and extrinsic ligament injuries in scaphoid waist fractures.

PURPOSE: To determine the incidence of associated intrinsic and extrinsic ligament injuries in patients with a nondisplaced or displaced scaphoid waist fracture.

METHODS: During a 3-year period, a study of all scaphoid fractures was performed at our institution. Diagnosis was confirmed by plain radiographs, computed tomography, and magnetic resonance imaging. A 3-part anatomic classification was used to categorize the scaphoid fractures. The study population comprised 40 patients with 41 scaphoid waist fractures who had wrist arthroscopy for treatment and evaluation of the scaphoid fracture and associated carpal injuries.

RESULTS: We observed fresh intrinsic ligament injuries in 34 of 41 wrists. In 29 cases, the scapholunate ligament was injured, with complete rupture occurring in 10 wrists. The lunotriquetral ligament was injured in 8 wrists, and the triangular fibrocartilage complex was injured in 11 wrists. Statistically, the number of intrinsic ligament injuries did not differ between nondisplaced and displaced scaphoid fractures (p> .30).

CONCLUSIONS: In this study of acute scaphoid waist fractures, the overall incidence of associated ligament injuries was surprisingly high, at 34 of 41 wrists. Complete scapholunate ligament rupture was found in 10 of 41 wrists. This incidence is higher than previously reported and emphasizes the need for careful assessment of the intrinsic and extrinsic ligaments, particularly the scapholunate ligament, before deciding on treatment.