Greater Arc Perilunate Injury Through a Lunotriquetral Carpal Coalition: A Case Report.

CASE: A 31-year-old Caucasian man presented with a greater arc perilunate variant injury after falling from a friend's shoulders onto an outstretched hand. Imaging revealed a minimally displaced scaphoid waist fracture and a nondisplaced transverse fracture through a previously unrecognized lunotriquetral coalition. A volar intercalated segmental instability (VISI) deformity was present. Open reduction with osseous fixation (a headless compression screw for the scaphoid waist fracture and 3 Kirschner wires across the midcarpal joint) and repair of the torn volar ligaments partially restored the carpal alignment. At 1 year postoperatively, the patient had regained approximately 90% of grip and pinch strength, 70% of wrist flexion, and 80% of wrist extension when compared with the contralateral, uninjured side. Despite persistent VISI alignment, he was satisfied with the outcome and had returned to his preoperative employment and recreational activities.

CONCLUSION: A high index of suspicion for a perilunate injury should be maintained for all scaphoid fractures, particularly when abnormal anatomy is present.