Treatment of scaphoid nonunion with dual screw fixation in preventing postoperative humpback deformity

This study aimed to evaluate the treatment of scaphoid nonunion with dual screw fixation in preventing postoperative humpback deformity.

This retrospective study is from December 2010 to December 2021, and 18 patients with scaphoid nonunion were treated with dual screw fixation through the dorsal approach. This study included patients aged 16-60 years with scaphoid nonunion (>6 months) classified as Mack-Lichtman types I-III (mild arthritis), while excluding those with immature osteogenesis (<16 years), osteoporosis (>60 years), prior wrist surgery or fractures, avascular necrosis, advanced degenerative changes (types IV-V), small fragment fixation difficulty, or loss to follow-up. Scaphoid length and angles were assessed on X-rays. Wrist function was assessed based on the Mayo wrist score.

The average age of the participants was 27 (range 17-49) years. The mean time from injury to surgery was 13 (range 6-48) months. There were types I (n=5), II (n=11), and III (n=2) nonunions based on the Mack-Lichtman classification. Nonunion sites included proximal 1/3 (n=4), waist (n=8), and distal 1/3 (n=6). All nonunions healed at a mean of 15 (range 10-28) weeks. The preoperative scaphoid length was 20 (range 17-23) mm, and the data at bone union was 23 (range 21-26) mm. The preoperative scapholunate angle was 46° (range 18°-72°), and the data at bone union was 39° (range 30°-48°). The preoperative radiolunate angle was 24° (range 5°-51°), and the data at bone union was 18° (range 8°-29°). Follow-up lasted for a mean of 52 (range 24-119) months. Mayo wrist score improved from 47 (range 13-64) to 95 (range 78-100). There were 15 excellent, 2 good, and 1 satisfactory results.

In the treatment of scaphoid nonunion, dual screw fixation through the dorsal approach can successfully prevent postoperative humpback deformity. Reduction is maintained to bone union without complications. The technique can be an alternative for the treatment of scaphoid nonunion.