gms | German Medical Science

Objectives/Interrogation: Scaphoid fractures or nonunion are treated by a variety of surgical techniques. Recently, the number of screws (single or double) for fixation was reported to be important for union. As the double screwing provides two axes of fixation with increased stability, we hypothesized that the union rates would be better especially for the waist nonunion. In this study, we aimed to compare the union rates in patients with single- or double-screw fixation in different clinical presentations of scaphoid problems.

Methods: In total, 41 patients with scaphoid fractures were identified who were operated between October 2016 and June 2018. Of the 29 patients with postoperative follow-up; patients were grouped as acute cases, proximal pole and waist nonunion. Patients were treated with screwing while the proximal pole nonunions were treated additional vascularized bone grafting, and waist nonunions were treated with additional nonvascularized autografting. We determined the union by assessing the radiograph, return the work and pain with palpation at last visit. For statistical analysis, union rates were compared within each group in regards to single- or double-screw fixations.

Results and Conclusions: The mean age of the patients was 31.6 years and the mean follow-up was 7.9 months. There were six patients with fracture, eight patients with proximal pole nonunion, and 15 patients with waist nonunion. Union was achieved in all acute cases independent from the number of screws. Proximal pole union was achieved in 100% (3/3) of patients with double-screw and 80% (4/5) of patients with single-screw fixation (p=0.408). Waist union was achieved in 77.8 % (7/9) of patients with double-screw and 66.6% (4/6) of patients with single-screw fixation (p=0.634). All of the patients with union returned to work and were pain-free with palpation. When the radiographs and computerized tomography images were assessed in detail for the five patients with persisting nonunion, mal-reduction was observed for all of the patients.

In this study, although we observed increased union rates for double screwing for both proximal pole and waist nonunion, the differences were not statistically significant. This might be related to the small number of our cases and further studies with larger sample sizes are needed. Surgery for acute cases arises as a good choice for union independent of screw count. When the nonunion cases were reviewed, not the screw count but the anatomic reduction appears as the most important predictor of union.