Comparison of Results Based on the Number of Kirschner Wires of Different Diameters in Antegrade Intramedullary Fixation of Fifth Metacarpal Neck Fractures

Abstract

Purpose: The purpose of this study was to compare the clinical and radiological results of patients with fifth metacarpal neck fractures using different sizes and numbers of Kirschner wires (K-wire).Methods: A single institutional retrospective review identified 67 patients with a fifth metacarpal neck fracture between January 2015 and July 2020. The minimum follow-up time was 6 months and they were all treated within 6.4 days of the initial injury. Either one K-wire (1.6 mm), two K-wires (1.1 mm), or three K-wires (0.9 mm) was used. We analyzed the bone union period, and K-wire removal period, duration of surgery, total active motion, intramedullary diameter, pre/postoperative shortening, and pre/postoperative angulation clinically. We used a Method of Shortening Stipulated to measure shortening and the Medullary Canal-lateral view method for angulation. The intramedullary diameter was measured in the mid-shaft of the fifth metacarpal bone in the coronal view. Total active motion was measured at the time of follow-up in our outpatient department.Results: Clinical and radiological parameters showed no statistically significant differences. Even though it did not present a statistical significance, the absolute mean duration of surgery was the shortest in a single K-wire group. Conclusion: The clinical and radiological outcomes of surgery were comparable regardless of the number of K-wires inserted. However, we could look forward to gaining potential benefit from shortened operation time in a single K-wire group. Since stable fixation can be obtained even if one K-wire is used, inserting one thick K-wire into the intramedullary canal can be an alternative according to the surgeon’s preference.