Treatment of neck fractures of the fifth metacarpal with MIROS (minimally invasive reduction and osteosynthesis system): a retrospective case-series

Background: Neck fractures of the fifth metacarpal are frequent hand injuries. Surgical intervention is indicated for fractures with > 30° flexion angulation, rotational deformities, or shortening > 3 mm. Various techniques, including K-wire fixation, plating, and minimally invasive systems can be used. This study evaluates the efficacy of the Minimally Invasive Reduction and Osteosynthesis System (MIROS) for treating displaced fifth metacarpal neck fractures. Methods: A retrospective review of patients treated with MIROS between 2019 and 2024 was conducted. Patients aged 18-80 years with unstable neck fractures of the fifth metacarpal were included, excluding open, pathological, or polytrauma cases. Radiological outcomes were assessed through Palmar Tilt Angle (PTA) and Lateral Tilt Angle (LTA) measurements pre- and postoperatively. Secondary outcomes included surgery duration, radiation exposure, healing time, and complications. Results: Fifty-two patients (44 men) were included, with a mean age of 35.1 ± 15.1 years. Postoperative improvements in PTA (from 35.4 ± 16.6 to 15.9° ± 9.3; p < 0.0001) and LTA (from 56.7 ± 14.7 to 29.3 ± 11.9; p < 0.0001) were significant. Mean surgery duration was 37.4 ± 18.1 min, and radiological healing time averaged 2.3 ± 1.4 months. The complication rate was 7.7%, with three cases of K-wire infection and one case of finger overlap. Conclusion: MIROS demonstrated effective anatomical restoration, and a low complication rate, proving to be a reliable surgical technique for fifth metacarpal neck fractures. Further prospective, multicenter trials with longer follow-up are necessary to validate these findings.