One-year clinical outcomes after fixation of condylar head fractures using a reduced-head PEO-modified WE43 biodegradable magnesium screw.

INTRODUCTION: Surgical management of condylar head fractures (CHF) remains challenging, and the optimal fixation material is still debated. Biodegradable magnesium alloys may serve as an alternative to titanium, eliminating the need for implant removal. This study evaluated clinical and three-dimensional (3D) radiographic outcomes of a reduced-head, cannulated WE43 magnesium-alloy screw with a plasma electrolytic oxidation surface (HBS-Mg). METHODS: In this retrospective single-arm, single-centre cohort study (STROBE-compliant), 20 patients with 22 CHFs were treated using HBS-Mg. Clinical outcomes (mouth opening, mandibular mobility, occlusion) and 3D radiographic parameters (condylar volume, surface area, and surface congruence assessed by root mean square [RMS] deviation) were analysed over a 1-year follow-up. RESULTS: Maximum mouth opening improved significantly from 23.6 ± 6.9 mm (<50 days) to 45.1 ± 5.9 mm (>360 days; p < 0.0001), with stable occlusion achieved after 100 days. No permanent facial nerve palsy or implant-related complications occurred. Condylar volume and surface area decreased significantly (-24.0 ± 14.2%, p = 0.0051; -24.6 ± 11.9%, p < 0.0001). Surface deviations ranged from 1.4 to 1.7 mm, mainly during the first six months. CONCLUSION: HBS-Mg fixation yielded favourable clinical outcomes and stable functional recovery despite significant 3D condylar remodelling during the first postoperative year. The observed remodelling indicates that the use of a reduced-head, PEO-coated magnesium screw did not prevent postoperative condylar changes, although these changes were not associated with functional impairment within the study period.