Deltoid Ligament Repair Does Not Improve Radiographic or Clinical Outcomes in Weber Type C Pronation-External Rotation Ankle Fractures: A Randomized Controlled Trial

OBJECTIVE: To determine the clinical utility of deltoid ligament (DL) repair in Weber type C pronation-external rotation ankle fractures. METHODS: Design: Randomized controlled trial. SETTING: A tertiary referral university hospital. PATIENT SELECTION CRITERIA: Between January 2022 and August 2024, patients with Weber type C ankle fractures (OTA/AO type 44C) and DL injury were enrolled and randomly assigned to either DL repair or no repair groups after the fracture fixation strategy was established based on preoperative imaging. OUTCOME MEASURES AND COMPARISONS: Radiographic parameters, including the medial clear space (MCS), and talar tilt (TT) were assessed on standing, gravity stress, and valgus stress views at 3, 6, and 12 months postoperatively. Clinical outcomes were assessed using Foot and Ankle Ability Measure (FAAM) scores. RESULTS: Seventy-one patients (no repair: n=36; DL repair: n=35) completed the 12-month follow-up. Demographics and preoperative parameters were comparable between the repair and no-repair groups (all P > 0.05), including mean age (33.0 vs 33.4 years), female distribution (27.8% vs 28.6%), preoperative MCS on gravity stress view (8.6 vs 9.7mm), and preoperative TT on gravity stress view (3.8° vs 4.1°). All patients underwent lateral malleolus ORIF using anatomical plates; posterior malleoli were fixed based on CT-defined criteria (fixation rates: 72.2% vs 77.1%; P = 0.634). MCS remained comparable across all views and time points (all P > 0.05); 12-month valgus stress MCS was 3.8 ± 0.8 mm (no repair) vs 4.2 ± 1.1 mm (DL repair). At 3 months, the no repair group exhibited significantly greater valgus TT on gravity stress (3.4 ± 1.0° vs 0.6 ± 1.0°; P = 0.001) and valgus stress views (4.9 ± 1.0° vs 0.2 ± 0.7; P = 0.001). These differences resolved by 12 months (1.2 ± 0.8° vs 0.4 ± 1.2° on gravity stress view, and 1.1 ± 1.0° vs 0.3 ± 1.2 on valgus stress view; all P > 0.05). FAAM scores improved significantly over time in both groups (P < 0.05); specifically, the FAAM- activities of daily living score increased from approximately 61-63% at 3 months to 89-90% at 12 months in both groups. CONCLUSIONS: In Weber type C fractures, DL repair provided superior early talar stability compared with no repair. While the no repair group exhibited transient valgus instability at 3 months, clinico-radiographic parameters became comparable by 12 months. LEVEL OF EVIDENCE: Level I, randomized controlled trial.