Radiological Union and Functional Recovery Following JUST UNIC™ Fixation for Comminuted Anatomical Neck Proximal Humerus Fractures: A Single-Centre Retrospective Case Series

Background Comminuted proximal humeral fractures involving the anatomical neck pose challenges in fixation stability and vascular preservation. The JUST UNIC™ (Evolutis, Briennon, France) bilboquet-inspired fixation system has been developed to address these limitations by providing metaphyseal stability with minimal periosteal disruption. This study assesses the clinical, functional, and radiological outcomes following JUST UNIC fixation in this fracture subset. Methods This retrospective single-centre case series included 25 patients with comminuted proximal humerus fractures involving the anatomical neck who underwent fixation with the JUST UNIC™ system between January 2020 and December 2023 at a tertiary care hospital. Clinical outcomes were assessed using the visual analogue scale (VAS), Oxford Shoulder Score (OSS), and serial range-of-motion (ROM) measurements recorded at baseline (preoperative), six weeks, three months, six months, and 12 months (final follow-up). Radiological union, greater tuberosity (GT) resorption, and postoperative complications were evaluated through serial follow-up imaging and clinical review. Results All fractures achieved radiological union by six months. VAS scores reduced from 8.00 ± 0.82 preoperatively to 2.00 ± 0.61 at final follow-up, while OSS increased from 4.48 ± 1.21 to 35.48 ± 1.18. Forward flexion improved from 49.12 ± 5.83° to 141.65 ± 11.99°, abduction from 49.76 ± 4.74° to 136.41 ± 12.64°, external rotation from 30.60 ± 5.86° to 65.47 ± 5.73°, and internal rotation from 29.96 ± 4.59° to 61.76 ± 6.31. GT resorption was observed in 15 patients (60%); however, statistical analysis did not detect a significant association with final VAS, OSS, or ROM outcomes. Postoperative complications occurred in four patients (16%), including one case of avascular necrosis, one varus malalignment, one partial staple prominence, and one superficial haematoma. Conclusion JUST UNIC fixation demonstrated reliable union, progressive functional recovery, and a low complication burden in comminuted anatomical-neck proximal humerus fractures. The implant appears effective in maintaining alignment and facilitating early rehabilitation. Larger controlled studies with long-term follow-up are warranted for comparative validation.