Reverse Total Shoulder Arthroplasty for Failed Osteosynthesis in Proximal Humerus Fractures: Outcomes and Challenges

Background Proximal humerus fractures (PHF) are among the most common humeral fractures, particularly affecting elderly individuals, often following low-energy trauma. While conservative treatment is often preferred in geriatric patients, surgical management remains indicated for displaced fractures. Reverse total shoulder arthroplasty (RTSA) has increasingly been used as a primary treatment option for complex PHF, especially Neer three and four-part patterns. However, in the setting of failed osteosynthesis, there is a lack of evidence regarding the role and outcomes of RTSA. Methods A retrospective study of nine patients who underwent RTSA for failed osteosynthesis of PHF between 2018 and 2023 was conducted. Demographic and clinical data were collected from electronic medical records. The patients were clinically reassessed, and preoperative imaging was reviewed to identify failure mechanisms. Functional outcomes were assessed using the Constant Score, Visual Analog Scale (VAS) for pain, and active range of motion (AROM), with a minimum follow-up of 12 months. Results The cohort included predominantly female patients (mean age: 67 years). Most initial fractures were Neer two-part (n=6; 67%), treated with open reduction and internal fixation (ORIF) using plates and screws (n=5; 83%) or a proximal humeral nail (n=1; 17%). Two Neer three-part fractures (n=2; 22%) and one metaphyseal fracture (n=1; 11%) were also included. Failure mechanisms included varus collapse with screw pull-out (n=4; 45%), nail pull-out (n=2; 22%), avascular necrosis (n=2; 22%) and one case of non-union (11%). All patients presented with persistent pain and dysfunction as indications for RTSA. A standardized surgical technique was employed in all cases and tuberosity reattachment was attempted when feasible. At the one-year follow-up, mean AROM was 90° of abduction, 110° of forward flexion, external rotation reaching the nape of the neck, and internal rotation reaching the lateral side of the buttock. Mean Constant Score improved from 35 preoperatively to 88 postoperatively, and VAS scores decreased from seven to three. One case of postoperative traumatic dislocation was recorded. Mean follow-up duration was 27 months. Conclusion RTSA is an effective salvage procedure following failed osteosynthesis of PHF, offering reliable pain relief and functional improvement. Despite a small sample size, this study reinforces the utility of RTSA in complex revision scenarios. Calcar comminution and poor bone quality were identified as potential risk factors for initial fixation failure, emphasizing the importance of anatomic reduction and metaphyseal screw placement during primary osteosynthesis.