Treatment and Outcomes of Chronic Locked Posterior Shoulder Dislocations: A Retrospective Case Series.

Background/Objectives: Chronic locked posterior shoulder dislocations (PSDs) are rare and often misdiagnosed, leading to delayed treatment and complex management. This study retrospectively evaluates surgical outcomes in patients treated for chronic PSDs and reports our clinical experience. Methods: Ten male patients with chronic PSDs treated between 2016 and 2022 at "Vito Fazzi Hospital" (Lecce) were analyzed. Lesions were classified according to the Randelli system (Type 1: 20-50% bone loss; Type 2: >50%; Type 3: fracture dislocation without bone loss; Type 4: multifragmentary fracture dislocation). Surgical options-subscapularis transposition, bone grafting, osteosynthesis, and reverse shoulder arthroplasty-were selected based on lesion type, age, and functional demand. Follow-ups at 1, 3, 6, and 12 months assessed ROM, SF-36, and SDQ scores. Results: Six patients had Type 1 lesions, two Type 2, and two Type 4. The mean diagnostic delay was 6 weeks (up to 5 months). Early follow-ups showed superior ROM and SDQ in patients with reverse prostheses, while at 12 months, cancellous grafts achieved better functional recovery. Subscapularis transpositions resulted in minor internal rotation loss and increased pain. One Type 4 case developed avascular necrosis. Mean healing time was 2.9 ± 0.5 months. Although SDQ differences at 12 months were not significant, internal rotation was reduced by 10% in patients treated with the McLaughlin technique (p < 0.05). Conclusions: Prompt diagnosis and tailored surgical management are key to favorable outcomes in chronic PSDs. While various techniques provide good results, subscapularis transposition should be limited to unstable cases, and osteosynthesis should be used only when strictly indicated due to necrosis risk.