(P 277) REVERSE TOTAL SHOULDER ARTHROPLASTY MAINTAINS GLOBAL FUNCTION OF THE UPPER EXTREMITY IN PATIENTS WITH ONCOLOGIC DISEASE OF THE PROXIMAL HUMERUS

Objective: Musculoskeletal tumors (MST) of the proximal humerus are often treated with complete resection of the bony lesion along with all surrounding affected tissues. A radical resection may result in deficient range of motion of the shoulder girdle, resulting in the patient having difficulties performing everyday activities. Reverse total shoulder arthroplasty (RTSA) can be performed in patients with MSTs of the proximal humerus that spare the deltoid to regain shoulder range of motion.

Methods: A retrospective chart review was conducted from September 2020 to January 2023 that included patients who underwent RTSA for malignant or benign musculoskeletal tumors. Patient demographics including gender, age and BMI were collected. Other data collected include type of tumor, pain scores, and range of motions measurements.

Results: Three (3) patients (2 Male, 1 Female) with an average age of 62.7 years (range: 49-71) underwent RTSA for musculoskeletal tumors with an average follow up time of 20.7 months (range: 9-42; median=11). Overall survival was 67% (n=2). The average BMI was 24.6 kg/m2 (range: 22.1-27.8). Malignant tumors included a primary grade 2 chondrosarcoma (n=1), and metastatic squamous cell carcinoma (n=1). Benign tumors included synovial chondromatosis (n=1), in a patient with significant osteoarthritis. All patients underwent a deltopectoral approach (Right: 2, Left: 1). Patients with malignant tumors underwent radical resection of the proximal humerus with an average resection of 8.5cm (range:7-10cm). All patients had an approximate humeral component neck-shaft angle of 135deg. Cement was used for distal fixation on all patients (n=3) while long humeral stems of 100mm were used in patients with malignant tumors (n=2). Pain scores improved from an average of 9 (SD=1.5; range:7-10) to 0.7 (SD=1.2; range:0-2) at longest follow up. Average abduction was 92.5deg (SD=3.5,n=2) and forward flexion was 132.5deg (SD=53,n=2). Dislocation, glenoid loosening, acromial and spine fractures were not demonstrated in any patient. There were no neurovascular complications or prosthetic joint infections.

Conclusion: Patients who underwent RTSA for musculoskeletal oncologic disease of the proximal humerus maintained adequate forward flexion, and abduction, while achieving improvements in pain.