Functional outcomes after reverse shoulder megaprosthesis following resection of malignant bone tumor in the proximal humerus: a systematic review and meta-analysis

After resection of tumors in the proximal humerus, orthopedic oncologic surgeons are able to restore the shoulder function of patients with reverse shoulder megaprosthesis. Information about expected postoperative physical functioning is required to guide patient expectations, identify abnormal recovery, and set treatment goals. The aim was to provide an overview of functional outcomes after reverse shoulder megaprosthesis in patients after proximal humerus resection. This systematic review searched studies in MEDLINE, CINAHL, and Embase up to March 2022. Data on performance-based and patient-reported functional outcomes were extracted using standardized data extraction files. A meta-analysis with random effects model was performed to estimate outcomes after 2-year follow-up. The search identified 1089 studies. Nine studies were included in the qualitative analysis and six in the meta-analysis. Forward flexion range of motion (ROM) after 2 years was 105 degrees (95% Confidence Interval [CI]: 88-122, n = 59), abduction ROM 105 degrees (95% CI: 96-115, n = 29), and external rotation ROM 26 degrees (95% CI: 1-51, n = 48). The mean American Shoulder and Elbow Surgeons score after 2 years was 67 points (95% CI: 48-86, n = 42), mean Constant-Murley-Score 63 (95% CI: 62-64, n = 36), and mean Musculoskeletal Tumor Society score 78 (95% CI: 66-91, n = 56). The meta-analysis shows acceptable functional outcomes 2 years after reverse shoulder megaprosthesis. However, outcomes may well differ between patients as reflected by the CIs. Further research should focus on modifiable factors associated with impaired functional outcomes.