BackgroundReverse total shoulder arthroplasty (RTSA) has progressively been utilized for reconstruction following wide resection of proximal humerus neoplasms. The purpose of the study is to evaluate complications, reoperation rates, range of motion (ROM), patient-reported outcomes, and postoperative radiographic data to better understand patient outcomes following oncologic associated RTSA. MethodsTwenty patients who underwent RTSA reconstruction for the treatment of an oncologic process from 2011 to 2019 were identified. Demographic, pathology, technical, categorical, and physical examination data were collected from the electronic medical record. The Henderson classification was used to categorize complications. Acromion to proximal humerus cut distance (resection length), stem tip to ulnohumeral joint distance, and working stem length were measured on most recent radiographs. Patients were contacted via phone to obtain the Musculoskeletal Tumor Society score; the Disabilities of the Arm, Shoulder, and Hand score; the American Shoulder and Elbow Surgeons score; and the Simple Shoulder Test score. Descriptive statistics were calculated for demographic data, tumor and disease characteristics, adjuvant treatment, complications, and patient-reported outcome measures (PROMs). Radiographic data, ROM, and reoperation were further analyzed with Spearman rank correlation and Mann-Whitney U testing. ResultsThe overall complication rate was 35%, including 4/20 with dislocations (Henderson I), 3/20 with aseptic loosening (Henderson II), 1/20 with a periprosthetic fracture (Henderson III), 1/20 with a periprosthetic joint infection (Henderson IV), and 1/20 with a radial nerve injury. There were no cases of tumor progression (Henderson V). All patients with complications required reoperation. Measured radiographically, the mean distance from stem tip to ulnohumeral joint was 13.4 cm. A shorter stem tip to ulnohumeral joint distance was significantly associated with reoperation (10.0 ± 5.0 cm vs. 14.9 ± 5.0 cm, P = .04). At final follow-up, mean flexion and abduction were 90.4 degrees and 83.6 degrees, respectively. Of note, larger resections were negatively associated with flexion (Spearman R = −0.896, P = .003) and abduction (Spearman R = −0.761, P = .028) at final follow-up. Mean PROMs were Musculoskeletal Tumor Society score 12/30, Disabilities of the Arm, Shoulder, and Hand score 58/100, American Shoulder and Elbow Surgeons score 26/100, and Simple Shoulder Test score 3/12. ConclusionsThis study corroborates previously published data on complication rates and ROM following oncologic RTSA, while PROMs were lower. Resection length and deltoid release correlate with functional outcomes and the risk of reoperation. The RTSA remains a viable treatment option for oncologic processes about the glenohumeral joint in appropriate patients.