(P 263) HEMI- VS. REVERSE SHOULDER ARTHROPLASTY OUTCOMES FOLLOWING PROXIMAL HUMERAL ONCOLOGIC RESECTION

Objective: Proximal humeral tumors that require resection to achieve oncologic control often leads to significant bone and soft tissue loss, which may necessitate joint reconstruction to restore shoulder function. Hemiarthroplasty (HA) and Reverse Shoulder Arthroplasty (RSA) are the two primary options for reconstruction following proximal humeral oncologic resection. The objective of this study was to determine if hemiarthroplasty versus reverse shoulder arthroplasty following proximal humeral oncologic resection provides superior functional outcomes and lower rates of implant complications and failure.

Methods: A retrospective review of patients who underwent proximal humeral tumor resection with RSA or HA between 2010 and 2024 was performed. Patient data including demographic information, and clinical outcomes were obtained from electronic medical records. The primary outcome measure was rates of instability, implant related complications, or complications necessitating revision surgery. Functional outcomes were determined by range of motion in several planes. Continuous variables analyzed with independent t-tests, categorical variables assessed by the Rao-Scott Chi-Square test, and Fisher’s exact test was used for variables with expected frequencies < 5. Statistical significance was set at an alpha level of 0.05.

Results: We retrospectively reviewed 72 patients who had undergone a proximal humerus tumor resection followed by reconstructions with HA or RSA. Of the total number of patients, 62 (86%) underwent HA and 10 (14%) underwent RSA.
Preoperatively, patients who underwent HA versus RSA had similar age, gender, race/ethnicity, smoking status, diabetes prevalence, and BMI. However, patients undergoing HA versus RSA had differing cancer diagnoses, with those undergoing HAs having higher prevalence of primary bone sarcoma and those undergoing RSAs having higher prevalence of soft tissue sarcoma involving bone and metastatic cancer to bone or multiple myeloma (p=0.008).
Operative duration was similar for HAs and RSAs, but resection length was significantly greater for HAs (HA: 12.57 cm; RSA: 8.57 cm; p=0.038).
Postoperatively, there was no significant difference in instability, all cause implant complications, and failure rates between HA and RSA. Notably, HA patients had a significantly longer mean follow-up (33.18 months) compared to RSA patients (13.48 months) (p < 0.001).
In terms of ROM, FE was consistently higher in RSA patients following surgery. Although all these findings were non-significant, RSA patients showed an upward trajectory of FE to greater than 90 whereas HA patients’ FE remained stable at around 45 throughout follow-up. Yet, RSA patients experienced significantly worse ER than HA patients throughout the follow-up period (p=0.044).

Conclusion: For proximal humeral oncologic resection with shoulder arthroplasty, failure rates were similar for both HAs and RSAs, with RSAs showing a slight improvement in FE ROM post-operatively.