(P 482) COMPARISON OF RECONSTRUCTIVE TECHNIQUES FOR METASTATIC DISEASE IN THE PROXIMAL HUMERUS

Objective: The proximal humerus is a common location for metastatic disease, and numerous options are available for limb-salvage surgery in patients with impending or pathologic fracture. Endoprosthetic composites are often utilized for reconstruction with both hemiarthroplasty (HA) and reverse arthroplasty (RA) constructs being described. RA constructs have been shown to have improved functional outcomes in patients undergoing reconstruction for osseous lesions, but no studies have compared techniques in metastatic disease alone. The aim of this study is to compare functional outcomes and complications between HA and RA techniques in patients undergoing endoprosthetic reconstruction for proximal humerus metastases.

Methods: A total of 49 (25 male, 24 female) patients undergoing intraarticular resection of the proximal humerus for metastatic disease were retrospectively reviewed. Reconstructions included 31 HA constructs and 18 RA constructs. The majority (88%) of patients presented with pathologic fracture, with the most common diagnoses including renal cell carcinoma (47%), multiple myeloma (14%), and breast carcinoma (10%). All procedures were performed via the deltopectoral approach, and all implants were fixed via cementation. Average resection length was 11±3 cm, resection was above the deltoid insertion in 84% of cases, and the axillary nerve was preserved in 98% of cases. Average follow up was 2.6±3.5 years.

Results: Patients with RA reconstructions had significantly better post-operative forward elevation (73° vs. 37°, p=0.0005), though there was no difference in post-operative external rotation between groups. RA patients also had significantly higher Simple Shoulder Test scores (3.6 vs. 2.5, p=0.048). Patients with HA reconstruction experienced significantly more complications (n=18, 55% vs n=2, 9%, p=0.0014), with instability being the most common complication (n=14, 45% vs. n=2, 9%, p=0.0079). Two patients (both HA reconstructions) experienced a periprosthetic fracture about the distal implant. No patients underwent revision surgery.

Conclusion: In this series, patients with metastatic disease of the proximal humerus had improved post-operative range of motion as well as higher functional outcome scores when undergoing reconstruction with a reverse endoprosthetic construct compared to a hemiarthroplasty construct. For patients with metastatic disease of the proximal humerus requiring reconstruction, preference for reverse endoprosthetic composites should be given over hemiarthroplasty endoprosthetic composites.