High prevalence of radiographic changes at prothesis-bone interface after cemented and uncemented massive prosthesis replacement following proximal humeral resection for bone tumor. A retrospective study of 45 surgeries.

BACKGROUND: Managing bone tumors of the proximal humerus frequently involves an extensive bone resection, which needs to be addressed by using shoulder massive arthroplasty (SMA) for reconstruction. Mechanical complications are frequent with these implants. Few studies focus on the radiologic modifications around the stem, which can be an early sign of mechanical stress. QUESTIONS/PURPOSES: The aim of this study was to answer these questions: 1) What is the prevalence of bone-implant radiographic anomalies after SMA? 2) What are the complications and the risk of reoperation after massive arthroplasty of the proximal humerus for bone tumor? PATIENTS AND METHODS: This monocentric, retrospective study involved 41 patients with massive arthroplasty of the proximal humerus for bone tumors. Median follow-up was 23.0 months (0-161). Median age was 56.0 years (18-84). Mean resection was 120 mm (50-220), 22 (53.6%) were Reverse Shoulder Arthroplasties (RSA), 27 (65.9%) were cemented, 6 (14.6%) involved a resection of the axillary nerve or more than 50% of the deltoid muscle, 24 (58.5%) received an attachment tube. RESULTS: 8 patients (19.5%) presented a radiolucent line on the x-rays, and 17 (41.5%) presented stress-shielding. Ten (24.4%) patients were reoperated (6 instabilities, 1 deep wound infection, 1 early loosening, 1 late loosening, 1 periprosthetic fracture). The choice of RSA instead of Hemi-Arthroplasty (HA) was the only statistically significant risk factor of reoperation (RR = 8.4; p = 0.007). CONCLUSION: Whether patients frequently presented radiologic anomalies (radiolucent line, bone resorption), it was not a cause of revision. Instability is the main complication after massive arthroplasty of the proximal humerus. LEVEL OF EVIDENCE: IV, retrospective study.