Modular versus non-modular humeral stems in shoulder arthroplasty for proximal humerus fracture: a multicenter retrospective cohort study.

Atlas, Aaron M; Geffken, Shawn J; Geiselmann, Matthew T; Hershfeld, Benjamin; Modica, Anthony; Cohn, Randy M · J Orthop · 2026

retrospective_cohort · Level III

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Abstract

Evidence directly comparing modular and non-modular humeral stems in shoulder arthroplasty for proximal humerus fractures (PHF) remains limited. This study aimed to compare perioperative outcomes, short-term complications, and patient-reported outcomes following shoulder arthroplasty for PHF using modular versus non-modular humeral stems. Adult patients who underwent shoulder arthroplasty for PHF between January 2014 and July 2023 across a multicenter health system were retrospectively identified using billing data and confirmed by electronic medical record review. Patients were grouped according to humeral stem design as modular or non-modular. Outcomes included operative time, length of stay (LOS), discharge disposition, 1-year adverse events, postoperative American Shoulder and Elbow Surgeons (ASES) score, and visual analog scale (VAS) pain score. Continuous and categorical variables were compared between groups, with statistical significance set at p < 0.05. A total of 319 shoulder arthroplasties in 318 patients were included, including 89 modular and 230 non-modular cases. Modular stems were associated with shorter operative time (115.0 vs. 149.0 min, p < 0.001), shorter LOS (1.9 vs. 3.3 days, p < 0.001), and higher rates of discharge to home (82.0% vs. 67.4%, p = 0.009). Postoperative ASES scores were significantly higher in the modular group (72.4 vs. 63.1, p = 0.02), whereas VAS pain scores were similar between groups (p = 0.1). Most short-term adverse events were comparable, although prosthetic dislocation was more frequent in the modular group (3.4% vs. 0.4%, p = 0.04). Modular humeral stems were associated with shorter operative time, shorter hospital stay, and higher postoperative functional scores after shoulder arthroplasty for PHF. Most short-term complications were similar between groups, although prosthetic dislocation was significantly more common with modular stems.