Postoperative Complications of Intramedullary Nailing for Impending and Pathologic Fractures of the Humerus Due to Bone Metastases-A Systematic Review of the Literature.

Intramedullary nailing (IMN) is a common option for managing impending or pathologic fractures of the humerus secondary to metastatic disease. We sought to assess the (1) early complications, (2) failure rates and mechanisms, and (3) functional outcomes. A systematic review using the PubMed, Embase, and Cochrane databases was performed. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. The study was registered on PROSERO (CRD42023406905). The Strengthening the Reporting of Observational Studies in Epidemiology checklist was used for quality assessment. Studies describing postoperative outcomes of patients with impending or pathologic fractures of the humerus treated with IMN were included. Implant failure was classified into mechanical and nonmechanical causes. Functional outcomes were assessed via the Musculoskeletal Tumor Society (MSTS) score. Overall, 41 studies comprising 1431 patients were included. Early complications occurred in 5.5% of patients, with 2.8% of patients having systemic complications. The overall implant failure rate was 4.9%, and the mean MSTS score at the last follow-up was 79.9%. IMN was associated with good postoperative functional outcomes and low implant failure rates. Systemic complications were the most common type of early complication, and tumor progression was the main cause of implant failure. LEVEL OF EVIDENCE: III.