Intercalary prosthetic replacement is a reliable solution for metastatic humeral shaft fractures: retrospective, observational study of a single center series

BACKGROUND: Treatments for metastatic fracture of the humeral shaft continue to evolve as advances are made in both oncological and operative management. The purposes of this study were to critically evaluate the effectiveness of intercalary endoprostheses in treating metastatic humeral shaft fractures and to clarify the surgical indications for this technique. METHODS: Sixty-three patients treated surgically for 66 metastatic fractures of the humerus shaft were retrospectively reviewed. Intramedullary nailing (IMN) was performed in 16 lesions, plate fixation (PF) in 33 lesions, and prosthetic replacement in 17 lesions. The operative time, intraoperative blood loss, and postoperative complications were noted. The function of the upper extremities was assessed by the Musculoskeletal Tumor Society (MSTS) score and American Shoulder and Elbow Surgeons (ASES) score. All included patients were followed until reconstructive failure or death. RESULTS: The operative time was relatively shorter in the prosthesis group than in either the IMN group (p = 0.169) or PF group (p = 0.002). Notably, intraoperative blood loss was significantly less in the prosthesis group than in either the IMN group (p = 0.03) or PF group (p = 0.012). The average follow-up time was 20.3 (range, 3–75) months, and the overall survival rate was 59.7% at 12 months and 46.7% at 24 months. One rotator cuff injury, 3 cases of iatrogenic radial nerve palsy, 5 cases of local tumor progression, and 1 mechanical failure occurred in the osteosynthesis group, whereas one case of aseptic loosening of the distal stem and one case of local relapse were observed in the prosthesis group. There were no significant differences in functional scores among the three groups. CONCLUSIONS: Intercalary prosthetic replacement of the humeral shaft may be a reliable solution for pathologic fractures patients; it is indicated for lesions with substantial bone loss, or accompanied soft tissue mass, or for those patients with better prognosis. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12957-021-02250-1.