Re-evaluating Surgical Treatment Protocol for Unstable Proximal Humerus Fractures: Emphasizing Soft Tissue Preservation via Minimally Invasive Approach over Structural Allograft Augmentation in Deltopectoral Approach: a Single-center Retrospective Study.

Background: Managing unstable proximal humerus fractures (PHFs), particularly in elderly patients, is challenging due to the need to balance stability with minimizing surgical trauma. The conventional deltopectoral approach with structural allograft for medial support is widely used but can involve significant soft tissue disruption. This study compares clinical and radiographic outcomes between a minimally invasive deltoid-split (MIS-DS) approach without allograft and the traditional deltopectoral approach with allograft.

Methods: We conducted a single-center, retrospective case-control study of 171 patients with unstable Neer's 3- and 4-part PHFs treated from January 2016 to July 2021. Patients were divided into two groups: the MIS-DS approach without allograft (n=90) and the deltopectoral approach with structural allograft (n=81). Outcome measures included range of motion (ROM), Constant-Murley (C-M), ASES, QuickDASH scores, and radiographic evaluations for fracture union, varus collapse, and screw perforation over a mean follow-up of 29.0 ± 2.4 months.

Results: Clinical outcomes, including C-M and ASES scores, ROM, and QuickDASH, were comparable between the two groups. Radiographic assessments showed an avascular necrosis rate of 6.4%, varus collapse of 11.1%, and screw perforation of 8.8% across both cohorts. The allograft group demonstrated a shorter mean surgical time, though reoperation rates did not significantly differ.

Conclusion: The MIS-DS approach, which emphasizes soft tissue preservation, achieves clinical and radiographic outcomes comparable to those of the deltopectoral approach with structural allograft augmentation in treating unstable PHFs. Given the similar outcomes between these techniques, surgeons may choose the approach they are most comfortable with, based on their expertise and the specific needs of the patient. Further prospective studies are recommended to validate these findings across larger populations.