Clinical outcomes of retrograde intramedullary multiple pinning for proximal humeral fractures using a modified palm tree technique

Retrograde intramedullary multiple pinning using a modified palm tree technique for proximal humeral fractures has attracted interest from surgeons because of its minimal invasiveness into the soft tissue around the shoulder joints. We aimed to evaluate the clinical and radiological outcomes of this procedure. This retrospective study included 21 patients who underwent surgery using a modified palm tree technique for proximal humeral fractures between March 2010 and March 2022. Patients with two- and three-part proximal humeral fractures that could be reduced by closed manipulation under general anesthesia were included in this study. All patients were clinically evaluated using the Japanese Orthopaedic Association (JOA) and University of California at Los Angeles (UCLA) shoulder scores. Postoperative radiographic findings, including fracture healing and signs of pinning-related complications, were evaluated. Twenty-one shoulders in 21 patients (9 men and 12 women) with mean age at surgery of 66.3 ± 19.3 years were evaluated. The mean period until bone union was 2.6 ± 0.7 months. The mean JOA and UCLA shoulder scores at the final follow-up were 84.8 ± 12.1 and 27.5 ± 5.4, respectively. Perforation of the humeral head by Kirschner (K) wires was observed in 9 of the 21 (42.9 %) shoulders. The JOA and UCLA shoulder scores at the final follow-up were not significantly different between the groups with and without perforations (p = 0.41 and 0.27, respectively). The oblique or Y-view detected significantly more wires with perforation of the humeral head than did the anteroposterior view (6 vs. 15 wires, p