Modified use of a proximal humeral internal locking system (PHILOS) plate in extra-articular distal-third diaphyseal humeral fractures

Background: Surgical treatment of extra-articular distal-third diaphyseal humeral fractures is controversial in terms of surgical approach and position of implant. The aim of this study is to evaluate the clinical and radiological outcomes of a modified application of the proximal humeral internal locking system (PHILOS) plate in extra-articular distal-third diaphyseal humeral fractures. Materials and methods: A total of 23 patients with extra-articular distal humerus fractures were treated using either open plating or the minimally invasive plate osteosynthesis (MIPO) technique with upside down application of the PHILOS plate. Fracture configuration, number of screws in the distal fragment, and time to union were analysed. Elbow range of motion, Mayo Elbow Performance Score (MEPS), and complications were evaluated at the final follow-up. Results: Fracture union was obtained in all patients at a mean postoperative time of 20.8 ± 2.9 weeks. The mean shortest and longest cortical lengths were 50.7 ± 14.0 mm and 85.2 ± 12.4 mm, respectively. The average number of screws in the distal humeral fragment was 5.6 ± 0.7. No statistically significant correlation was observed between the shortest cortical length and number of screws in the distal fragment (p = 0.224) or between the longest cortical length and the number of screws in the distal humeral fragment (p = 0.956). The average MEPS was 97.6 (range, 75–100). No postoperative complications that required reoperation were occured. Conclusion: A modified anterior application of the PHILOS plate in extra-articular distal-third diaphyseal humeral fracture showed satisfactory outcomes, so it is an alternative when considering the ability to increase plate-screw density with locking screw fixation in a distal humeral fragment. Level of evidence: Therapeutic level IV, case series.