LAUSR

BACKGROUND Intramedullary nailing is already established technique for the treatment of two and three-part fractures of proximal humerus. The aim of the study was to prospectively evaluate the efficacy and functional outcome after treatment of four-part fractures of proximal humerus with Multiloc proximal humeral nail. DESIGN prospective monocentric cohort study. SETTING single level 1 traumacenter. MATERIALS AND METHODS From February 2011 to March 2016, 40 patients with displaced four-part proximal humeral fractures were treated with intramedullary nail inserted through anterolateral approach. Minimum one year follow up completed 35 patients and were involved into the study. RESULTS After mean follow up period of 25.8 months 29 of 35 fractures healed. Average absolute Constant score in all 35 patients reached 57.7 points, relative side related Constants score 66.8% of contralateral extremity. Together there were 20 complications. in 6 cases (17%) developed complete avascular necrosis of the head. One deep infection was treated by implantation of antibiotic cement discs. Twelve secondary surgeries were performed, mostly for avascular necrosis development. Function and pain were significantly influenced by the quality of fracture reduction (p < 0.05) and development of complete AVN (p = 0.001). Group of 29 patients without AVN reached relative Constant score 73% of contralateral extremity. CONCLUSIONS Intramedullary nailing can be used as possible fixation technique for the treatment of four-part fractures of proximal humerus. In experienced hands provides nailing osteosynthesis similar results as reconstruction with locking plates. Appropriate reduction of fracture fragments is the key for good functional result. LEVEL OF EVIDENCE Level 2b - monocentric prospective cohort study.