Minimally invasive plate osteosynthesis in proximal humeral fractures: one-year results of a prospective multicenter study

Purpose: The aim of this multicentric study was to evaluate results of minimally invasive plate osteosynthesis (MIPO) for proximal humeral fractures in terms of postoperative shoulder function, radiological outcome and number of complications. Methods: A consecutive series of 76 patients with proximal humeral fractures were treated with locking plate using a minimally invasive antero-lateral approach in two orthopaedic departments. Functional results with Constant score and radiographic evaluation were available for 74 patients at one-year follow up. Results: The patients achieved a mean Constant score of 71 (range 28–100). Each functional result was evaluated also for both centres without significant differences. Significant statistical differences were only found for younger patients with better results (p < 0.05). Twenty patients (27 %) developed complications. Subacromial impingement occurred in 16.2 % of cases for varus malreduction (6.7 %) and for too proximal plate positioning (9.5 %). Primary screws perforation (2.7 %), secondary perforation due to cut-out (1.4 %), avascular necrosis (AVN) of humeral head (1.4 %), partial resorption of greater tuberosity (2.7 %), secondary dislocation of the greater tuberosity (2.7 %) and stiffness (2.7 %) were the other complications observed. Conclusions: The MIPO technique for proximal humeral fractures was safe and reproducible for most common patterns of fracture. Major complication rate was apparently low due to a soft tissue sparing, deltoid muscle and circumflex vessels, with easy access of the bar area to correct positioning of the plate.