ObjectiveThe purpose of this study is to determine the efficacy of the open reduction and fixation of a dislocated proximal humerus fracture with a locking plate, also evaluating the incidence of complications and functional recovery of the shoulder. A retrospective study focusing on patients who had suffered a fracture of the proximal humerus and were treated by means of an open reduction and internal fixation with a locking plate, using either the Philos or the LPHP plate. We have also included a comparison of these two plates.MethodNinety-two patients were found to be eligible and were included in our study. These patients had all been treated for a proximal humerus fracture between 2002 and 2008. We included those patients who could be classified as a class 2, 3, or 4 according to the Neer classification. Demographic data, surgical technique, and peri/post-operative complications were collected from medical records. Patients were followed-up and the Oxford Shoulder Score (OSS) was filled in by phone. The mean age of our patient population was 66.2 (15–97), with a male: female ratio of 1:5 (15:77). (The median follow-up was 2.4 years (0.2–5.8). Fourteen of our patients died during follow-up, while 25 patients were otherwise lost to follow-up. For this study, out of the original 131 patients, this finally resulted in 92 patients whom we followed-up post-operatively.ResultsNinety-two patients (70%, 92/131) were interviewed. The mean Oxford Shoulder Score (OSS) was 19.76 (11–54). The overall complication rate was 39.1% (36/92). The most frequently occurring complications in our patient population were hemorrhage 3.3%; dislocation of the caput humeri and/or tuberculum majus 2.2%; persistent pain 3.3%; Avascular necrosis (AVN) of the humeral head 0%; Loss of reduction and screw cutout 6.5%; Plate breakout 6.5%; Subacromial Impingement 11.9%; Frozen shoulder 3.3%; rotator cuff rupture 1.1%, and infection 1.1%. Of the entire group of patients originally included in this study, 29% was re-operated due to one of the above-mentioned complications.ConclusionIn conclusion, the locking plate provides satisfactory functional outcomes after a mid-term follow-up in patients with displaced proximal humerus fractures. The incidence of complications and subsequent re-operation is relatively high, however, comparable to or slightly better when compared to data found in literature. Subacromial Impingement seems to occur more frequently when a Philos plate is implemented. We therefore suggest that randomized clinical trials determining the possible superiority of one specific type of plate in patients with a displaced proximal humerus fracture are to be performed in future.