The PHILOS plate for proximal humeral fractures--risk factors for complications at one year.

BACKGROUND Since 2003, we have used the Proximal Humerus Interlocking System plate for treatment of proximal humeral fractures. Although many patients have good and excellent results, the reported rate of complications varies. We have focused on the complication rate and risk factors for complications 1 year after surgery. METHODS From 2003 until 2008, a total of 294 (223 women; 71 men; median age, 72.9) patients were included. General data were collected at the time of injury (Charlson Index, smoking, and steroid therapy). Fractures were classified (AO/OTA) retrospectively. The follow-up of 1 year included radiographs and Constant-Murley score for functionality. Complications and revision surgeries were analyzed specifically. RESULTS We found 83 (28.2%) patients with a total of 105 complications, requiring a total of 72 (24.5%) revision surgeries. The most frequent complication was screw cutout (33 of 294, 11.2%), because of secondary fracture displacement or avascular necrosis (AVN). AVN (20 of 294, 6.8%) was the main reason for secondary arthroplasty. Smoking more than 20 pack years had a significant impact on the complication rate. Fractures classified 11-A3 showed more implant failures. Fracture dislocations predisposed to secondary screw cutout and AVN. Patients without complications (211, 71.8%) achieved a median Constant-Murley score of 89 (40-100) points. CONCLUSION This study points out several predisposing factors for negative outcome after open reduction and internal fixation with the Proximal Humerus Interlocking System plate (fracture type: 11-A3, fracture dislocations, and smoking). Accounting for these, patient's risk for complications can be evaluated more individually and taken into consideration for the concept of treatment. Altering the surgical technique was associated with a significant reduction in the incidence of secondary screw cutout.