Proximal Humerus Fractures Treated with Proximal Humerus Inter Locking System (PHILOS): Minimum 10-Year Clinical and Radiological Outcomes

Abstract

The long-term outcomes of open reduction and internal fixation with anatomical locking plates for proximal humerus fractures (PHFs) remain under-reported. Most literature has focused on short- to mid-term results, with limited data beyond a decade. This study aimed to evaluate the clinical and radiological outcomes at a minimum of 10 years postoperatively, in a consecutive series managed with a standardized surgical technique. Methods: From 2006 to 2015, 120 patients with PHFs were treated with open reduction and internal fixation using Proximal Humerus Inter Locking System by a single surgeon. At final review (mean follow-up, 14.9 years), 49 shoulders (in 48 patients) were available for full clinical and radiographic evaluation. Functional outcomes were assessed using the normalized Constant Score and Subjective Shoulder Value. Radiographic analysis included neck-shaft angle, osteoarthritis grade, avascular necrosis (AVN), and implant-related complications. Results: The mean normalized Constant Score was 88.7 and the mean Subjective Shoulder Value was 89.7. Mean elevation and external rotation were 149.5° and 52.9°, respectively. Strength in elevation and external rotation was significantly lower compared to the contralateral side (P < .001). High-grade osteoarthritis (grades 3–4) was observed in 8 shoulders (16%), with AVN identified in 6 of those. The overall complication rate was 26.5%, with AVN being the most common (12.2%). Screw penetration occurred in 6 shoulders (12.2%), primarily secondary to AVN or varus collapse. No infections or nonunions were recorded. The reoperation rate was 12.2%, all within the first 2 years postoperatively. No patient required revision arthroplasty during follow-up. Conclusions: Locking plate fixation for PHFs provides favorable long-term results, with low reoperation rates and acceptable functional outcomes. Despite limitations in external rotation strength and a 16% rate of high-grade osteoarthritis, most patients reported high satisfaction. These findings support the use of anatomical locking plates as a durable option for selected proximal humerus fractures, particularly when internal fixation is clearly indicated as the preferred treatment approach.