Comparison of CFR-PEEK and conventional titanium locking plates for proximal humeral fractures: a retrospective controlled study of patient outcomes

Background: Metal plates are the fixation devices used most frequently to proximal humeral fractures (PHFs). However, in recent years carbon fiber-reinforced polyetheretherketone (CFR-PEEK) plates have become increasingly common. This study compares the clinical and radiographic outcomes of 42 Neer three- and four-part PHFs treated with CFR-PEEK or metal (titanium) plates. Materials and methods: Forty-two PHF patients were managed with CFR-PEEK plates (n = 21, males/females 9/12; mean age 57.4 years; mean follow-up 30.7 months; CFR-PEEK group) or metal plates (n = 21; males/females 7/14; mean age 55.8 years; mean follow-up 52.7 months; Metal group). Active shoulder mobility (anterior elevation, lateral elevation, external rotation, and internal rotation), the Constant–Murley Score, the Simple Shoulder Test Score, and the pain score were recorded. Preoperative computed tomography scans and X-rays were obtained. Postoperative fracture healing and displacement, tuberosity resorption and/or malposition, hardware position, and cortical thinning (CT) under the plate were assessed radiographically. Results: Shoulder mobility, clinical, and pain scores were similar in both patient groups. CT was significantly greater in CFR-PEEK patients (mean difference, 1.14 mm; p = 0.0003). In both groups, incomplete or poor calcar reduction was associated to a significantly higher complication rate, especially stiffness and muscle weakness (p = 0.016). The rate of tuberosity resorption was significantly higher in the Metal group (p = 0.040). Two patients required revision to a hemiarthroplasty (CFR-PEEK) and reverse arthroplasty (Metal group). Conclusions: CFR-PEEK plates provide a viable alternative to conventional titanium plates in PHFs, ensuring similar clinical outcomes and a lower rate of tuberosity resorption, but they involve higher stress shielding under the plate.