Polymer-Based Cerclage Cables Are Equivalent to Stainless Steel Cables in Management of Peri-Isthmic Periprosthetic Femoral Fractures: A Biomechanical Comparison.

Background: Periprosthetic femoral fractures (PPFs) following total hip arthroplasty (THA) are challenging complications, and as THA is increasingly performed in younger, more active populations, the incidence of PPFs is expected to rise. Treatment often requires tapered titanium stems to provide axial and rotational stability, and cerclage fixation is commonly used. Traditional metallic cerclage cables are effective, but carry risks such as fretting, corrosion, and intraoperative injury. Polymer-based cerclage cables have emerged as an alternative, though biomechanical data comparing them to metallic cables is limited. This study aimed to compare the strength of metal versus polymer-based cerclage cables in the treatment of isthmic PPFs during revision THA with a tapered titanium stem.

Methods: A biomechanical study was performed using 20 fresh-frozen human cadaver femora (10 matched pairs). Femora were divided into two groups: one using stainless steel cables (stainless steel group) and the other using polymer-based cables (polymer group). The femora were osteotomized to simulate isthmic fractures and fixed with three cerclage cables per femur. The specimens underwent cyclic loading, stepwise loading, and loading to failure. Axial testing was performed using a servohydraulic material testing system, and primary outcomes included stem subsidence and vertical fracture displacement.

Results: Under cyclic fatigue loading at a 500 N force, there were no differences in subsidence (P = 0.19) or fracture displacement (P = 0.14) between the groups. Under stepwise loading to 2,600 N, subsidence (P = 0.23) and vertical fracture displacement (P = 0.22) were similar across both groups. When tested to failure, both groups also demonstrated similar forces required to cause subsidence greater than 10 mm (P = 0.27) and fracture displacement (P = 0.22).

Conclusions: Polymer-based cerclage cables provide biomechanical stability equivalent to metallic cables in the treatment of isthmic PPFs during revision THA and may reduce risks, such as corrosion and injury, associated with metallic cables. Further studies are needed to assess long-term outcomes.