The Effect of Prophylactic Cerclage Wires in Primary Total Hip Arthroplasty: A Biomechanical Study.

BACKGROUND: Despite literature to support the use of various cerclage techniques to address intraoperative femoral fractures in total hip arthroplasty, there are limited data to support prophylactic cerclage wiring of the femur during cementless implant placement. This study aims to evaluate the effect of prophylactic calcar cerclage wires on the biomechanical parameters required to produce periprosthetic femoral fractures and on the morphology of these fracture patterns in stable cementless femoral implants. METHODS: Ten pairs of matched fresh frozen cadaveric femurs were implanted with anatomic tapered cementless implants with or without the addition of 2 monofilament calcar wires. Specimens were axially loaded and externally rotated to failure. Initial torsional stiffness, rotation and energy to failure, and torque at failure were measured. Statistical significance was set at P < .05. Fracture patterns were classified according to a well-known classification system. RESULTS: Wired specimens required significantly more rotation (P = .039) and energy to failure (P = .048). No significant difference was detected in initial torsional stiffness (P = .63) or torque at failure (P = .10). All unwired samples developed a Vancouver B2 fracture pattern. Seven of the 8 wired specimens also developed a Vancouver B2 fracture pattern, while the eighth wired specimen developed a Vancouver B1 fracture pattern. CONCLUSION: Prophylactic cerclage wire placement increases the rotation and energy to failure in well-fixed press-fit femoral implants. The increase in torsional energy needed for failure may reduce the risk of early periprosthetic fracture. Further studies are needed to evaluate cost vs benefit and long-term outcomes of prophylactic wiring. Based on the results of our study, consideration of prophylactic wiring should be addressed on a case-to-case basis.