Biomechanical evaluation of cemented femoral stem constructs with single and double cerclage stabilization of proximal fissures in canine cadaveric femora.

Proximal femoral fissures are among the most frequently encountered intraoperative complications during cemented total hip replacement (THR) in dogs; because cement polymerization cannot be interrupted once initiated, surgeons must stabilize the fissure immediately to prevent progression to a complete fracture. Although cerclage wiring is routinely recommended, the comparative mechanical behavior of different cerclage configurations in cemented femoral stem constructs remains poorly defined. This biomechanical study evaluated the effects of single- and double-loop stainless-steel cerclage wiring on the stability of cemented femoral stem constructs with a standardized proximal metaphyseal fissure in German Shepherd Dogs (GSDs) and Labrador Retrievers (LABs) and compared their performance with intact constructs under axial compression, three-point bending, and axial torsion. Fifty-four femora (n = 6 per group per breed) were implanted with cemented femoral stems and allocated to intact, single-loop, or double-loop configurations before undergoing destructive mechanical testing. Outcome measures included stiffness, yield load, maximum load, deformation characteristics, energy absorption, torque, and torsional strength. Data were analyzed using a general linear model incorporating breed, group, and breed × group effects, followed by Tukey and Bonferroni post-hoc comparisons. Intact constructs demonstrated the highest overall mechanical performance across all tests. Among fissure-stabilized constructs, double-loop cerclage consistently outperformed single-loop fixation, showing superior axial, bending, and torsional resistance, higher failure loads, and enhanced deformation tolerance. Single-loop constructs provided partial reinforcement but remained mechanically inferior to double-loop fixation in both breeds. Breed-related differences were observed, with GSD femora exhibiting higher absolute strength and LAB femora showing greater deformation capacity; however, no Breed × Group interaction altered the mechanical superiority of double-loop cerclage. These findings indicate that double-loop cerclage provides the most reliable reinforcement strategy for stabilizing proximal femoral fissures during cemented THR. Although intact constructs remain biomechanically superior, double-loop cerclage offers meaningful intraoperative protection against fissure propagation and supports improved implant stability. Further investigations incorporating cyclic loading and larger sample sizes are warranted to optimize clinical recommendations.