Evaluation of a one-stage ACL revision Technique using bone void filler after cyclic loading

Abstract

BackgroundRevision anterior cruciate ligament (ACL) reconstruction often requires a two-stage approach. This study analyzes the biomechanical properties after cyclic loading of a one-stage ACL revision technique using a calcium phosphate bone cement. MethodsArthroscopic reconstruction of the ACL was performed in 5 matched pairs of fresh–frozen cadaveric knees separated into two groups. The control group underwent a standard reconstruction with a bone-patellar tendon–bone autograft with bioabsorbable interference screw fixation. The experimental group simulated a failed reconstruction by drilling a 12mm hole and underwent a revision after filling it with a bioabsorbable calcium phosphate bone cement. The specimens were dissected, scanned for bone mineral density, and cyclically loaded on a mechanical testing system (preload of 250cycles of 5–75N at 0.5Hz followed by 10,000cycles of 20–150N at 1Hz). Intact specifmens underwent a load-to-failure protocol of 50mm/min. Ultimate load, stiffness, and modes of failure were recorded. Data was analyzed using paired t-tests. FindingsAll specimens completed the mechanical testing protocol. The control group had a mean maximum load of 471.33N (SD 220.73N) and the experimental group had 453.54N (SD 152.36; p=0.84). There were no statistically significant differences in maximum load or stiffness. No correlation between bone mineral density (BMD) and maximum load was found. InterpretationUsing calcium phosphate filler in a single-stage ACL revision is biomechanically viable. Further testing of long-term incorporation of the ACL graft in an animal model, along with human clinical trials, should be performed before there is clinical acceptance of this technique.