Evaluation of the instantaneous centers of rotation of the stifle before and after repair of torn cruciate ligament by use of the over-the-top technique in dogs

Seven dogs with torn cruciate ligament were used to evaluate the "over-the-top" repair procedure, using instantaneous center of rotation (ICR). Normal and cruciate-torn stifles of dogs were radiographed before surgery, using an image intensifier videotape system. The injured stifle was reradiographed 6 weeks after surgery. Images of the stifles were photographed from video monitor. Photographs were analyzed by a digitizer hooked to a computer to find the ICR at various angles. Data were analyzed, using multivariate analysis of variance. Relative to those of normal stifles, ICR of the damaged stifles were located significantly (P less than 0.05) proximal and caudal. After surgery, the ICR were still proximal and caudal, but not significantly so. We conclude that the cruciate-torn stifle deviates significantly from normal and that such deviation is restored to normal limits by use of the over-the-top procedure.