Effects of the Ruby Procedure on Stifle Stability in an Ex-vivo, Cadaveric Model

Introduction: The Ruby procedure is an extracapsular repair method that aims to restore stifle stability using modified titanium alloy bone anchors with ultra-high molecular weight polyethylene fiber loops, and a titanium-alloy link. The primary objective of this study was to characterize the effect of the Ruby procedure on the stability of the cranial cruciate ligament (CrCL) deficient stifle. Secondary objectives were to compare the stability of the Ruby procedure to that of the CrCL-intact and CrCL-deficient stifle.

Materials and Methods: Each canine pelvic limb was mounted in a loading jig under 30% body weight. Motion data were collected using an electromagnetic tracking system at stifle angles of 125, 135, and 145 degrees with the CrCL-intact, CrCL-deficient and the Ruby applied.

Results: Increases were noted between the CrCL-deficient and the CrCL-intact stifles for total translation, internal–external rotation, varus–valgus, and flexion–extension at all angles. Total translation of the CrCL-deficient stifle following the Ruby procedure was reduced, but significantly different from the CrCL-intact stifle. Internal rotation of the CrCL-deficient stifle was reduced following the Ruby procedure and was significantly different between these conditions at 145 degrees.

Discussion/Conclusion: The Ruby procedure resisted total translation and internal rotation of the tibia relative to the femur in the CrCL-deficient stifle. Total translation and internal rotation of the CrCL-deficient stifle following the Ruby procedure closely approximated that of the CrCL-intact stifle.

Acknowledgment: The investigators of this study acknowledge KYON Veterinary Surgical Products for donating a portion of the materials for this study.