The effect of tibial tuberosity advancement (TTA) on caudal cruciate ligament (CACL) rigidity in canine stifle joint under cranial femoral drawer. Comparison between intact, cranial cruciate ligament-deficient (CRCL-deficient) and TTA knee: An Ian in-vitro experimental study

Abstract

The tibial tuberosity advancement (TTA) is a surgical technique used to repair cranial cruciate ligament-deficient (CrCL-deficient) canine knees. The aim of this study was to assess the effect of TTA on caudal cruciate ligament (CaCL) under femoral anterior force, in a 135° joint extension angle; and the role of CaCL in an CrCLdeficient knee. Five fresh cadaveric adult canine stifle joints were tested in an apparatus in which muscle forces were simulated. Each knee was tested in three different conditions: intact, CrCLdeficient knee and with TTA surgery. Shear force (Newtons, N) and CaCL deformation (millimetres, mm) were measured using sensors and the ligament rigidity (force divided by deformation, N/mm) was calculated and compared between the three knees. The mean rigiditiy values increased from intact knee, 104.4 N/mm (SD 3.6), to CrCL-deficient knee, 136.5 N/mm (SD 7.5). However, the rigidity was even greater when applying the TTA, 257.2 N/ mm (SD 21.1). Since, stress on the CaCL in CrCL-deficient knees was greater than in intact knees, the ligament assumed a more important role. On the other hand, the TTA technique generates an overload on the CaCL until rigidity exceeds its load-bearing capacity. Although the in-vitro models are far from reality, these findings suggest the need to further study the effects of TTA on the CaCL.