Effect of 9 mm Tibial Tuberosity Advancement on Cranial Tibial Translation in the Canine Cranial Cruciate Ligament Deficient Stifle

Abstract

Objective-To assess the effect of 9 mm tibial tuberosity advancement (TTA) on cranial tibial translation (CTT) in cranial cruciate ligament (CCL) deficient canine stifles.

Study Design-In vitro cadaveric study.

Animals-Twelve canine pelvic limbs.

Methods-Each stifle was placed in a jig at 135° with a simulated quadriceps force and tibial axial force, and the distance of CTT was measured with the CCL intact (iCCL), transected (tCCL), and after performing a TTA using a 9 mm cage. In addition, a material testing machine was used to assess the force required to elicit CTT in each scenario.

Results-The mean CTT for iCCL was 0.42 mm, 1.58 mm after severing the CCL, and 1.06 mm post TTA. The tCCL CTT measured without any quadriceps force was 2.59 mm. Differences between the intact and tCCL (p<0.0001) and tCCL and TTA (p=0.0003) were significant. The difference between the tCCL with and without the quadriceps force was not significant (p=0.0597). The force required to cause CTT was greater in the TTA than the tCCL up to 6mm (p<0.0001). As axial load increased, the force required to advance the tibia increased in both treatment groups (p value for overall weight effect =0.0002).

Conclusions- These data confirm that TTA does reduce CTT in tCCL stifles in this model. The addition of a simulated quadriceps force to a CCL deficient stifle prior to a TTA, by itself, may not significantly lessen CTT.

Clinical Relevance- While this in vitro model demonstrated that TTA reduced CTT in canine stifles with CCL transected, the modular limitations preclude extrapolation to the effect of TTA on the live dog.