Average Tibial Plateau Angle of 3,922 Stifles Undergoing Surgical Stabilization for Cranial Cruciate Ligament Rupture

The aim of this study was to report the average tibial plateau angle (TPA) from a large sample of dogs and to determine if breed or gonadectomy had a significant association with abnormal TPA.

This was a retrospective case study.

Medical records from 2006 to 2015 were reviewed for dogs that were diagnosed with cranial cruciate ligament (CrCL) rupture and underwent dynamic surgical stabilization. Signalment, examination findings, preoperative TPA and surgical report were reviewed.

A total of 3,249 dogs underwent CrCL stabilization surgery from 2006 to 2015. Of the 3,249 dogs, 3,054 dogs met the inclusion criteria for a total of 3,922 stifles to be evaluated. The average preoperative TPA was 29° ± 3.7°. Average breed-specific preoperative TPA ranged from 27° to 35.1°, with four breeds having significantly lesser TPA and four breeds significantly greater TPA than the overall mean of dogs. Neutered dogs had a higher TPA of 28.87° ± 3.8° than non-neutered dogs with an average TPA of 26.88° ± 4.0°, p < 0.001. There was not a significant difference in average TPA between females and males, regardless of the neuter status.

Our reported preoperative TPA in a large sample of dogs is higher than what has been previously published. In reviewing 3,922 stifles, the average preoperative TPA was 29°. We report the average preoperative TPA in specific breeds and report that neutered dogs have a significantly higher TPA than intact dogs. This updated information may guide clinicians in management decisions regarding treatment for CrCL rupture.