B.A. Lewis, D.A. Allen, E.R. Wilson, T. Henrikson, T. Lehenbauer.
Mission MedVet, Mission, KS, United States, 2Oklahoma State University, Stillwater, OK, United States

ACVS Abstract 2007

Human and veterinary orthopedic literature has implicated intercondylar notch stenosis as a mechanical factor in cranial cruciate ligament rupture and intraarticular graft failure. Our study included 72 client owned dogs weighing greater than 10 kilograms with no other detected congenital or acquired stifle abnormalities. Dogs that participated in this study were classified as normal (32), unilateral cruciate rupture (23), or bilateral cruciate rupture (17). Dogs were placed under general anesthesia and had both stifles scanned via computed tomography as previously described.

Three slices at predetermined levels were evaluated within the notch. Measurements included opening notch angle, notch width and height, condyle width, and notch width index (notch width/condyle width) at two different heights within the notch. Intercondylar notch measurements at the most cranial extent were significantly more narrow in unilateral and bilaterally affected stifles when compared to the normal population.

Significant differences were noted in the opening notch angle, notch width index (NWI), and NWI at two thirds notch height. No significant differences were noted between unilateral and bilaterally affected stifles.  Increased mechanical contact of the cranial cruciate ligament with a stenotic intercondylar notch may predispose the ligament to mechanical wear and structural weakening. Intercondylar notch measurements have been used as a tool to predict risk of anterior cruciate ligament injury in young human athletes, and to assess risk factors for intraarticular graft replacements. Our findings may be useful in developing similar predictive models using stifle CT scans.