We assessed the possible association between an aggressive intercondylar notchplasty and histopathologic, radiographic, and gait changes to the knee. Three groups of six adult greyhounds were observed for 6 months. Group I dogs had a sham operation. Group II dogs had a 4-mm notchplasty of the lateral femoral condyle where it articulates with the lateral tibial spine. Group III dogs had a 7- to 8-mm notchplasty of the lateral femoral condyle to simulate the long-term effects of an overly aggressive notchplasty.