Effect of conformation of the distal portion of the femur and proximal portion of the tibia on the pathogenesis of cranial cruciate ligament disease in dogs

To evaluate mediolateral radiographic views of stifle joints to identify conformational differences between athletically sound dogs and dogs with cranial cruciate ligament disease (CCLD). Radiographic images of 50 stifle joints of 43 dogs with surgically confirmed CCLD and 50 stifle joints of 38 dogs without clinical signs of stifle joint disease. Mediolateral radiographic views of stifle joints were obtained, and long axes of the femur, tibia, and femoral condyles were measured. Angles between long axes of the femur and femoral condyle and between long axes of the femur and tibia were measured. Circles were drawn representing the joint surface of femoral condyles (circle 1), area of contact on the tibial plateau (circle 2), and femoral trochlea (circle 3). Radii of circles 1, 2 (line F), and 3 were measured. Distances between midpoints of circles 1 and 2 (line K) and between midpoint of circle 2 and most cranial aspect of the tibial tuberosity (line G) were measured. To evaluate differences in conformation that could lead to CCLD, quotients derived from measurements were created for comparison; angles were compared between dog groups. Significant differences were found in the quotients created by the lengths of lines G and F and lines G and K between dogs with and without CCLD. No anatomic differences were detected in the distal portion of the femur between dogs with and without CCLD. Development of the tibial tuberosity and shape (convexity) of tibial condyles may be relevant in the pathogenesis of CCLD.