A radiographic and anatomic study of caudolateral curvilinear osteophytes on the canine femoral neck

Caudolateral curvilinear osteophytes (CCOs) are considered to be an important finding for the early detection of canine hip dysplasia. The objective of this study was to determine the association between the radiographic and anatomic appearance of CCOs, and to determine whether CCOs are indicative of osteoarthritis. One hundred canine femurs were used to determine the topographical location of CCOs on the femoral neck, and the anatomic and radiographic presence of CCOs and their association with weight, sex, osteoarthritis, and femoral morphometry. Three angles were calculated to assess femoral conformation. The alpha angle and gamma angle described the angulation of the proximal femur and femoral neck, respectively. The beta angle described the angulation of the distal femur. Anatomic CCO was not detected in four femurs. No radiographic CCO was detected in 35 femurs and osteoarthritis changes were not found in 30 femurs. Statistically significant relationships were observed between anatomic CCO, alpha angle, and gamma angle. Statistically significant associations were observed between radiographic CCO, alpha angle, and gamma angle. The results of this study support an association between radiographic CCO on the femoral neck and osteoarthritis changes in the proximal femur. It can also be concluded that CCOs develop in association with femoral neck angulation, and may therefore be considered as an adaptation to the forces created by body weight that act through the femoral neck.