Histomorphometric analysis of the proximal portion of the femur in healthy dogs

Objective-To describe the cancellous bone architecture of the head and neck of the femur in healthy dogs by use of automated histomorphometry techniques in conjunction with histologic grading of articular cartilage. Animals-30 mature male dogs with healthy coxofemoral joints Procedure-Dogs were 1.5 to 4 years old and weighed 27 to 37 kg. Computer images of fine-detail radiographs of 100-mu m-thick coronal and transverse plane sections of the head and neck of the femur (14 dogs) were analyzed by use of histomorphometry software. Statistical comparisons among histomorphometric indices of 4 regions were performed. Histologic preparations of coronal and transverse plane sections of femoral head articular cartilage (16 dogs) were graded, Median grades for lateral, medial, cranial, and caudal halves of the femoral head articular cartilage were determined. Results-Bone volume/total volume, trabecular thickness and number, and bone surface/total volume were significantly higher in the femoral head than in the femoral neck. Anisotropy (trabecular alignment) and trabecular separation were significantly higher in the femoral neck than in the femoral head. Anisotropy was significantly higher in the caudal half of the femoral neck than in the cranial half. Cartilage had histologic grades indicating health without significant differences among lateral, medial, cranial, and caudal halves of femoral head cartilage. Conclusions and Clinical Relevance-A predictable cancellous architecture in the head and neck of the femur is associated with healthy cartilage.