[Morphological analysis of the proximal femur by computed tomography in Japanese subjects]

In order to evaluate the morphological features of the proximal femur in the Japanese, 100 femora of normal Japanese subjects (normal group) and 60 femora of 43 Japanese patients with secondary osteoarthrosis of the hip (OA group) were analyzed using CT images. The scans for the dried bones (normal group) were done at a setting of 80 kV and 20 mA, for 2 sec duration. The scans were reconstructed using the soft tissue algorithm built into the GE-9800 scanner. The patient scans (OA group) were done at 120 kV and 170 mA also for 2 sec duration, and reconstructed using the same bone algorithm. The results were as follows: 1) Thinning of the femoral cortex occurred in normal females over 60 years of age. 2) The canal flare index at the proximal part of the femoral diaphysis was negatively correlated with the canal diameter at the isthmus. The index at the upper part was greater than that at the lower part. The two groups showed no statistical difference in this index. 3) In the metaphysis, the canal flare index at the anterior portion was twice that at the posterior portion. In absolute terms, the OA group had a reduced flare or curve along the medial portion. 4) In cross-section, the canal shape of the diaphysis was more elliptical in the OA group than in the normal group. The longitudinal axis of the canal was directed more sagittally in the OA group than in the normal group.