Evaluation of proximal femoral geometry using digital photographs

Abstract

The morphologic features of the proximal femur are used in preoperative planning prior to total hip arthroplasty. Recent literature evaluating the anatomy of the proximal femur, as it relates to total hip arthroplasty, has relied heavily on radiographs or computed tomography. We used digital photographs to compare 200 cadaveric femora in individuals who died prior to 40 years of age: 25 African-American males, 25 African-American females, 25 Caucasian males, 25 Caucasian females. With our technique and definition, the actual angles and dimensions of the proximal femur that we normally rely on during total hip arthroplasty were measured. There were small, but statistically significant differences, between males and females in neck-shaft angle, neck inclination, and absolute horizontal and vertical offset. Females tended to have a lower neck-shaft angle and more neck inclination. When standardizing the offset distances with femoral head diameter, the horizontal offset ratio was higher in female specimens. There was no correlation between horizontal and vertical offset. Improved knowledge of the morphology of the proximal femora will assist the surgeon in restoring the geometry of the proximal femur during total hip arthroplasty. This information also supports the concept of modularity of the femoral neck in order to independently adjust neck-shaft angle, neck inclination, and horizontal offset.