Comparative study of sex differences in distal femur morphology in osteoarthritic knees in a Chinese population

Abstract

Objectives: The purpose of this study was to investigate sex differences in resected distal femoral morphology in Chinese osteoarthritic knees.

Methods: The study included 130 osteoarthritic knees in 65 men and 65 women in China. None had anterior femoral osteophyte or serious patellar femoral joint degeneration. The following were measured using computed tomography and analyzed to identify morphological differences according to sex in the resected distal femurs: anterior lateral condylar height (ALCH), anterior medial condylar height (AMCH), and mediolateral (ML) and anteroposterior (AP) dimensions. The ML/AP aspect ratio was calculated.

Results: The average ALCH and AMCH were 8.2±1.8 mm, 3.1±1.5 mm for men and 7.4±1.7 mm, 3.6±1.5 mm for women. There were significant differences between men and women in ALCH values (P = 0.014) but not in AMCH values (P = 0.09). Women had smaller ML/AP aspect ratios than men for a given AP dimension. This indicated that the femoral ML dimension of a prosthesis with a given AP dimension may have overhang in women.

Conclusions: This study suggested that sex differences should be taken into account in the design of femoral prosthesis for Chinese men and women.

Figure 1. Cuts and measurements of the distal femur on computed tomography (CT) images.

(A) A coronal CT image of a femur. The red line indicates the distal femur cut line. (B) A sagittal CT image of a femur. The red line indicates the anterior condyle cut line, which is flush with the anterior femoral cortex. (C) An axial CT image shows the measurement parameters for the distal femur. The red line indicates the anterior condyle cut line.

Figure 2. The ML dimensions were plotted against the AP dimensions for men and women.

Figure 3. The ML/AP aspect ratios were plotted against the AP dimension for men and women.