GENDER SPECIFIC ANATOMY OF THE DISTAL FEMUR

Abstract

Introduction: morphological analysis of the general shape of the bones and of their particular variations according to the patient age, gender and pathology is an important step to improve the orthopedic management. We aimed to performed a gender specific analysis of the bi and tridimensional anatomy of the distal femur in vitro and in vivo.

Materials and Methods: in vitro data were obtained from CT-scan performed on 92 dry men femurs and 52 dry women femurs. Using a manual contouring method and a segmentation method, tridimensional reconstructions were obtained and according to two different algorithms, the regions of discrepancies between men and women were determined. An automatic calculation of 59 defined measurements was then performed. In vivo data providing from 59 CT-scans of men femur and 73 CT-scan of women femurs were acquired. Standardized bidimensional measurements at the level of the trochlear cut were performed.

Results: in vivo, statistically significant differences were observed for the: medio-lateral distance (M-Ld women=7.4±0.4cm vs M-Ld men=8.4±0.5cm; p< 0.0001), anteroposterior distance (A-Pd women=5.9±0,4cm vs A-Pd men= 6.4±0.4cm; p< 0.0001) and for the ratio anterior-posterior distance/medio-lateral distance (p< 0.0001). The trochlear groove angle was comparable in the two groups. In vitro, the tridimensional shape of the distal femur was more trapezoidal in women than in men. Medio-lateral distances were also statistically greater in men than in women (p< 0.01), the ratio anterior-posterior distance/medio-lateral distance was also statistically greater in men than in women (p< 0.01) and the Q angle more open in women than in men (p< 0.01).

Discussion: Three types of differences between men and women were observed in this gender specific evaluation of the distal femur anatomy. First, for a same anteroposterior distance, the medio-lateral distance was smaller in women. Second, the global shape of the distal femur was more trapezoidal in women and third the Q angle was more open in women. This gender specific anatomy should be clinically considered when performing total knee arthroplasty in women and gender specific implants may be required.