Impact of CT-based 3D modelling on hip joint anatomical measurements: a comparative study with 2D methods

The functionality of the hip joint is primarily determined by the anatomical relationship between acetabulum and femur. Impairment of this relationship can lead to diseases such as femoroacetabular impingement and hip osteoarthritis. In patients undergoing total hip arthroplasty, accurate placement of the acetabular and femoral components in accordance with native 3-dimensional anatomy (3D) is crucial for obtaining prosthesis stability and survival, also for preventing postoperative complications such as wear, dislocation and osteolysis. Therefore, 3D determination of native anatomical features of the hip joint is highly important.

A total of 100 adults were randomly selected. Right femur and acetabulum were segmented using MIMICS program. 2D and 3D measurements of femoral anteversion according to posterior condylar and transepicondylar axis, acetabular anteversion, acetabular inclination and combined anteversion were determined. The differences between gender groups and the correlations of two- and three-dimensional measurement results were evaluated.

According to 2D and 3D measurements, statistically significant differences were observed between gender groups in all parameters except for 2D acetabular inclination. A very strong correlation was observed between 3D femoral anteversion measurements performed using the posterior condylar axis and transepicondylar axis. Our findings revealed statistically significant differences between 2D and 3D measurements in most parameters, which have clinical relevance.

A very strong correlation between femoral anteversion measurements obtained using the transepicondylar and posterior condylar axes supports the intraoperative use of the transepicondylar axis reliably. We believe the data obtained from our study will contribute to understand the 3-dimensional native anatomy of the hip joint.