Three-dimensional acetabular morphology of chinese population: A Computed Tomography– based study

Abstract

Introduction: Acetabular morphology plays an important role in the development of various hip pathologies and the design for total hip arthroplasty prostheses. We studied the three-dimensional acetabular morphology in a Chinese population and compared our results with existing data from Caucasian populations. Methods: Volumetric computed tomography pelvis data of 57 individuals (24 male, 33 female) without hip symptoms were utilised for three-dimensional construction. Acetabular sphere was established. Intersection arcs of 35 planes and acetabular sphere were defined. Angles of the arcs uncovered by the acetabulum were measured. Such angles reflect the morphological features of acetabular rim. The most prominent and depressive part of acetabular rim can be represented as the smallest and largest angle. Results: All angles of the arc uncovered by the acetabulum were >90°, meaning the Chinese acetabulum is a subhemispherical structure. The acetabular rim has three prominences and two depressions. The peak of the anterosuperior prominence is located at 58.3°, the peak of the anteroinferior prominence is located at 139°, the peak of the posteroinferior prominences is located at 234.3°, the peak of the anterior depression is located at 102.3°, and the peak of the posterior depression is located at 323.1°. There were no significant difference between male and female acetabula (p>0.05). When compared with the Caucasian data, Chinese acetabula are smaller and shallower. Conclusion: The complex geometry of the concave acetabulum benefits from three-dimensional visualisation and quantification. A shallow acetabulum may be the cause of low incidence of pincer-type femoroacetabular impingement and primary osteoarthritis. It may also call for the need of special Asian prostheses in total hip arthroplasty.