Background: The hip center of rotation is an important landmark in performing total hip replacement and its restoration is one of the goals of the reconstruction. Several studies have attempted to locate the hCOR using radiographic landmarks. However, most of these methods were done on the Western population and only a few on Asian populations. Racial variations may influence the hip and pelvis morphometry and the hCOR. This may also have implications on the outcome of total hip arthroplasty. Thus, standardized values for Filipinos must be determined. 

Methods: One hundred forty-three pelvic AP radiographs were reviewed. The hip and pelvic morphometric values as well as the hCOR were measured and expressed in unit millimeter. The anatomic hCOR was determined using the concentric circle method and was compared to the hCORs, as determined by three frequently used methods: Ranawat’s, Pierchon’s, and Fessy’s. Descriptive statistics, Pearson’s correlation, and paired t-test were used for data analysis.

Results: The mean HD, VD, and FO for Filipinos were 33.2 ± 3.9mm, 17.0 ± 2.7mm, 37.6 ± 5.1mm, respectively. The mean values for males were 31.2 ± 3.3mm, 17.8 ± 2.6mm, and 38.8 ± 5.6mm, respectively. The mean values for females were 31.3 ± 3.3mm, 16.4 ± 2.6mm, and 36.8 ± 4.5 mm, respectively. Amongst the different methods used to determine the hCOR, the Pierchon’s method was found to be the most reliable for Filipinos. Pelvic height was found to have positive correlation with the horizontal distance, and ilium height-teardrop edge had positive correlation with vertical distance.

Conclusion: The pelvic teardrop is a reliable landmark for the determination of the hCOR. The average values of HD, VD, and, FO of Filipinos were comparable with studies on Asian populations. The Pierchon’s method is the most reliable in determining the hCOR of Filipinos.