The aim of this preliminary study was to determine the accuracy of CT-scan to locate the femoral head centre. METHODS: Eleven dried femurs were included for study. Three techniques were compared to determine femoral head centre (FHC) location: CT-scan, Motion Analysis and Faro-Arm. Markers were stuck on each femur to create a system of coordinates. Femurs lied on their posterior parts (bicondylar plane). Several points around the femoral head were palpated (Motion Analysis and Faro-Arm) or determined (Amira software for CT-scans). By a least-square regression method, the FHC location in 3D was defined for each technique. RESULTS: The results of the FHC location determined by the CT-scan technique were compared with those measured by the faro-arm and the Motion Analysis techniques. The coordinates (X, Y, Z) of the FHC were compared between the three methods, and no statistical difference was found (p = 0.99). In a 3D plot, this gave a mean difference of 1.3 mm. The mean radius of the femoral head was of 22.5 mm (p = 0.6). CONCLUSIONS: CT-scan is as accurate and reliable as gold-standard techniques (motion and faro-arm). Locating FHC before and after hip arthroplasty would allow hip surgeons to determine and compare 3D orientation of the upper-end of femur: offset, height and anteversion.
