Materials and Methods

141 anonymous Chinese femoral CT scans (71 male and 70 female) with mean age of 60.1years (range 20–93) and 508 anonymous Caucasian left femoral CT scans (with mean age of 64.8years (range 20–93). The CT scans were segmented and converted to virtual bones using custom CT analytical software. (SOMA™ V.4.0) Femoral Head Offset (FHO) and Femoral Head Position (FHP) were measured from head center to proximal canal central axis and to calcar or 20mm above Lesser Trochanter (LT) respectively. The Femoral neck Anteversion (FA) and Caput-Collum-Diaphyseal (CCD) angles were also measured. The Medial Lateral Widths(MLW_n) of femoral canal were measured at 0, -10, LT, -30, -40, -60, -70 and -100mm levels from calcar. Anterior Posterior Widths (APW_n) were measured at 0, -60 and -100mm levels. The Flare Index (FI) was derived from the ratio of widths at 0 and -60mmor FI=W₀/W₋₆₀. All measurements were performed in the same settings for both populations. The comparison was analyzed by Student T test. P<0.05 was considered significant.