Determining the degree of cortical bone asymmetry in bilateral, nonpathological, human femur pairs.
When testing the effects of a femoral component on cortical bone following total hip arthroplasty, the patient's implanted femur is often compared with his/her contralateral nonimplanted femur, with differences attributed to the femoral component. However, if normal anatomical differences exist between bilateral femurs, they need to be quantified in order to validate whether the differences between implanted and nonimplanted bilateral femurs are due to the implant or possibility due to intrinsic differences before implantation. This study quantified the geometric properties of cortical bone shape between seven pairs of bilateral, cadaveric, human femurs. The null hypothesis tested stated that the bilateral femurs would not be significantly different in cortical bone geometry. Digitized images of cortical bone cross-sections taken at percent biomechanical lengths (levels 1-8) were used to calculate bone geometry measurements. The paired t-test showed that the only significant difference was in the location of principal axes at the most proximal location, level 1 (p = 0.015). All other measurements and levels were not significant with percent differences less than 6.6%. In conclusion, the data supports attributing cortical bone shape differences between implanted and contralateral nonimplanted femurs in levels 2-8 to the presence of the implant when the significant differences are greater than 6.6%.
Rosenbaum
Teri G
TG
Bone & Joint Research Lab (151F), SLC VA Health Care System, 500 Foothill Blvd., Salt Lake City, UT 84148, USA.
Hamblin
Tracy
T
Bloebaum
Roy D
RD
D000328:Adult; D019644:Arthroplasty, Replacement, Hip / Q000379:methods; D005260:Female; D005269:Femur / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012107:Research Design