Regional Distribution of Stress on the Distal Femur in Advanced Osteoarthritis.

Background: The aim of this study was to analyze regional differences in the stress distribution within the distal femur in advanced osteoarthritis (OA).

Methods: Distal femoral specimens with primary OA were obtained from 10 female donor cadavers (mean age, 65 years; range, 53-79). As controls, distal femurs without OA were obtained from 10 age- and sex-matched female cadavers (mean age, 67 years; range, 58-81). The articular surface of the distal femur was divided into anterior, middle, and posterior regions on each condyle. Mechanical properties and microstructure were assessed for each region with micro-computed tomography and finite element model analysis.

Results: The control group showed differences in stress distribution among 6 regions on the distal femur ( P =0.037), but there was no regional difference in stress distribution among 6 regions on the distal femur in the advanced OA group ( P =0.179).

Conclusions: Regional stress distribution in the distal femur was different between advanced OA and normal groups. There were no regional differences in stress distribution in the advanced OA group. Altered loading patterns, bone remodeling, and chemical composition will affect stress distribution.