Bone Abstracts

Purpose: The purpose of this study is to analyse regional differences in the microstructural and mechanical properties of the distal femur depending on osteoarthritic changes using micro-images based on finite element analysis.

Materials and methods: Distal femur specimens were obtained from ten donors composed of ten women with OA (mean age of 65 years, ranging from 53 to 79). As controls, the normal distal femur was sampled from age and gender matched donors consisting of ten women (mean age of 67 years, ranging from 58 to 81). The areas of interest were six regions of the condyles of the femur (lateral-anterior, middle, posterior; medial-anterior, middle, posterior). A total of 20 specimens were scanned using the micro-CT system. Micro-CT images were converted to micro-finite element model using the mesh technique, and micro-finite element analysis was then performed for assessment of the mechanical properties.

Results: Trabecular bones from the distal femur in control and OA groups exhibited different microstructural and mechanical properties in the same region. BV/TV, Tb.N, Tb.S and Yield strength were different between LA and MM significantly (P=0.005). In control group, the lateral anterior region of the distal femur reflected subchondral trabecular remodeling, while in advanced OA group, the medial middle region showed prominent changes in the microstructural and mechanical properties.

Conclusion: The authors concluded that with aging and the progress of primary OA, changes of patello-femoral reaction force induced subchondral trabecular changes of the anterolateral region initially, and then progressed to the medial middle and posterior region in advanced OA.