The Bone Mineral Density of the Proximal Tibia, Lumbar Spine and Proximal Femur and Its Correlation with the Alignment of the Lower Extremity in Knee Osteoarthritic Patients

ABSTRACT

PURPOSE: The purpose of this study was to measure the bone mineral density (BMD) of the proximal tibia, lumbar spine and proximal femur and to determine out their correlations with the knee alignment in knee osteoarthritic (OA) patients. MATERIALS AND METHODS: The study involved 203 patients (322 knees) with knee osteoarthritis and who had underwent total knee arthroplasty from July 2005 to September 2006. The BMDs of the proximal tibia, lumbar spine and proximal femur were measured and compared. The knee alignment was checked and its correlation with each BMD was analyzed. RESULTS: The mean BMD of the medial proximal tibia, lateral proximal tibia, lumbar spine and proximal femur were 0.857+/-0.180 g/cm(2), 0.772+/-0.177 g/cm(2), 0.940+/-0.174 g/cm(2), and 0.721+/-0.126 g/cm(2), respectively. The mean knee alignment was 10.2+/-4.7degrees varus and the deformity got severe as the BMD of the lateral proximal tibia, lumbar spine and proximal femur were lower and that of the medial proximal tibia was higher. CONCLUSION: The BMD of the proximal tibia was lower than that of the lumbar spine and higher than that of the proximal femur in patients with knee osteoarthritis. The BMDs of the lateral proximal tibia, lumbar spine and proximal femur were negatively correlated with the degree of varus deformity, but that of the medial proximal tibia was positively correlated.