Bone mineral density of the proximal tibia relates to axial torsion in the lower limb

This study sought to determine the relationship between bone mineral density distribution in the proximal tibia and tibial and femoral torsions, hip-knee-ankle angle, hip rotation index (internal − external rotation), knee abduction moments, and the foot progression angle. Simple linear regression found that the hip rotation index (r = −0.59, p < 0.001), tibial torsion (r = −0.41, p = 0.004), and knee abduction moments (r = 0.39, p = 0.005) were significantly related to medial–lateral BMD ratio for all subjects. The three variables were then studied together to determine their relationship to the bone mineral distribution in the proximal tibia using multiple linear regression (r = 0.80, p < 0.001). These findings suggest that higher medial knee joint loads, loss of internal rotation of the hip, and internal tibial torsion may lead to increased medial versus lateral BMD of the proximal tibia of healthy knees. Similar bone distribution patterns are found in knees with osteoarthritis; therefore, we suggest these may be risk factors.