Rotational malalignment in osteoarthritic knees

ABSTRACT

To study the rotational alignment of lower limbs in patients with osteoarthritis of the knees, measuring two of its components, knee rotation and tibial torsion, by computer tomography. Material and Method: 46 subjects [36 patients with osteoarthritis of the knees and 10 age- and sex-matched asymptomatic volunteers] were included in the study. Cases were required to be "knee pain positive", ascertained using a previously standardized questionnaire and to have at least grade 3 radiographic changes using Kellgren and Lawrence criteria. All 92 limbs were scanned at the level of distal femoral condyle, proximal tibial condyles and ankle joint. Rotation of the knee joint was measured as an angle between the tangent to the dorsal aspect of femoral condyles [pro x i m a l reference line] and the dorsal tangent to the tibial condyles. Tibial torsion was measured as an inclination between the dorsal tangent to the tibial condyles and the tangent to the distal tibia at the level of the medial malleolus. The mean values of the two variables were reduced in patients with osteoarthritis of the knee. The decrease of tibial torsion [28.3° +/- 5.1°] in the osteoarthritic patients compared to the control group [35.4° +/- 6.2°] showed significance. Rotational malalignment may have some implications in the genesis of osteoarthritis of the rotationally intolerant knee joint