A New Classification for Idiopathic Genu Vara

PURPOSE Past classification for the treatment of idiopathic genu vara depended simply on the measurement of distance between the knees, without attention to the rotational profile of the lower extremity. We retrospectively analyzed anatomical causes of idiopathic genu vara. PATIENTS AND METHODS Twenty eight patients with idiopathic genu vara were included in this study. All patients were surgically treated. To evaluate the angular deformity, a standing orthoroentgenogram was taken and the lateral distal femoral angle and the medial proximal tibial angle were measured. In order to assess any accompanying torsional deformity, both femoral anteversion and tibial external rotation were measured using computerized tomographic scans. A derotational osteotomy was performed at the femur or tibia to correct rotational deformity, and a correctional osteotomy was performed at the tibia to correct angular deformity. RESULTS Satisfactory functional results were obtained in all cases. Genu vara was divided into 3 groups according to the nature of the deformity; group 1 (6 patients) with increased femoral anteversion, group 2 (10 patients) with proximal tibial varus deformity alone, and group 3 (12 patients) with proximal tibial varus deformity accompanied by increased external tibial rotation. CONCLUSION The success seen in our cases highlights the importance of an accurate preoperative analysis that accounts for both rotational and angular deformities that may underlie idiopathic genu vara.