Background: It has been suggested that double-level osteotomy can prevent the occurrence of joint line obliquity, as one of the complications following high tibial osteotomy. In this study, we compared the preoperative distal femoral and proximal tibial obliquity in patients with primary genu varum with a group of normal subjects.

Methods: 75 patients with primary genu varum and 75 normal persons, contributed to a case-control study. The medial distal femoral mechanical angle (MDFMA), medial proximal tibial mechanical angle (MPTMA) and joint diversion angle (JDA) were measured and compared between the two groups. The percentage of patients with >3 degrees in both distal of femur and proximal of tibia were determined.

Results: The mean of MDFMA and MPTMA was significantly lower and the mean of JDA was significantly higher in genu varum group compared to normal group (p < /em>3 degrees.

Conclusions: The alignment of distal femur and proximal tibia is significantly different in patients with primary genu varum and normal controls. Abnormal alignment of joint line is a common finding in both primary genu varum and normal people but more commonly in the cases of genu varum. As double level osteotomy may be required in many patients with genu varum, it is important to investigate distal of femur alignment before high tibial osteotomy