The purposes of this study were to evaluate the efficacy of deformity correction of the knee and leg lengthening by the Ilizarov method in patients with vitamin D resistant rickets (VDRR) .

There were 7 patients with average age of 13 years and 6 months. 5 patients had genu varum and 2, genu valgum. 3 patients underwent deformity correction alone in 4 femora, and the remaining 4 patients underwent concomitant deformity correction and lengthening in 5 femora, and 12 tibiae and fibulae.

Angular correction averaged 22.6. and the amount of lengthening averaged 3.5 cm. The healing index (H.I) averaged 2.1 month/cm. But those who had serum phosphate level more than 2.5 mg/dL showed rapid regenerate bone healing (H.I: 1.6 month/cm) . There was a statistically negative correlation between H.I and the level of serum phosphate.

Maintenance of appropriate serum phosphate level (> or = 2.5 mg/dL) is important for satisfactory regenerate bone healing in due time in patients with VDRR. The recurrence rate of deformity appears to be relatively higher in immature patients.