Infantile Blount's disease treated by hemiplateau elevation and epiphyseal distraction using a specific external fixator: preliminary report.

The treatment of infantile Blount's disease remains controversial. The progressive development of epiphysiodesis of the medial tibial physis induced a complex deformity of the lower limb such as severe genu varum, joint incongruity, torsion instability and leg length discrepancy with major functional consequences. Nine knees on eight children (average age was 7 years and 2 months) were treated by a one-time procedure using a specific external fixator that combined elevation of the medial tibial plateau, axial correction in the valgus, complete sterilization of the upper tibial growth cartilage, leg lengthening anticipation and de-rotation if necessary. Magnetic resonance imaging was useful to describe the deformity and to prepare for surgery. Corrections were progressively obtained through the physis plan by means of short incisions and the use of a specific external fixator. The primary results at an average of 24 months were good with a low rate of complications but final evaluation will be conducted at the end of the children's growth period.