Opening Wedge Osteotomy for the Correction of Adolescent Tibia Vara

Tibia vara, or Blount's disease, is a pathologic angular deformity of upper tibial physis causing a bow leg deformity. Adolescent Blount's disease may be unilateral or bilateral and is diagnosed during or just before the adolescent growth spurt. In addition to predisposing genetic factors, biomechanical overload of the proximal tibial physis causes asymmetric growth leading to a varus deformity.Surgical intervention is usually required for adolescent Blount's disease. Hemiepiphysiodesis has had some success in arresting or correcting the deformity. Tibial osteotomy can achieve correction acutely with internal or external fixation or gradually with external fixation.This article reports the outcomes of correcting adolescent tibia vara with a proximal opening wedge osteotomy (POWO) and internal fixation in nine patients with a primary diagnosis of Adolescent Blount's Disease.

We conducted a retrospective review of patients treated with POWO between April 2007 and July 2015. Fifty charts were selected using ICD9 codes for tibia vara and CPT codes for osteotomy. Nine patients (11 tibia) meeting eligibility criteria were identified. In addition to pre-operative data; operative factors, such as blood loss; and post-operative outcomes such as radiographic accuracy of correction, time to healing, time to full weight-bearing, number of office visits and complication rates were collected.

Pre-operative radiographic measurements showed the varus deformity was primarily tibial. Post-operative correction demonstrated a mean correction of 17.64° (range, 7°-26°). Patients returned to full weight bearing status around 67 days after surgery and required very few follow-up visits during the course of treatment. Three of nine patients experienced complications including seroma requiring drainage, metallosis mistaken for infection leading to hardware removal, and a wound abscess treated with antibiotics (one patient each). No patients lost correction, experienced nerve palsy, compartment syndrome nor complained of leg length discrepancy.

Proximal opening wedge osteotomy (POWO) is a reproducible, safe and effective technique for correction of adolescent tibia vara, with potential advantages of fewer return visits and sooner return to weight bearing than external fixation. In select patients, it is a useful alternative to external fixation or closing wedge osteotomy.Level of Evidence: IV.