A Child with Severe Bilateral Tibia Vara: Treatment with Computer-Assisted Gradual Correction Utilizing Hexapod External Fixator

Abstract

A 7-year-old obese boy presented to the Paediatric Orthopaedic clinic with a complaint of worsening bilateral knee bowing. He was initially seen for the same problem in another hospital at the age of 3. The bowing of the leg was associated with pain over the lateral aspect of both knees. He was able to walk but unable to run or participate in sports due to the deformity and knee pain. On examination, the child had a waddling gait and lateral thrust due to severe bilateral genu varus. The range of motion of bilateral knee joints was 0 to 110 degrees. The knee intercondylar distance was markedly increased and there was bilateral tibial torsion. No limb length discrepancy and neurovascular examination was normal. The radiograph revealed features of infantile tibia vara (Blount disease). Bilateral proximal tibia temporary hemiepiphysiodesis was attempted but no correction of the deformity was achieved due to implant failure. His parents were then counseled to let him undergo gradual deformity correction surgery using a ring external fixator (hexapod system). The bilateral varus deformity was corrected after 4 months, and the patient was able to walk normally.