The challenges of a comprehensive surgical approach to Blount’s disease

Purpose The purpose of this study is to evaluate a surgical technique that aims to address the multi-planar deformities occurring in early onset Blount's disease. Methods Seven patients (eight lower limbs) with early onset Blount's disease were treated with a surgical technique that used an external fixator to simultaneously address all aspects of deformity. Presenting radiographic parameters including mechanical axis deviation (MAD), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA) and medial plateau angle (MPA) were compared with final follow-up and the unaffected limb. Data was also collected on surgical complications and functional outcomes. Results After a mean interval of 4.6 years (2.2 to 9), the MAD of the affected limb improved from 4.85 cm to 1.88 cm, MPTA from 43.58° to 75.46° and MPA from 43.41° to 20.71°. The mean time in the external fixator was 5.6 months (3.5 to 10.4). Recurrence was noted in three patients; two had evidence of nerve injury and one patient had premature fibular consolidation. Conclusion The surgical technique described in this study has attempted to address the complex multiaxial deformity that is encountered in Blount's disease. It identifies difficulties and limitations in developing a comprehensive surgical protocol and highlights complications associated with this approach.