Is guided growth a viable treatment option for angular deformity correction in distal renal tubular acidosis patients?

Background: Distal renal tubular acidosis (dRTA) is a rare disorder marked by impaired hydrogen ion secretion in the distal nephron, leading to metabolic acidosis and skeletal manifestations resembling rickets. While medical treatment with alkali, calcium, and vitamin D supplementation is essential, severe coronal plane knee deformities may necessitate surgical correction. Traditional osteotomy is an invasive modality, and data on less invasive options such as guided growth with eight-plate hemiepiphysiodesis in dRTA is limited. Methods: This retrospective study included seven children (6 males, 1 female; mean age: 11 years) of dRTA who underwent growth modulation with eight-platesfor genu valgum between 2019-2024 concurrently with medical management. Rate of angular deformity correction based on time interval between 8 plate placement and removal, and postoperative complications were recorded. Results: Six patients had distal femoral involvement and one had proximal tibial deformity. Correction was achieved in all cases, with no implant-related complications. The average rate of angular correction was 1.18°/month (range: 0.71-1.84°) in distal femoral cases and 0.54°/month (range: 0.52-0.56°) in the tibial case. One patient required staged implant removal due to initial difference in severity of deformity. No rebound deformity or recurrence was noted till last follow-up. Conclusion: Concurrent medical management and growth modulation using 8 plate is a feasible option for management of angular deformities in children with active distal renal tubular acidosis. This approach may reduce or eliminate the need for osteotomy, offering a less invasive alternative with promising outcomes.