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.