Guided growth for the correction of angular lower limb deformity: Correction rates for idiopathic and non-idiopathic aetiologies.

INTRODUCTION

Coronal plane knee deformities are frequent in children and may arise from idiopathic or nonidiopathic causes, leading to cosmetic, functional, or early degenerative issues. Guided growth using tension band plates is an established corrective method, but its predictability - especially in nonidiopathic cases - needs further evaluation. This study analyzed correction rates (CR) and treatment outcomes in different etiologies.

METHODS

A retrospective review included patients treated for coronal plane deformities with tension band plates from 2009 to 2021. Patients were classified according to etiology. Radiographic measurements (mechanical axis deviation, mLDFA, and mMPTA) were compared between baseline and end of correction. Analyses regarding treatment success, CR and predictors for CR and success were performed.

RESULTS

The analysis included 654 growth modulations in 313 children; distal femur (55.4%), proximal tibia (44.6%), both (42.2%. The average CR for mLDFA was 0.67 (+/-0.55)°/month and for mMPTA 0.43 (+/-0.38)°/month. CR significantly varied by etiology (p < 0.001), with older age at surgery and varus deformity predicting lower CRs. Neutral mechanical axis was achieved in 68.7% of patients. Significant differences between etiologies were seen, and complete correction was achieved significantly more often in patients with idiopathic etiology compared to nonidiopathic etiologies; 78.2% vs. 66.3% respectively, p = 0.02.

CONCLUSION

Hemi-epiphysiodesis is effective for correcting coronal plane deformities in children, but CR differs by etiology and incomplete correction is not uncommon. These factors should inform treatment planning and follow-up.

LEVEL OF EVIDENCE: Level IV, case-series.