Predicting patients' remaining angular growth and timing for hemiepiphysiodesis are crucial for correcting coronal plane knee deformities in children. We asked whether the Angular Deformity Versus Growth Remaining Chart predicted correction of coronal angular deformities of the knee in children. Serial orthoroentgenograms and the predictive chart were used to time percutaneous hemiepiphysiodesis, and the children were followed until skeletal maturity. Twenty-rive consecutive children (35 extremities) with a mean skeletal age of 13 years (range, 9.6-16 years) had percutaneous hemiepiphysiodeses as described by Bowen and Johnson, and were followed up until skeletal maturity. At skeletal maturity, correction of varus and valgus coronal plane deformities were within 2 degrees (range, 0 degrees-6 degrees) of the predicted value. The maximum limb-length discrepancy resulting from the procedure was 1.5 cm. The only complication was failure of a physeal bar formation hemiepiphysiodesis; this was treated successfully with a repeat percutaneous hemiepiphysiodesis. The percutaneous hemiepiphysiodesis is effective and has a low complication rate. Angular correction and timing for hemiepiphysiodesis can be predicted by using the Angular Deformity Versus Growth Remaining Chart in children with coronal plain knee deformities.