Anterior Distal Femoral Hemiepiphysiodesis Using Coronally Oriented 8-plates for the Correction of Fixed Knee Flexion Deformities in Children-Preliminary Results.

Introduction: The original technique for guided growth of the distal femur for correction of pediatric fixed knee flexion deformities (FKFDs) involves the utilization of two 8-plates inserted on either side of the trochlear groove, a technique that has been frequently linked to the development of persistent postoperative knee pain and crepitus. The present study aimed to assess the preliminary results of a novel technique where the two 8-plates are fixed in the coronal plane, one on each of the medial and lateral surfaces, so that they occupy the anterior part of the distal femur.

Methods: Our study was a prospective case series that included cases with FKFD of >10 degrees in children with at least 12 months of predicted growth remaining. The preoperative knee flexion contracture angle was documented. The surgical procedure entailed the insertion of 2 coronally oriented 8-plates on the medial and lateral surfaces of the distal femur as anterior as possible to the axis of the femur without encroachment on the trochlear groove. The duration of time required to attain full knee extension and any complications encountered were recorded. Wilcoxon signed-rank was used to compare the preoperative and final contracture angles. The level of statistical significance was set at P <0.05.

Results: Thirteen knees in 8 patients (6 boys and 2 girls) were included. The median age was 11 years (6 to 14). There was a significant improvement in the FKFD for the whole cohort from 25 degrees (14 to 42) to 0 degrees (-9 to 8), P <0.05. The median rate of correction was 2.0 degrees/month (0.9 to 5.8). The time till full correction was 14 months (4 to 25). Postoperative knee pain and metalware-related complications were not reported by any patient during follow-up.

Conclusions: Guided growth of the distal femur using coronally oriented 8-plates is an effective procedure for the treatment of FKFDs in children. This modified technique may achieve faster correction while minimizing the risk of postoperative knee pain compared with the conventional technique.

Level of evidence: Level IV-case series.