Correction of Fixed Knee Flexion Deformity in Patients With Cerebral Palsy Using Suture Anchors for Anterior Distal Femur Hemi-epiphysiodesis.

Background: Fixed knee flexion deformity in skeletally immature patients with cerebral palsy (CP) is a common contributor to mobility impairment. Established techniques for guided growth using metal implants are associated with symptomatic hardware. This study provides early results following anterior distal femur hemi-epiphysiodesis (ADFHE) with a novel technique utilizing suture anchor-based nonmetallic implants.

Methods: We reviewed a consecutive series of skeletally immature patients with CP treated for fixed knee flexion contracture with ADFHE using this novel technique between April 2021 and March 2023 at a single tertiary care hospital. All surgeries were performed by a single board-certified pediatric orthopaedic surgeon. Age at surgery, ambulatory status, Gross Motor Function Classification System (GMFCS) level, concurrent lower extremity surgery, and preoperative and postoperative knee flexion contracture (degrees) were collected. Time to resolution of contracture (months) and correction rate (degrees/month) were calculated for each knee. All patients were followed for a minimum of 6 months postoperatively (or until full correction). Descriptive statistics and time-to-event analysis were performed.

Results: Twenty-one patients were included, of whom 19 underwent bilateral correction (N=40 knees); 14 patients (26 knees) were ambulatory, and 7 patients (14 knees) were non-ambulatory. Six patients were classified as GMFCS level II (29%), 8 level III (38%), 6 level IV (29%), and 1 as level V (5%). In the ambulatory patients, preoperative knee flexion contracture measured 12.9±6.6°. Final postoperative contracture measured 1.69±4.16°. Correction occurred at a rate of 2.0°/month over 11.9±10.2 months. In the non-ambulatory patients, preoperative knee flexion contracture measured 24.6±17.4°. Final postoperative knee flexion contracture measured 13.2±12.3°. Correction occurred at a rate of 1.6°/month over 13.5±0.3 months. Correction rate (P=0.71) and time-to-resolution of contracture (P=0.91) did not differ significantly based on ambulatory status. There were no complications or symptomatic hardware necessitating removal.

Conclusions: The use of suture anchor-based ADFHE technique for fixed knee flexion contracture is an effective technique in patients with CP, yielding results similar to those of historical techniques with a favorable complication profile.

Level of evidence: Level III.