Growth Modulation for Fixed Flexion Contracture of the Knee: A Comparison of Two Techniques

Introduction: Growth modulation has become a mainstream treatment for frontal plane angular lower extremity deformities in children. Few studies report the effect of growth modulation on sagittal deformity, particularly fixed flexion contractures. Our aim is to compare two anterior distal femoral growth modulation techniques for fixed flexion contracture.

Methods: Retrospective medical record review was conducted for patients who underwent insertion of either transphyseal screws-only or tension-band plate constructs into the anterior distal femoral hemiphysis to treat fixed flexion contracture. Patients were excluded if adequate preoperative/postoperative radiographs were not available. Frontal and sagittal plane joint orientation angles as well as hardware failures/migration were evaluated preoperatively and at least 10 months after implantation.

Results: Of 26 patients (39 knees) identified, 18 patients (29 knees) were included in the study. Thirteen knees (9 patients) were treated with an anterior tension-band plate construct, and 16 knees (9 patients) were treated with a screws-only construct. Duration of follow-up was 45 months (range, 10–96 months). Average age was 10.7 years (range, 3–14 years). Hardware migration was noted in one of 13 cases for the tension-band plate, and in 9 of 16 cases with the screws-only construct (p=0.008). Improvement in sagittal alignment was noted in both groups. Statistically significant changes were noted in the posterior distal femoral angle in the tension-band plate group (p=0.009), but not in the screws-only group (p=0.181). Posterior proximal tibial angle did not significantly change in tension-band plate group (p=0.524) or the screws-only group (p=0.667).

Discussion: Anterior distal femoral growth modulation improves sagittal alignment of the femur without affecting the sagittal alignment of the proximal tibia. Hardware migration occurred more often in the screws-only construct (p=0.008). We recommend anterior tension-band plating instead of placement of screws for sagittal plane growth modulation to treat knee fixed flexion contracture.