Treatment of fixed knee flexion deformity by anterior distal femoral stapling.

Purpose: The treatment of fixed knee flexion deformity through anterior distal femoral stapling has been investigated in only two studies so far, with promising results. The aim of the present study was to determine whether this technique might improve fixed knee flexion deformity in a series of growing children and adolescents with different conditions. Follow-up examinations were continued after staple removal in terms of a possible impairment of this deformity.

Methods: We reviewed the medical records of all patients with fixed knee flexion deformity who had been treated by anterior distal femoral stapling at our institution. Twenty patients (37 knees) with a mean age of 12.7 years met the inclusion criteria (>12 months of follow-up; no additional procedures to correct fixed knee flexion deformity such as hamstring lengthening or posterior capsulotomy) and were evaluated in this study.

Results: The mean fixed knee flexion deformity significantly improved from 21.4° (SD = 11.6) preoperatively to 7.0° (SD = 9.8) after a mean follow-up of 35.3 months. Young patients (<12 years) revealed superior improvement of this deformity, and especially children with distinct fixed knee flexion deformity of 30° or greater had benefit from early treatment. Impairment of flexion deformity was only seen in one patient (2 knees) after staple removal.

Conclusions: Our results demonstrate that anterior distal femoral stapling is an effective method for the treatment of fixed knee flexion deformity in growing children and adolescents. Rare complications, immediate mobilization, and a low recurrence rate after staple removal provide obvious advantages of this minimally invasive procedure.

Level Of Evidence: Retrospective therapeutic study, Level IV.