BackgroundIn childhood, for flexible clubfoot deformity, the transfer of the tendon of the tibialis anterior muscle is widely used. In contrast, extensive surgical procedures are required for fixed clubfoot deformities. MethodsWe describe the peroneus longus tendon transfer to the peroneus brevis tendon, additionally to full surgical release, in cases of recurrent fixed clubfoot deformities. The purpose of this surgical technique was to restore and maintain the dynamic balance of foot inversion-eversion during the gait cycle by augmenting the muscular strength of the weak peroneus brevis tendon. We report the prospective study of treatment outcome of twenty recurrent fixed clubfoot deformities in twelve children (20 feet) after failed surgical treatment they had. Anteroposterior and lateral radiographs under full-body weight-bearing and the AOFAS score pre-and postoperatively were used in all patients. For the estimation of the severity of the recurrent clubfoot deformity in each child and to increase the credibility of the AOFAS rating scale, we additionally used a clubfoot sheet score preoperatively and postoperatively (maximum score 100 points for normal foot appearance clinically and radiologically). ResultsThe mean age at surgery was 6,85 (±1,81; 5–11) years. The mean follow-up time was 5,4 (±1,7; 2–8) years. The mean AOFAS ankle-hindfoot rating score increased from 69,85 (±9,51; 53–82) points preoperatively to 94,4 (±2,43; 91–97) points postoperatively. The mean clubfoot sheet rating score increased from 43,00 (±12,18; 15–55) points, preoperatively to 90,0 (±4,58; 80–95) points postoperatively. The two-tailed p-value was < 0,0001. ConclusionsThe transfer of the peroneus longus tendon to the peroneus brevis tendon is a minimal surgical procedure that acts collaboratively in maintaining the correction of foot deformity, achieved by the complete surgical release. Level of Evidence: IV.