Résumé : Knee extension stiffness due to fibrous retraction of the quadriceps is a relatively uncommon condition in children but not so rare in developing countries. It is the result of iatrogenic intra-muscular injection. It is responsible for major functional prejudices in the child. A retrospective study was carried out over a period of 4 years. Twenty children were treated surgically for knee extension stiffness. In 100% of cases it was a severe retraction of the knee. The quadriceps-plasty described by Judet was used in 16 cases and a V-Y quadriceps-plasty in 4 cases. Immediate post-operative physiotherapy was performed every 6 hours with positioning in splint (with every 6-hour alternation between extension and 100°-flexion splint). The average knee flexion degree was 5° in preoperative period and improved to 103° after the surgery. The final result was considered excellent in 30% and good in 70% of the cases.