OBJECTIVE: Extension stiffness of knee joint is always treated by the quadricepsplasty, but the main deficiency of this method is that patient feels weakness of lower limb and easily kneels down. The aim of this article is to explore the method to resolve the complications after quadricepsplasty. METHODS: Since 1978 to 1997, on the basis of traditional procedures of quadricepsplasty, sartorius muscle was used to reinforce the extension of knee joint. The lower 2/3 of sartorius muscle was fully dissociated only with its insertion intact. A tendon-periosteal-bone flap, about 2 cm in width, was managed on the anterior surface of patella, with its pedicle on the medial edge of patella. The tendon-periosteal-bone flap was used to fix the dissociated sartorious into patella to reinforce the extension of knee joint. The very lower part of sartorius was mainly aponeurosis, with the help of an aponeurosis bundle of iliotibial tract, it was fixed into the insertion of patellar ligament, through a bony tunnel chiseled adjacent to the insertion of patellar ligament. By now the movement of knee joint extension was strengthened by the transferred sartorius muscle. Postoperatively, every patient was required to extend and flex knee joint actively and/or passively. Altogether 12 patients were treated, 9 of them were followed up with an average of 14 months. RESULTS: The average movement was increased from 15 degrees to 102 degrees, and the average myodynamia was improved from grade II to grade IV. CONCLUSION: Traditional quadricepsplasty co-operated with transfer of sartorius muscle can strengthen the myodynamia of knee joint extension. It is simple method and can really achieve good function.