Many people who sustain injuries to the femur or muscles of thigh are handicapped for life by varing degree of limitation of motion of the knee joint flexion such as squatting or kneeling. Many surgical procedures were reported by Thompson (1944), Judet (1959), van Nes (1962), Nicoll (1963), Hesketh (1963), Jahng (1965), Han (1979, 1986), and Daoud (1982). During the period from March 1987 to August 1989, 12 cases of stiff knee joint were treated surgically in our clinics. l. 12 cases of stiff knee treated by modified Judet technique of quadricepsplasty and arthrolysis. 2. The stiff knee was corrected successfully without release of rectus femoris muscle in our cases. 3. The string tie was very useful in postoperative care. String tie was applied with the knee in a full flexed position and when it was discarded, knee was extended and quadriceps setting exercise was begun. 4. In 10 cases, plate removal was added, in two eases, combined bone surgery and quadricepsplasty for malunion or nonunion of the femur, which showed good results. 5. The average flexion achieved by operation was 119.6, the average flexion gain 70.8, while the average extension gain 8.8. 6. By Judet criteria, the result of 11 cases were excellent and one case showed fair result.