In 21 patients the treatment described in an original communication by Bousquet for chronic anteromedial anterolateral instability of the knee was applied. The basic components of treatment were static-dynamic substitution of the anterior crucial ligaments by the proximally pedunculated gracilis tendon, tightening of the dorsomedial capsule, bypass of the popliteal tendon, revision of the joint, treatment of medial instabilities with conservation of the menisci if possible, postoperative treatment without plaster and mobilization without weight-bearing until active bending at 90 degrees was attained. Of the 21 patients treated between April 1983 and December 1984, 18 were examined again an average of 52.5 months after treatment. According to a postoperative examination checklist, results were found to be excellent in 8 cases, good in 9, moderate in 1 and poor in another case. In spite of the good results a definite opinion of the method cannot be given.