Chronic anteromedial rotatory instability has not been demonstrated to have a satisfactory solution and we have experienced recurrence of the instability after operations. So the authors devised a new operative technique for the TCL (Tibial collateral ligament), that is, burying of the torn end of the ligament beneath the “ㄷ” shaped bony flap. It would better be called advancement and bony reinsertion operation. And we performed modifed MacIntosh tenodesis for the torn anterior cruciate ligament. The results were as follows: l. Of six knees, four (66.6%) rated “good”, two (33.3%) “fair”, and none (O%) “poor” (follow-up period; at least 6 months). 2. The technical problem of the advancement and bony reinsertion operation was discussed.