[Chronic instability after posterior cruciate ligament injury. Tactics, techniques, and results].

This article reviews the surgical treatment of chronic posterior knee instability. The treatment rationale includes exact definition of the instability pattern ("envelope-of-motion" of the tibia) by clinical examination, arthrometry and stress radiography. Exact evaluation of the osseous anatomy is mandatory to identify an eventual varus morphotype. This osseous variant in combination with posterior/posterolateral instability should be treated by an osteotomy in every case. The technique of additive osteotomy to correct varus and increase the sagittal tilt of the proximal tibia is described. Ligament reconstruction in chronic posterior knee instability must address the posterior cruciate ligament and the lateral/posterolateral structures in many cases. Patellar tendon grafts, quadriceps tendon grafts or hamstrings can be used for posterior cruciate ligament replacement. Arthroscopic or mini-open techniques may be used for graft placement, direct posterior fixation of the graft via a posterior incision is an option for patellar tendon grafts. Bousquet's biceps plasty or Clancy's biceps tenodesis may be used for posterolateral stabilization; a biceps tendon strip can also be used for lateral collateral ligament reconstruction. Results of surgery are still moderate. In the author's series of chronic posterior/posterolateral instability, 26 cases were treated with posterior cruciate ligament reconstruction and biceps tenodesis. Follow-up at 18 months demonstrated increased stability (mean residual posterior drawer 8 mm at 70 degrees and 20 lb force) and improved knee function (33 % IKDC B, 67 % IKDC C). Presently, surgical treatment of chronic posterior knee instability should be restricted to centers devoted to this problem.