Posterior Cruciate Ligament Surgery: The Debate Continues
Abstract & Commentary
Synopsis: Long-term follow-up studies of arthroscopic reconstruction of the completely torn posterior cruciate ligament have found results to be fair, at best, with continued evidence of tibial drop-back often seen clinically.
Sources: Burks RT, Schaffer JJ. A simplified approach to the tibial attachment of the posterior cruciate ligament. Clin Orthop Rel Res 1990;254:216-219; Berg EE. Posterior cruciate ligament tibial inlay reconstruction. Arthroscopy 1995; 11(1):69-76.
Long-term follow-up studies of arthroscopic reconstruction of the completely torn posterior cruciate ligament (PCL) have found results to be fair, at best, with continued evidence of tibial drop-back often seen clinically.
Surgical technique, isometry of the tunnels, and graft selection have all been cited as causes of the poor results. Furthermore, the arthroscopic techniques that use an anterior to posterior tibial tunnel create a sharp turn posteriorly ("the killer turn"), which is believed to lead to graft failures. Passage of PCL grafts through this tunnel is also fraught with difficulty, and such a sharp turn on the tibial side frequently complicates even the most smoothly running procedure. In 1990, Burks published a simplified technique for the tibial attachment of the PCL. This approach stimulated Berg to describe his technique of "tibial inlay reconstruction" using a posterior approach to the knee joint with attachment of the medial head of the gastrocnemius and placement of the tibial bone plug (ideally a bone/tendon/bone autograft patellar tendon) directly into a tibial trough. Berg positions the patient in the lateral decubitus position with the injured knee side up. The knee is first examined by arthroscope with the knee flexed and the leg externally rotated. Graft harvest, arthroscopy, and femoral tunnel preparation are performed using the standard arthroscopic methods. The leg is then extended and abducted to expose the back of the knee and a posterior S-shaped incision is made across the knee flexion crease. Careful dissection allows access to the posterior aspect of the joint, after release of the medial head of the gastrocnemius. The neurovascular bundle is retracted gently. The tibial stump of the PCL is debrided and a cortical window is made in the posterior tibia, approximating the size of the graft bone plug. The femoral side of the reconstruction is fixed with an interference screw, and the tibial inlay portion is fixed with a standard cancellous screw and washer. The results of treatment in Berg’s four patients showed fairly good clinical function, but the patients had some measurable instability at the two-year follow-up point.
Comment by Robert C. Schenck, Jr., MD
The tibial inlay technique, while solving the problem of the "killer turn," creates new problems with access to the posterior knee and its complex anatomy. The term "onlay" has been used by some to describe this technique, but most surgeons feel the graft plug can be placed into the tibia to create a flush surface and thus "inlay" is probably a more accurate term. Some surgeons feel this technique requires positioning the patient prone for one portion of the procedure. Prone positioning complicates the operation and is less attractive in trauma patients, the population in which the PCL is frequently injured. While in his four patients, Berg noted no loss of postoperative extension, an incision in the flexion crease carries the risk of creating a postoperative flexion contracture and limitation of knee motion. This inlay technique will require evaluation in a larger number of patients prior to its universal acceptance; however, it is becoming a popular approach in many sports surgeons’ hands.