Two-bundle posterior cruciate ligament reconstruction better replicates anatomy

Consider PCL’s distinct anatomy and if the injury is chronic or acute when planning a reconstruction.

Issue: January 2008

SAN FRANCISCO — Arthroscopic double-bundle posterior cruciate ligament reconstruction may offer long-term benefits to patients, particularly in cases of chronic insufficiency, and clinical results are frequently comparable to those attained with single-bundle techniques, according to an orthopedic investigator.

“Anatomic dissection, I think, supports, two bundles. Biomechanically, studies favor two bundles but at the present time there really is no published clinical data that two bundles are better than one,” Donald H. Johnson, MD, FRCS, a member of the Orthopedics Today Editorial Board, said. “But most surgeons … tend to do double bundles in chronic situations empirically without any strong evidence.”

Johnson favors an arthroscopic double-bundle approach to posterior cruciate ligament (PCL) reconstructions for a variety of reasons which he offered, along with other issues related to the procedure, during a master lecture at the Arthroscopy Association of North American annual meeting here.

Insertion sites on a femur for double-bundle PCL reconstruction
Outlined in black are the native insertion sites on the femur for double-bundle posterior cruciate ligament (PCL) reconstruction. The bottom circle indicates the posteromedial (PM) bundle and the top one the anterolateral (AL) bundle sites. To the right of where the circles intersect is the anterior medial femoral ligament attachment site.

Johnson prefers using double-bundle allografts for PCL reconstruction, such as this Achilles tendon allograft. Graft choice is not as critical a factor with PCL surgery as it is with ACL reconstruction surgery. In fact, he found autogenous quads tendons to be similar in appearance and function.

Images: Johnson DH

Use two bundles

Double-bundle reconstruction has been shown to be more anatomic depending on where the bone tunnels are placed. Laboratory studies demonstrate this type of arthroscopic PCL reconstruction is more biomechanically sound than its single-bundle counterpart.

Single-bundle reconstruction of the PCL is probably adequate for acute reconstructions, although in both situations two tibial tunnels are typically not favored, according to Johnson.

David R. McAllister, MD, noted in a lecture on the advantages of single-bundle arthroscopic PCL surgery given at the same meeting that several downsides to two-bundle PCL reconstruction currently exist. Among them, the technique requires extra surgical time, allograft tissue and more fixation hardware.

“I agree with David’s comments. It is more difficult with a longer operating time, so you have to make a decision in a chronic situation whether or not you are going to use this,” Johnson said.

This alternative view of the femur shows the anatomic sites of the AL and the PM bundles based on measurements Craig D. Morgan, MD, made arthroscopically. These measurements placed the PM bundle slightly more distal than did other researchers.

Anatomical reproduction

During his presentation, Johnson stressed how important it is to the procedure’s outcome that surgeons be familiar with the anatomy of the PCL and surrounding knee structures.

The major problem in trying to reproduce the anatomy is there is a broad ligament repair insertion site and a large meniscal femoral ligament in front and a small compact insertion at the back of the tibia that is difficult to access, he explained.

Two-bundle results

Although he prefers a two-bundle approach, Johnson admitted support for it is not universal. He noted a recent study by John A. Bergfeld, MD, that showed that there was no significant difference in using one bundle vs. two bundles.

Further fueling the debate over which procedure is best, there are no clear-cut indications for a double-bundle PCL reconstruction, except perhaps for cases of chronic PCL tears, Johnson noted. Some kind of reconstruction is indicated for acute complete tears, but in the long run a double-bundle reconstruction is probably the solution that best benefits anyone with chronic ligamentous laxity, he said.

Also, many technique-related issues remain unresolved. PCL reconstruction outcomes will benefit from further investigation into optimal location of the two tunnels and of the grafts relative to the meniscal femoral ligament, Johnson said. Some recent studies by investigators like Bergfeld and Frank R. Noyes, MD, looked closely at these areas and brought critical new information to light. But they also increased surgeon uncertainty about where to place the tunnels for optimal results.

Graft choice is not as critical a factor with PCL reconstruction as it is reportedly with ACL reconstruction, he added.

For more information:

Donald H. Johnson, MD, FRCS, can be reached at Sports Medicine Clinic, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6; 613-520-3510; e-mail: Johnson_don@rogers.com. He has indicated he is a consultant to ConMed Linvatec Corporation.

References:

Fanelli, GC, Edson, CJ. Arthroscopically assisted combined ACL/PCL reconstruction: 2-10 year follow-up. Arthroscopy. 2002;18(7):703-714.
Johnson DH. Master Lecture: PCL reconstruction: Two is better than one. Presented at the Arthroscopy Association of North American 26th Annual Meeting. April 26-29, 2007. San Francisco.