Sometimes surgery to reconstruct a ruptured anterior cruciate ligament (ACL) in the knee doesn't give the expected results. Either the patient continues to have a painful, unstable knee that gives out from underneath them or the knee is stiff and doesn't move well. Joint infection and arthritis are two other problems that can develop.
Why does this happen? In this article, surgeons from the University of Utah explore all sides of the dilemma of the failed ACL reconstruction from patient factors to surgeon error. They offer their own preferred techniques including graft type, bone preparation, graft fixation, and technical considerations for revision surgery.
But before we look at those more closely, it might be helpful to have a quick review of the anatomy of the anterior cruciate ligament (ACL). The ACL is located in the center of the knee joint where it runs from the backside of the femur (thighbone) to connect to the front of the tibia (shinbone). The ACL runs through a special notch in the femur called the intercondylar notch and attaches to a special area of the tibia called the tibial spine.
The ACL is the main controller of how far forward the tibia moves forward under the femur. This is called anterior translation of the tibia. If the tibia moves too far, the ACL can rupture. The ACL is also the first ligament that becomes tight when the knee is straightened. If the knee is forced past this point, or hyperextended, the ACL can be torn.
Once the ligament has been damaged enough to rupture completely, surgery is needed. The surgeon uses tendon material from either the patellar tendon below the knee or the hamstring tendon behind the knee to act as a graft and replace the ruptured ACL. But reconstruction surgery doesn't always hold up. Reconstruction failure can occur as a result of patient-related factors or surgeon error.
What happens on the patient side? Going back to demanding sports activities too soon is one potential error on the part of the patient. Overly aggressive rehabilitation can set the patient back. Too often the patient pushes past the guidance offered by the physical therapist. "More is better" is not the best motto during ACL reconstruction rehab. On the other side of the coin, too little rehab (poor patient compliance) can also contribute to a failed ACL reconstruction.
Surgeons play a role in the success or failure of ACL reconstruction. Poor graft placement, surgical contamination leading to infection, or other poor operative techniques can spell disaster. Putting the graft in the proper anatomical place but with too much or too little tension is another potential surgeon-related error.
What can be done when a torn ACL has been reconstructed and ruptures again? A second surgery called a revision procedure is often recommended. How this procedure is done depends on several factors. Length of time between re-rupture and revision surgery is one factor. Type and severity of damage done in the graft is another consideration. And technique used to perform the first reconstruction surgery is important (e.g., placement of tunnels in bone through which the graft is placed, angle of the graft as it is stitched in place).
Using diagrams (drawings) and photos taken during arthroscopic revision surgery, the authors show how to remove or work around sutures from the first (failed) ACL reconstruction. When a new tunnel must be drilled through the bone because of a malpositioned first tunnel, directions, placement, and photos are provided to guide the surgeon.
A review of hardware used to hold the new graft in place is offered. One method for graft fixation used by the surgeons is a stacked screw technique. The screws are helpful to shore up tunnels that have to be expanded while providing good holding power for the graft. Sometimes the old tunnel is filled in with bone and graft materials.
The authors discuss also how they determine the best angle for the tunnel and graft alignment. One method they use is with a guide pin. Details for prevention of injury to the nerve and joint cartilage while still getting inside the joint and putting the graft in the right position are outlined.
A variety of surgical options are presented and discussed for removal of the hardware left from the first surgery. Sometimes, it is possible to keep the old tunnels and hardware. The surgeon can either incorporate them into the new (revision) procedure or avoid and work around them.
Patients whose revision surgery ruptures (requiring a revision of the revision) are few in number. That's good for the patients. But the lack of data makes it difficult to guide surgeons in choosing the surgical technique that will yield the best results.
From the few studies already done, it's clear the results of a revision-revision are not as good as a successful first revision. Only a small number of athletes in this situation are able to return to sports at the level they were playing before the initial injury.
Anyone thinking about having anterior cruciate ligament reconstruction surgery must be advised that problems and complications can occur. The graft may fail completely for patient-related reasons or due to surgeon error. Most problems can be fixed but a second surgery may be necessary. Surgeons looking for advice from their colleagues on the treatment of a failed ACL graft will find the detailed information on technique in this article helpful.
Reference: Ganesh V. Kamath, MD, et al. Revision Anterior Cruciate Ligament Reconstruction. In The American Journal of Sports Medicine. January 2011. Vol. 39. No. 1. Pp. 199-217.