Improving Results of ACL Repairs

Sometimes surgery fails. Fortunately, this doesn’t happen very often. In the case of anterior cruciate ligament (ACL) repairs, a second operation is needed when the first one fails.

Studies show that the results of the revision ACL reconstruction (RACLR) aren’t as good as the first operation. The original surgery is referred to as primary ACL reconstruction (PACLR).

In this report, surgeons from the Vanderbilt Sports Medicine Center in Tennessee review how and why PACLR fails. They describe technical and diagnostic errors and offer suggestions for ways to improve outcomes. A very useful flow chart is provided for the surgeon when preparing to do a RACLR.

Loss of motion and scarring are the most common complications after PACLR. Less often, poor surgical technique or too little or too much rehab can lead to poor muscle function or knee instability. Sometimes athletes return to sports too soon. The ACL graft has not healed or rehab has not been completed. The knee isn’t able to respond to stress when there’s still a loss of neuromuscular control. In such cases, traumatic reinjury leads to PACLR failure.

Errors in how the surgery is done are the most common cause of ACL graft failure. For example, the donor graft may be damaged when it is harvested or when it is implanted. The graft may be put in the wrong place or with the wrong amount of tension (too loose or too tight). The surgeon creates a tunnel through which the graft is threaded. Tunnel placement must be just right to prevent problems from the wrong amount of graft tension.

In order to avoid increased loads on the PACLR, the surgeon must make sure all surrounding soft tissues are intact. Any other damage to the ligaments, joint capsule, or cartilage must be repaired during the first operation.

When a revision operation is needed, the surgeon must examine the patient carefully before surgery. The surgeon must decide what to do with fixation devices used in the first operation. Some can be reused. Others must be removed. The size, shape, and placement of the tunnel may need to be changed.

In the future results of both PACLR and RACLR may be improved by identifying risk factors for failure. Knowing the risk factors will help surgeons take steps to avoid problems by choosing the right procedure for each patient.