When an anterior cruciate ligament reconstruction (ACLR) needs to be revised, surgeons are faced with numerous challenges, including the following:

• removing the hardware implanted during the primary ACLR procedure
• avoiding previously drilled tibial and femoral tunnels
• selecting the most appropriate graft type for the patient
• managing patient expectations after revision surgery

During his presentation at the 2014 American Orthopaedic Society for Sports Medicine Specialty Day, Darren L. Johnson, MD, professor and chairman of the department of orthopaedic surgery and director of sports medicine at the University of Kentucky School of Medicine, covered these and other steps orthopaedists can take to achieve good patient outcomes after revision ACLR.

Dr. Johnson has performed a high volume of revision ACLR surgeries, often on patients younger than 25 years who were injured while playing sports that require cutting and pivoting, such as basketball, football, skiing, and soccer.

Preparing for revision ACLR
Before performing revision ACLR, the orthopaedic surgeon should first consider reasons why the primary graft may have failed, so that similar issues can be avoided during the revision surgery.

“Consider whether the graft type and the athlete were mismatched, or whether alignment issues played a role,” said Dr. Johnson. Recurrent trauma or a too-early return to sport after primary ACL reconstruction are other potential reasons for primary graft failure.

He stressed the importance of a detailed patient examination, including gait analysis.

“If the patient has varus/valgus thrust on heel strike while walking, and you don’t eliminate that during surgery, that’s going to be a problem,” noted Dr. Johnson.

Although the patient may arrive with multiple sets of radiographs and MRI scans, the most important things to review, in Dr. Johnson’s opinion, are the operative report from the primary ACL reconstruction surgery, arthroscopic pictures from that surgery, and current, high-quality plain radiographs, including an alignment film.

“I won’t schedule a patient for surgery unless I have the operative report from the first surgeon and current radiographs,” said Dr. Johnson. “If the films show a significant amount of tunnel lysis, for instance, or if they show that the patient’s medial meniscus has been removed, they can be very important in planning the surgical approach.”

Pearls for surgery
Graft selection plays an important role in patient outcomes. Dr. Johnson uses large autografts (approximately 10 mm to 12 mm in diameter) in young revision patients because the literature indicates that large autografts have a lower failure rate in young athletes. Data suggest that large autografts—which are associated with lower costs and readily available—also incorporate earlier in revision ACLR patients.

“The tools the surgeon will need during the revision procedure depend on the previously implanted hardware,” noted Dr. Johnson. “That is one reason for reviewing the operative report prior to revision surgery—to ensure all the tools required for the procedure are in the operating room.”

As for surgical technique, Dr. Johnson recommends outside-in ACL femoral drilling.

“I do most of my drilling on the femur now, outside-in, with the knee at a 90-degree flexion angle. Approximately 98 percent of the time, I can avoid that previous tunnel and can instead drill a virgin femoral tunnel, avoiding the need for a staged procedure. Generally, I can also avoid the need for staged surgery when drilling the tibial tunnel, since it’s possible to drill right through a screw, if necessary,” he said.

“Probably the most important step in revision ACL is to make sure the graft is in the right place,” said Dr. Johnson. “I try to place it center-center, below the intercondylar ridge on the femur, in the center of the tibial footprint.”

The surgeon often must also treat the other involved structures during revision surgery, asserted Dr. Johnson, noting that procedures such as osteotomy of the femur or tibia, meniscal allograft reconstruction, and collateral knee ligament surgery may be necessary.

“If a patient has an absent medial meniscus, a meniscal root tear, or an abnormal thrust on his or her gait, for instance, the surgeon needs to address the issue during the surgery; otherwise, the revision will fail,” said Dr. Johnson. “Meniscal allograft reconstruction in the revision situation can be critically important, particularly on the medial side.”

Although tools such as bone dowels can be used to avoid the need for staged procedures, some revision cases do require a staged procedure. Dr. Johnson cited one of his cases, in which the patient required staged surgery due to a completely absent medial meniscus associated with tunnel lysis greater than 15 mm.

“On this patient, I initially performed a medial meniscal allograft reconstruction as well as a bone graft. I performed the revision ACLR 3 months later,” he said.

Finally, noted Dr. Johnson, managing patient expectations is one of the most important tasks related to revision ACLR.

“I tell the patient from the beginning that recovery from revision ACLR is a 9- to 12-month process,” said Dr. Johnson. “If the patient asks why we need to go so slowly, I say it is because I don’t want to have to perform a third ACL surgery.”

Disclosures: Dr. Johnson—Smith & Nephew, Smith & Nephew Endoscopy, DJ Orthopaedics, Elsevier, Journal of Surgical Orthopaedic Advances, American Orthopaedic Society for Sports Medicine, Southern Orthopaedic Association.

Jennie McKee is a senior science writer for AAOS Now. She can be reached at mckee@aaos.org

Bottom Line

• Prior to ACLR revision surgery, orthopaedic surgeons should review the operative report and arthroscopic photos from the primary ACLR surgery and recent plain radiographs, including an alignment film.
• Based on the literature, large autografts (10 mm to 12 mm diameter) are recommended for young revision patients, due to their lower failure rate.
• Using an outside-in femoral drilling surgical technique can help avoid the previously drilled tunnel and thus avoid a staged procedure.
• Revision ACLR surgery should also address other involved structures with procedures such as osteotomy of the femur or tibia, meniscal allograft reconstruction, and collateral knee ligament surgery.
• Surgeons should counsel patients that rehabilitation after revision ACLR may take 9 to 12 months and that returning to play too soon could result in the need for another revision ACLR.