ORTHOPEDICS September 1, 2010

Failed ACL Repair

by Jon K. Sekiya, MD

In this issue of Orthopedics, Dr Sekiya discusses the causes and complications of failed ACL reconstruction and indications for revision ACL repair.

What are the causes of failed anterior cruciate ligament (ACL) reconstruction?

There are many causes of a failed ACL reconstruction, the most common being technical error with nonanatomic graft positioning. Other causes include failure to address secondary stabilizers, including other ligament injuries (posterolateral or posteromedial corner injuries), medial meniscus deficiency, limb malalignment or dynamic gait instability patterns, biologic and rehabilitation considerations, and re-injury.

What are the indications for revision ACL repair?

Indications for revision ACL repair would include symptomatic instability with activities of daily living or sports despite adequate rehabilitation.

What grafts do you use for revision ACL repair?

Jon K. Sekiya

I most commonly like to reconstruct a failed ACL repair with a double bundle ACL reconstruction using 2 tibialis anterior allografts. My partner Ed Wojtys frequently uses quadriceps tendon autograft due to the thick collagen fibers this graft offers and usual availability in revision cases. Both graft sources have worked well for us in revision ACL surgery. However, any of the other good, strong grafts are appropriate for revision ACL reconstruction including bone patellar bone autograft or allograft, hamstring autograft, or Achilles allograft.

What complications are associated with failed ACL repair?

Complications from a failed ACL repair include those associated with ACL injuries in general including meniscus tears, chondral injuries, decreased function, injury to other knee ligaments, and posttraumatic osteoarthritis. Other complications specific to a failed ACL repair include graft tunnel widening and loss of motion. Tunnel widening can be a difficult problem in revision surgery requiring staged bone grafting of the tunnels to prepare them for the revision ACL reconstruction. Loss of motion can be due to graft placement error or nonanatomic tensioning that may require graft removal in order to regain motion. This also often has to be staged with complete restoration of motion before attempting the revision ACL surgery.

Operative photographs of a patient undergoing revision double bundle ACL reconstruction with medial meniscus transplantation.

Is there any correlation between a delay in ACL reconstruction and a subsequent failure of said reconstruction?

In most opinions, immediate ACL reconstruction after injury is discouraged and many recommend a delayed reconstruction after appropriate rehabilitation to regain motion and decrease pain and swelling to avoid the risk of arthrofibrosis postoperatively. There have been a few newer studies that have challenged this paradigm. If you are asking about delaying a reconstruction for several months or years and in the interim playing twisting and pivoting sports, then the risk of meniscus/chondral injury increases. This does challenge the potential long-term outcomes of ACL reconstruction.

Does the rehabilitation differ with the revision ACL repair from the initial ACL reconstruction?

You could argue that going slower may make sense in a revision ACL reconstruction however the principles are the same. Early goals are to regain full extension/hyperextension, regain quadriceps control and strength, obtain full symmetrical range of motion to the other side, and to protect and control weight bearing without a limp. Later goals include obtaining full strength, agility, and proprioception with agility drills and functional training/rehabilitation before returning to sports.

What role does patient expectation play in the success of failed ACL repair?

Certainly patient expectations do play a role in the success of failed ACL repair. After 1 or 2 failures, there will usually be chondral and meniscal damage. Allografts may be used for reconstruction since primary autografts have already been used. This sets up all kinds of scenarios in terms of return to high impact sports and even the timing for return. In a scenario where the patient becomes meniscus deficient, we may be able to stabilize the knee, but from an impact loading perspective, this may not be the best situation to go back to high impact sports. While I routinely use allografts in my revision ACL reconstructions, patients are warned that they take longer to revascularize and become an ACL, as such, we need to rehabilitate them longer and give them time to heal. Expectations to return to play in 4 months are not realistic.

What does the future hold for ACL reconstruction?

I think there is a bright future for ACL reconstructions, as tremendous research is being performed by some of the best in our field. Biologic or regeneration techniques for ACL repair and reconstruction are on the horizon; we have come far already in terms of biomechanics and fixation strengths of various implants. In the ast decade, pioneers like Freddie Fu have preached the importance of anatomically reconstructing the ACL, double or single bundle, and this “anatomical concept” has no doubt led to a better understanding of where to put our grafts and tunnels and a shift for the better in how we reconstruct the ACL.

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