At a Glance 

• ACL reconstruction restores stability but does not eliminate the risk of PTOA.
• Nearly half of patients develop radiographic osteoarthritis within 10 to 15 years of ACL injury and reconstruction.
• Long-term joint health, not simply return to sport, should define success after ACL surgery.

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Editor’s note: The Final Cut is a recurring editorial series written by a member of the AAOS Now Editorial Board.

The true hardship of an anterior cruciate ligament (ACL) tear isn’t a missed season, a lost college athletic scholarship, or an abrupt end to a sports career. The real tragedy is the 35-year-old parent who struggles to comfortably jog or participate in their children’s active lives. It is the 30-year-old who faces chronic knee pain and a total knee arthroplasty at age 45.

When we reconstruct an ACL, we are using a mechanical solution for a complex biochemical and biomechanical trauma. The initial injury triggers an immediate inflammatory cascade that permanently alters the environment of the knee, only to rear its head in half of cases 10 to 15 years later as post-traumatic osteoarthritis (PTOA).

Athletes and their parents often are understandably devastated by the news of an ACL injury, and it is hard to focus on much beyond the immediate future, surgical counseling, and recovery timelines during those early clinic visits. Even so, I try to also picture these young athletes 20 years in the future. I want them to reap the physical and mental health benefits of sports participation and exercise. I would love for them to score goals, win championships, and maintain their athletic identity. But I also want them to be able to go on a hike, run after their kids, and preserve mobility as they age.

As surgeons, we strive to lower our ACL retear rate with return to sport, with a focus on technical aspects (graft selection, tibial slope, and addition of a lateral extra-articular tenodesis or anterolateral ligament reconstruction), attaining quantitative rehabilitation metrics, and improving athlete confidence. ACL surgery is often deemed a success when a player returns to sport (especially at the same level) and does not retear their graft for at least two years. But the longer I am in practice and the longer the follow-up, the stronger I feel that ACL reconstruction should not be judged by games played or trophies won the following two seasons, but rather by the health and comfort of the joint two decades down the road.

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Related Content 

• AAOS Anterior Cruciate Ligament Injuries Clinical Practice Guideline (AAOS resource) 

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I recently saw one of my own ACL postoperative patients about a decade after her surgery. She was 14 when she tore her ACL. She is 23 and recently graduated from college, where she played lacrosse. She started training for a marathon and noticed her knee was swelling and sore at the inner aspect. She had no reinjury. I knew what the images would show, and there it was: early medial compartment degenerative changes with tiny marginal osteophytes.

Her graft was intact and looked beautiful, well positioned. Her knee was stable. Her cartilage was generally thinner than expected for her age throughout the knee. Her knee was OK as long as she did not run. There is no way to reverse her early PTOA, and she and I are left with options usually reserved for a 50-year-old person with early knee arthritis who may someday need a knee replacement.

In addition to prioritizing and advancing research efforts to prevent post-traumatic arthritis, we must adopt three fundamental principles in how we treat, counsel, and care for these patients.

Address the entire biology of the joint
The health of the meniscus and articular cartilage is paramount. Saving the meniscus alone has not proven sufficient to prevent PTOA, but it is worthy of our efforts. We must also manage the postoperative inflammatory cascade Ñ hopefully with growing tools to do so in the future. I regularly aspirate knees postoperatively to eliminate the hemarthrosis, due to the known chondrotoxicity of blood in the joint. Biologic research in this area is evolving, and we must continue to evolve our practices.

Redefine shared decision making for return to sports with joint longevity in mind
Patients should be educated on the risk of reinjury with return to high-risk sports and the risk of PTOA inherent in the initial injury. A patient may meet timelines, pass rigorous functional testing, and demonstrate greater than 90% limb symmetry but have a persistent mild effusion with high-impact activity. These symptoms should be discussed as a sign of potential overload of the physiologic envelope of the postoperative knee. Another teen athlete may have a poor score on the ACL Return to Sport after Injury questionnaire (ACL-RSI) but excellent objective measures of adequate rehabilitation. Does this teen need further rehab, a sports psychologist to overcome fear of return to play, or acknowledgement that fear of reinjury (a real possibility) is logical? Choosing alternative forms of physical activity or lower-risk sports should be recognized as a reasonable form of self-preservation.

Lead with empathetic, honest counseling
We owe our patients empathy and absolute honesty. We must explain that while surgery restores stability, return to sport is not without reinjury risk, and protecting their long-term joint health requires a lifetime of neuromuscular maintenance, weight management, and, in some cases, activity modification. We tell patients that surgery stabilizes the knee and reduces the risk of future meniscal injury, but how many of us share that 50% of patients develop radiographic osteoarthritis within 10 to 15 years of ACL reconstruction? Patients deserve this information.

It is important to ascertain the goals of our patients and help them achieve those goals in the safest possible way, but it is also important to educate them about the long-term health of their knees. We need to prioritize longer-term follow-up and research on reducing the risk of PTOA. It is time to change the measuring stick of a successful ACL operation. Our patients deserve a success story that extends beyond two years and hopefully lasts a lifetime.

Jocelyn Wittstein, MD, FAAOS, is an orthopaedic surgeon specializing in sports medicine and an associate professor at Duke University School of Medicine in Durham, North Carolina.