• Posted July 18, 2022

Repair or Reconstruction: What's Best for ACL Tears?

Adults who tear a key ligament in the knee can fare well with a less extensive type of surgery, preliminary research suggests.

The study involved patients treated for a ruptured anterior cruciate ligament (ACL), a strong band of tissue that helps stabilize the knee joint. ACL tears commonly happen during sports that involve jumping or sudden stops and pivots, like basketball, soccer and skiing.

The injury is often treated with surgery, and the "gold standard" is ACL reconstruction: A surgeon removes the torn ligament remnant and replaces it with a portion of a tendon from elsewhere in the body, or with donated tissue from a cadaver.

For many years, reconstruction has been the preferred choice over repairing the tear in the existing ligament. Studies going several decades back showed that those repaired ligaments often did not hold up over time.

"Historically, repair was associated with poor results," said lead researcher Dr. Adnan Saithna, an orthopedic surgeon at AZBSC Orthopedics, in Phoenix, Ariz.

But repair techniques have been modernized, he explained, and there is growing interest in offering ACL repair to at least some patients.

Both ACL reconstruction and repair are minimally invasive procedures, done via small incisions, but repair is thought to have some potential advantages. It avoids borrowing tissue from a patient's tendon (usually a tendon connecting to the kneecap or one of the hamstring muscles), and it might allow a faster recovery.

But, Saithna said, there has not been much data on how modern ACL repair stacks up against reconstruction.

For the study, his team compared 75 patients who'd undergone ACL repair at one medical center with 75 patients who'd had a standard reconstruction. Each repair patient was "matched" with a reconstruction patient of the same age, sex, body weight, sports participation and general physical activity level.

"So we compared patients who were very similar to each other," Saithna said.

Overall, the study found, repair patients did better in certain respects: Six months after surgery, they had better hamstring strength. And farther out - 2.5 years, on average - they typically had better scores on a "forgotten joint" scale: Essentially, they were giving less thought to their injured knee, possibly because it felt normal again.

There was a significant downside, however. Repair patients were more likely to re-injure the joint: 5% suffered another ACL tear, while none of the reconstruction patients ruptured their ligament replacement.

Age did seem to make a big difference in that risk: Many repeat tears were among patients younger than 22.

According to Saithna, the age divide makes sense. High school and college athletes, eager to get back into the game, may simply have more chances at a re-rupture. He added, though, that the risk might partly stem from the biology of those younger knees, too.

As for whether repair led to a faster recovery, the study found no clear proof of that: 75% of repair patients had returned to their pre-injury level of sports participation, versus 60% of the reconstruction group - but that difference was not significant in statistical terms.

Saithna presented the findings Saturday at the annual meeting of the American Orthopaedic Society for Sports Medicine, in Colorado Springs, Colo. Studies reported at meetings are generally considered preliminary until they are published in a peer-reviewed journal.

Dr. Andrew Pearle is chief of the Sports Medicine Institute at the Hospital for Special Surgery, in New York City.

He called ACL repair "an important tool to have in our armamentarium." But he cautioned that the risk of re-injury in young patients should be taken seriously.

"For young athletes, repair has what I consider an unacceptable revision rate," said Pearle, who was not involved in the study.

A repeat rupture, he noted, can damage other tissue in the knee - including cartilage cushioning the joint.

On the other hand, Pearle said that for adults who are not heavily into "cutting" sports, like soccer and basketball, ACL repair can be an option.

But there is also another choice for the relatively older, non-athletic crowd: Physical therapy, without surgery.

Pearle said that some people are "copers." That is, their knee joint is stable enough for their usual activities, even without an ACL. Other, not-so-lucky people are "non-copers," and without an ACL they end up with a "trick knee" that routinely buckles. (Unfortunately, Pearle noted, there's no way to predict which patients will be copers.)

One question the new findings do not address, Pearle said, is how ACL repair compares against physical therapy alone for relatively older patients - say, age 30 and older. That would be a valuable study, he said.

At this point, many people who suffer an ACL tear may find their surgeon does not even put repair on the table. "It's not currently mainstream," Saithna said.

But like Pearle, he said that a go at physical therapy is "perfectly reasonable" for the relatively older person who is active but not an athlete.

More information

The American Academy of Orthopaedic Surgeons has more on ACL injuries.

SOURCES: Adnan Saithna, MD, orthopedic surgeon, AZBSC Orthopedics, Phoenix; Andrew Pearle, MD, chief, Sports Medicine Institute, Hospital for Special Surgery, New York City; July 16, 2022, presentation, American Orthopaedic Society for Sports Medicine annual meeting, Colorado Springs, Colo.