Anterior Cruciate Ligament (ACL) tears are one of the most common sports injuries requiring surgery, and now ACL reconstruction can be tailored to the individual.
Improved surgical techniques are more anatomically precise than previous procedures, according to a sports medicine expert at Baylor College of Medicine.
“The details of how we treat ACL tears have become very individualized based on a number of factors, most importantly the patient’s own ACL anatomy,” said Dr. Theodore Shybut, assistant professor of orthopedic surgery at Baylor.
Other important considerations include age, activity level, associated or prior knee injuries and individual patient preferences.
Understanding the injury
The ACL is a ligament in the central part of the knee that stabilizes the knee during cutting and pivoting activities, such as changes in direction and landing from jumps, and other agility movements.
According to Shybut, 70 percent of these injuries are non-contact injuries.
“It happens when an athlete’s body is going one way and he or she plants a foot to change direction. Their momentum carries them one way and the knee twists and the ACL tears. A classic example is when basketball or soccer player makes a cut, they hear or feel a pop, and their knee buckles. It often swells quickly, and the knee gives way when they try to pivot again,” he said. “Many athletes are surprised to learn that you can walk normally on your knee when the swelling has resolved. If you’re doing activities that don’t involve change of direction, your knee might feel OK.”
Reconstructing ACL tears
Although it is possible to function without an ACL, it’s extremely difficult to return to high-level sports without it. If one’s activity level is very low demand, sometimes using a brace and undergoing rehabilitation to strengthen muscles that support the knee and the body can be sufficient treatment.
However, ACL reconstruction is still the recommended and most reliable treatment for those who want to get back to sports activities that involve cutting and pivoting, said Shybut. Surgery is also recommended for those who fail a trial of non-operative management and often for those who have concurrent knee injuries.
Another major concern with non-surgical treatment is if individuals have further episodes of the knee giving way. Something else has to take up the force that an ACL would normally absorb, and the meniscus in the knee is often the next in line because it is a secondary stabilizer. Those who go back to athletics without an ACL have higher rates of medial meniscal tears and, the longer they delay reconstruction, the injuries become more complex and can become irreparable.
Breaking down the surgery
Surgery involves making a new ACL with a graft – typically a tendon, sometimes with attached bone, that is threaded through bone tunnels into the knee joint, and fixed into place. The body uses the graft as a scaffold and grows into it to make a new ACL. The tissue can either be from a person’s own knee or from a donor, most often a cadaver.
Three common types of grafts used in ACL reconstruction. Each have different pros and cons, and depending on each individual there are reasons to argue for or against different graft choices.
“Previously, the tunnels that are drilled into the knee for the surgery have not been as anatomically precise. In recent years, the surgery procedure for ACL tears has become more refined in terms of placing the tunnels in a better anatomical position; they reflect our enhanced understanding of ACL anatomy and function. The end result, we think, is that these anatomic ACL reconstructions can better resist those rotational forces that the native ACL is supposed to resist,” said Shybut.
The procedure used to involve drilling one tunnel and then putting the drill through that tunnel to drill the other tunnel. This causes one tunnel to be constrained by the other and forces both to work at a more upright configuration.
Now, the procedure involves drilling the tunnels independent from each other, with the goal of getting better long-term results from reconstruction.
“It’s become a very individualized procedure with regard to choosing the graft that fits the patient, sizing it specific to their knee and placing the ACL graft where their native ACL was,” said Shybut.