Anterior Cruciate Ligament (ACL) Tears

with Michael Gordon, M.D., Orthopaedic Surgery, Columbia St. Mary's

Posted: April 1, 2004

Knees. Over the course of a lifetime they get skinned, scraped, and used – an awful lot. Routine trips and falls generally require little more than peroxide, a little antibiotic ointment and an adhesive bandage. But for the one in 3,000 Americans who end up with a tear to their anterior cruciate ligament (ACL), over-the-counter remedies are not a viable solution.

“The ACL functions like the center post that everything rotates around,” said Dr. Michael Gordon, a surgeon with Columbia St. Mary’s who specializes in sports medicine and orthopaedic surgery.

Michael Gordon, M.D., Orthopaedic Surgery, Columbia St. Mary's "Joint sense, or proprioception, is the ability of your brain to get signals from all the joints involved in an activity. By properly training yourself to reflexively respond to at-risk positions, you can help to prevent an injury to the ACL."

The ACL is one of four ligaments holding the knee in place; one on either side to stop the bones from sliding sideways, and the ACL and posterior cruciate ligaments (PCL), which cross over the knee in the middle to keep the bones from sliding backwards (PCL) or forward (ACL). The ligaments work in concert with the cartilage, meniscus and thigh muscles to provide stability.

ACL tears are caused by either too much forward motion of the shin bone (tibia) under the thigh bone (femur) or by too great of a twisting motion. Only 33 percent of all ACL injuries are the result of contact; the remaining two-thirds, said Dr. Gordon, are theoretically preventable.

Prevention tips
The best way to do that, said Dr. Gordon, is by making sure you’re in good shape, particularly if you’re involved in athletic activities involving cutting-type maneuvers such as skiing, soccer, basketball and football.

New designs in skis and cleats are helping reduce the number of ACL injuries, Dr. Gordon said. He cited improved binding and boot designs for skiers and, for soccer and football players, a cleat shaped like a comma rather than the traditional circular design.

“The increased rotation of the foot and lower leg protects the knee a little more by taking the stress off of the ACL,” he said of the cleat design. Additionally, newer versions of artificial turf provide more of the “give” associated with natural turf, decreasing the stress on the entire leg.

For women, the increased risk factors are a function of gender-related factors.

People whose exercise habits are not as rigorous or regular also can reduce their risk of ACL tears by improving their joint sense and knowing how to land in case of a fall.

This is especially true for older athletes and women, who have a two-to-four times higher incidence of ACL tears than the general population.

For women, the increased risk factors are a function of gender-related factors.

“First and foremost, the ACL seems to be smaller in women, even when you correct for body weight,” Dr. Gordon said. “Also, the thigh muscles provide less support for the knee in women. Several recent studies have clearly shown that men are able to provide much greater stiffness and stability across the knee relative to women. In terms of overall alignment, a woman’s leg tends to be a little more knock-kneed than a man’s, which puts her into a slightly greater at-risk position.”

One thing women can do to reduce their risk of ACL tears is improve their landing technique. Studies have shown that women have poorer landing techniques than men, significantly increasing stress on the ACL.

Surgery isn’t the only solution for someone with an ACL tear, Dr. Gordon said.

Dr. Gordon said that “several pre-season conditioning programs focusing on this issue at the college level have shown great improvements in preventing ACL injuries.”

Treatment
Surgery isn’t the only solution for someone with an ACL tear, Dr. Gordon said.

“There are no problems returning to simple activities with a well-rehabilitated leg with occasional brace use,” he said. Non-surgical interventions include modifying activities, strengthening the hamstring and quadriceps muscles in the legs, joint sense training and using a knee brace when needed.

Surgery is advised, however, if a patient wants to return to playing cutting-type sports or performing activities such as climbing up and down a ladder, all of which require good knee stability.

With arthroscopic reconstructive surgery using grafts from cadavers or through self-donation by the patient, 90 to 95 percent of patients are able to resume pre-injury activities once fully recovered from the surgery.

Dr. Gordon prefers cadaver tissue, acknowledging that there is a controversy regarding that choice. For patients who are not comfortable with that route, he can use grafts from the patient’s own body, such as two hamstring tendons or a portion of patellar tendon.

In either case the graft is analogous to taking a piece of yarn and weaving it into the knee. The body will accept the new tissue and ultimately join the new and old structures together so that the graft functions like a native ACL.

But, Dr. Gordon said, there are costs to using a patient’s own tissue. “There has been a greater focus on the use of cadaver tissue recently and we are continuing to improve our graft preparation techniques. Regardless of the type of graft chosen, we are now able to get reliably good results in terms of knee function and stability as well as in the ability of a patient to return to his or her desired sport or activity.”

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