Q&A Topic: Boning Up On A Common Knee Injury

Evan H. Karas, MD, FAAOS

Q. What exactly happens when the ACL tears? Is it a common injury?

A. Attaching the tibia (shinbone) to the femur (thighbone) at the knee, the anterior cruciate ligament (ACL) is one of the most important stabilizers of the knee, preventing it from rotating abnormally or extending too far. But, when certain movements stress the ligament beyond its capacity, it tears in two. The injury is most common in people who play sports, especially those involving quick changes of direction or "cuts," primarily basketball, skiing, football, and soccer. It occurs when the foot is planted and you push off to change direction, twisting the knee.

Q. I’m on the women’s soccer team at my college. Am I at risk for an ACL tear?

A. A tear to the ACL is extremely common, but females are at four to six times greater risk of tearing the ACL, due to their anatomy. In addition, playing on artificial turf might add risk. It’s important to wear proper shoes when playing on this surface. You're more likely to get stuck on turf; whereas, you’ll probably slide on grass, and the knee won't twist as violently.

Q. What symptoms indicate an ACL tear?

A. The top three symptoms that, together, indicate an ACL tear about 90 percent of the time are a twisting injury to the knee, hearing a pop (as the ligament tears), and rapid swelling. Any knee injury associated with swelling and significant pain should be evaluated by an orthopedist.

Q. Is there anything I can do to protect myself from an ACL tear?

A. Specific physical therapy programs reduce the likelihood of an ACL tear and can train you to move in ways that better support the knees. One focus is equalizing the strength of the muscle mass in front of the thigh (quadriceps) with that in back (hamstrings), which is often weaker. It’s also possible to modify your landing techniques. Many ACL injuries occur when people land stiff-legged, rather than on the ball of the foot in a stable, balanced position. An orthopedist can steer you to a physical therapist who is knowledgeable about these training methods.

Q. What are the treatment options for a torn ACL?

A. Treatment options are either conservative, that is, non-surgical; or surgical reconstruction. Conservative measures are appropriate for those without a high activity demand, and whose knee is not giving way during activities of daily living. Treatment might involve wearing a brace, and typically includes physical therapy to strengthen the knee muscles and restore motion. However, though the pain from the injury does not last, a torn ACL never actually heals. As a result, if this key stabilizer is not reconstructed surgically, the knee can remain unstable or wobbly.

Surgical approaches all involve re-creating the ligament, rather than repairing it. Often a new ACL is created from tissue graft from the person's own knee. Northern Westchester Hospital was one of the first hospitals in the region to introduce a new surgical procedure called the all-inside ACL reconstruction. The minimally invasive technique preserves the integrity of the shinbone, which results in many benefits. When choosing a surgeon to perform the procedure, it’s important to find a board-certified orthopedic surgeon who has done a fellowship in Sports Medicine.

Q. What are the advantages of the all-inside procedure?

A. Because the shinbone is structurally preserved, patients experience far less post-surgery bruising, swelling, and pain, and are able to walk unassisted far sooner. Traditionally, patients were on crutches for two to three weeks. Now, it’s possible to walk unassisted as soon as one week or less. Also, the titanium device used to attach the ligament is stronger than the traditional screws, which may lower the incidence of grafts loosening over time. But, despite the faster recovery, this new procedure doesn’t mean a faster return to sports. The biology of the knee's healing process needs to be respected. Most people return to sports that involve cutting six to seven months after surgery. The all-inside procedure is appropriate for anyone eligible for ACL surgery. 

Northern Westchester Hospital
Co-Chief, Orthopedic Surgery
Co-Director, Orthopedic & Spine Institute
Learn More About Dr. Karas


‚ÄčWatch an animated video on knee surgery

More from Dr. Karas: Shoulder Pain and Advanced Shoulder Surgery


‚ÄčNorthern Westchester Hospital is a proud member of Northwell Health (formerly North Shore-LIJ Health System).

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