Knee Injuries
Aug 2008
As a competitive athlete, I constantly hear about ACL injuries. Who is at risk for this type of injury and what is the standard treatment?
One of four main knee ligaments, the anterior cruciate ligament (ACL) is a primary stabilizer of the knee. Both the anterior and posterior cruciate ligaments are located deep inside the knee and prevent the shifting of the upper and lower leg bones during physical activity. The other two knee ligaments, called the collateral ligaments, are located on the inside and outside of the knee, and they also help keep the knee stabilized.
Tears of the ACL are common sports injuries. Although many people associate ACL injuries with a hard tackle or blow to the knee, the majority (60 percent) of ACL injuries are not caused by physical contact. Among those 25 years of age and older, about half of all ACL injuries occur while skiing.
ACL injuries are usually described as sudden knee pain when the knee “gives way” after a sudden twist or hyperextension. One-third of people who suffer this type of injury hear a “pop” when the ligament tears—often so loud that others nearby can hear it.
During a physical exam, patients with ACL injuries exhibit forward motion of the lower leg bone (tibia) relative to the upper leg bone (femur). Obtaining radiologic images of the knee will often help the doctor make a diagnosis and rule out other knee injuries, such as those of the meniscus, which refers to the cartilage surrounding the knee joint. People with ACL injuries will notice that their injured knee “gives out” or feels unstable when they participate in activities such as basketball, football, baseball, tennis or skiing. These individuals can usually participate in alternative activities such as jogging, biking, swimming and weight-lifting, as well as use a treadmill or elliptical trainer. Some people, however, may have problems with day-to-day activities following an ACL injury.
Initial treatment of an ACL injury requires rest, ice, elevation and relying on crutches as necessary until the acute symptoms subside. Exercises to improve range of motion in the knee, often performed with the help of a physical therapist, should begin soon after the injury as pain allows.
Successful treatment of ACL injuries depends on many factors including a patient’s age, desired activity level and associated injuries. For young, active patients, ACL reconstruction surgery offers the best chance of a successful return to competitive sports. For older individuals who participate in more “straight-line” activities such as running, walking and swimming—which are less dependent on the stability of knee movement in all directions—a less aggressive treatment plan that includes physical therapy and knee bracing may be recommended.
ACL reconstruction is an arthroscopic procedure generally done on an outpatient basis. Surgeons can choose from multiple sources of graft material to replace a damaged or torn ligament. The tissue used to make the repair may come from either the patient’s own hamstring tendon or from tissues in the front of the knee. The latter option could include portions of the kneecap (patella), the tendon in front of the knee (patella tendon) and the tibia, all removed as one unit (a procedure called the “bone-tendon-bone” graft). Another option, which is less traumatic to the patient, is to use a donated ligament in a tissue transplant.
Although the incisions are small, a successful ACL reconstruction requires a patient’s commitment to the rehabilitation process, which involves vigorous physical therapy initially to regain motion, progressing to strength training. For a patient to return to playing sports, he or she will likely need a minimum of four months of intense therapy as well as evidence of the muscle strength needed to get back in the game.
Dr. Jon H. Swenson is a board-certified orthopedic surgeon practicing with Hampton Roads Orthopaedics and Sports Medicine in Newport News. He is a member of the American Academy of Orthopaedic Surgery, the Virginia Orthopaedic Society, the Medical Society of Virginia and the Newport News Medical Society.