Reported June 2006

BACKGROUND: The University of Pittsburgh Medical Center is using an innovative new approach to repairing one of the most common sports knee injuries: the torn anterior cruciate ligament (ACL).

ABOUT THE KNEE: The knee is made up of three bones designed to produce smooth, stable motion: the shinbone (tibia), the thighbone (femur) and the kneecap (patella). The bones are enclosed in the joint capsule, which is lined with a tissue that produces a thick liquid to keep the joint lubricated and nourished. The knee is kept in alignment by ligaments and tendons. The anterior cruciate ligament is one of two major stabilizing ligaments of the knee joint. The other one starts at the back of the knee -- the posterior cruciate ligament. These two ligaments cross each other at the center of the knee. There is another set of stabilizing ligaments on either side of the knee as well, which stabilize the joint when the knee moves from side to side.

WHEN GOOD JOINTS GO BAD: A healthy knee bends easily, absorbs stress and glides smoothly so we can walk, squat, or turn without pain. When the knee is damaged, it is less able to handle stress, causing pain and swelling. The anterior cruciate ligament (ACL) is one of two major stabilizing ligaments of the knee joint. Injuries to the ACL are the most common. Often there is a loud pop -- the sound of the ligament tearing -- followed by pain and immediate swelling. After those symptoms subside, the patient may still experience episodes of instability, often likened to walking on roller skates. The knee may feel loose. In serious cases, surgical repair may be required.

WHAT'S NEW: The ACL has a complex structure consisting of two different bundles. Most ACL repairs use a single-bundle reconstruction technique that uses metal or plastic screws to graft on tendons or tissue taken from healthy parts of the knee. These single bundle reconstructions have a success rate of 70 percent to 90 percent. UPMC's new double-bundle technique restores the natural complexity of the knee, using tendons from another donor rather than hamstring tendons taken from the patient's own leg. Researchers believe the new double-bundle technique could result in even higher successful recovery rates, with the same rehab period. Both surgical approaches are followed by immediate physical therapy and protective bracing and crutches for the first few weeks. Light sports activities may be resumed after three months, with a return to contact sports around nine months later.

If you would like more information, please contact:

Department of Orthopaedic Surgery
Johns Hopkins Outpatient Center
Baltimore, MD
(410) 955-3870

FACTOID...

The average person will use his knee joint over 1 million times per year.