ACL update: Lubrication key to preventing osteoarthritis after injury
The researchers used animal models with torn ACLs to test 3 types of fluids that could be injected into the joints to serve as a substitute for lost synovial fluid: human synoviocyte lubricin that was created in a culture and then purified to be
Options for restoring lubrication in the knee after injury to the anterior cruciate ligament (ACL) to prevent the development of osteoarthritis (OA) were identified in a recent study conducted by researchers at Rhode Island Hospital, Providence. Noting that synovial fluid concentration of the natural lubricant, lubricin, is significantly lower in a knee after a traumatic injury to the ACL than in a healthy, uninjured joint, researchers sought to identify biologic methods to address the loss of lubricin and avoid the increased risk of posttraumatic OA.
The researchers used animal models with torn ACLs to test 3 types of fluids that could be injected into the joints to serve as a substitute for lost synovial fluid: human synoviocyte lubricin that was created in a culture and then purified to be injected into the injured knees; recombinant protein, with a change in the genetic makeup of the cell so that it makes a molecule of interest; and lubricin from human synovial fluid that otherwise would be discarded (a positive control). Lubricin was found to be the most effective form of lubrication for limiting cartilage deterioration, although the recombinant form also was successful. The study results also indicated that when lubricin is placed back into the traumatized joint, it encourages the joint to make its own lubricin.
The researchers suggested that the study findings represent a paradigm shift in arthritis prevention and management and that further studies will contribute to improved technology and prevention efforts. The study was published in the August issue of Arthritis & Rheumatism and was available online ahead of print at http://www.rheumatology.org.
An estimated 200,000 ACL injuries occur in the United States each year, according to The American Journal of Sports Medicine, the official publication of the American Orthopaedic Society for Sports Medicine (AOSSM). New study results reported at the AOSSM’s recent annual meeting include the following:
•The jury is still out on the effectiveness of prevention programs for knee injuries in young athletes, and better-designed research studies are needed before it can be determined that ACL and knee injuries may be prevented with specialized training programs.
•A new in-office tool may provide physicians with a low-cost alternative to expensive in-laboratory identification of athletes at high risk for ACL injury. The simplified method combines measuring the tibia or shin bone with a standard measuring tape and an athlete’s weight and capturing motions of the knee during landing with standard camcorders. This method may be used as a training camp protocol in partnership with team clinicians or set up and run in the athletic training setting. Women are 2 to 8 times more likely to injure their ACL than men, according to recent studies.
•Secondary knee injuries in children-more than 7300 meniscus tears and 7800 cartilage tears in the United States each year-could be avoided with early rather than delayed ACL reconstruction surgery.
In addition, close to $30 million would be saved in annual hospital charges.
For more information about the AOSSM or its STOP Sports Injuries campaign, visit the AOSSM Web site at http://www.sportsmed.org. For a discussion of reducing obesity and the risk of knee OA, go to www.musculoskeletalnetwork.com to see “Quick steps to reducing obesity and knee osteoarthritis” [“Article Archive,” May 27, 2010].
