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Knee News

Brace for Knee Arthritis Gets an 'A'

There are many different types of braces on the market for the knee. Prophylactic braces are used to prevent or decrease the risk of a knee injury. Functional braces stabilize a wobbly knee when the anterior cruciate ligament (ACL) is deficient or after surgery to repair the ligament. Rehabilitative braces limit the amount of knee motion that's allowed during recovery and rehab after knee surgery. But the focus of this article is on the unloader (sometimes called offloader) brace used to give patients with osteoarthritis pain relief.

The off-loader brace just got rated an A for consistent, good-quality patient-oriented evidence based on a review of the literature. All evidence points to the use of off-loader braces as a good way to improve knee stability while reducing knee pain. How do these braces work? Well, first of all, they are meant to be used by patients who have unicompartmental knee osteoarthritis. Unicompartmental arthritis affects one side of the joint (usually the medial side -- the side closest to the other knee).

Unicompartmental knee osteoarthritis is a common problem associated with alignment problems, obesity, and aging. Some people have a slightly inward angle at the knee that results in more weight being placed on one side of the knee. It could be a valgus angle, which is more toward a knock-kneed position that leads to lateral unicompartmental osteoarthritis. Or (more commonly), it could be a varus angle, a bow-legged position resulting in medial unicompartmental osteoarthritis. Either of these two malalignment problems causes cartilage degeneration and ligament laxity, bringing the joint surfaces closer together. The result is an increased load on one side of the joint.

The unloader or off-loader brace uses adjustable straps and pads to apply an external force to distract the involved compartment. It's a mechanical intervention meant to reduce pain, which in turn, increases function. The long-term goal is to keep the arthritis from getting worse. By improving the alignment of the knee, compressive force and load are shifted off the already damaged area of the joint.

It's expected that with an estimated 27 million adults with osteoarthritis, that this brace will used by more and more patients in an effort to avoid (or put off) a knee replacement. There are predictions that nearly half of the American adult population will develop knee pain from osteoarthritis. The rising rates of obesity make this almost a certainty. With no cure in sight, every method shown to benefit osteoarthritis is worth knowing about.

The last time the effectiveness of off-loader bracing was reviewed (2005), there weren't enough good quality studies to provide evidence that this treatment was safe and of any benefit to patients. Since that time, new evidence has shown a much higher percentage of evidence for their effectiveness.

Who should use this type of brace? Management guidelines published by the American Academy of Orthopaedic Surgeons (AAOS) suggest that adults with pain and activity limitations because of pain should be considered for an off-loader brace. X-ray evidence of unicompartmental knee osteoarthritis is required. Patients who meet these criteria who have not been helped with standard medical care are likely good candidates for this type of bracing. Standard first-line medical treatment includes nonsteroidal antiinflammatories, steroid injections, and viscoelastic supplementation.

Age is another important criteria in the use of off-loader bracing. Adults 65 and older are the main target group. Younger, more active adults may be better candidates for a surgical procedure called a tibial osteotomy. In this procedure, a wedge-shaped piece of bone is removed from one side of the tibia (lower leg bone) and inserted on the other side of the tibia. This realignment procedure shifts weight away from the diseased side. By doing it when the patient is younger, there's a better chance that unicompartmental disease can be avoided.

What are patients saying who are using this brace about their results? Questionnaires evaluating knee pain and function show that the majority of carefully selected patients who use the off-loader report significant improvement in pain and function. They can walk longer and climb stairs with greater ease. Many patients were able to double their pain free walking time from an average of 51 minutes before bracing to 138 minutes with bracing. Improvements in daily function continue throughout the first year of wear. Patients were also able to reduce the amount of pain medication taken each day when using the brace.

There were some studies that did not show an overall benefit from bracing. Patients were able to get some pain relief but their function and quality of life did not improve over time. Others found that the benefits only lasted as long as they wore the brace. Patient compliance dropped over time, possibly contributing to a decline in perceived benefit.

There's still plenty of room for further study in this area. Research is needed to find the optimal knee alignment using the brace. Should the knee be exactly in neutral? Or is that too much stress in the opposite direction from where the natural knee rests? If neutral isn't used, how many degrees of valgus or varus would give the best results? Does wearing the brace for 12 months put off surgery by an equal number of months? Is it necessary to wear the brace during all daily and sports activities? Or can it be worn just during periods of increased physical activity and exercise? These are just a few of the many questions yet to be answered.

The authors conclude that there is new evidence that supports the use of an off-loader brace as a cost-effective way to treat unicompartmental knee osteoarthritis and delay surgery. Patients report decreased pain, better stability, and fewer falls. The overall level of evidence from analysis of all the updated data puts the strength of this recommendation at 76 per cent for the success of off-loader braces treating unicompartmental knee osteoarthritis. The higher the percentage, the higher the strength of the recommendation based on scientific evidence.


Dan K. Ramsey, PhD, and Mary E. Russell, MS. Unloader Braces for Medial Compartment Knee Osteoarthritis: Implications on Mediating Progression. In Sports Health. September/October 2009. Vol. 1. No. 5. Pp. 416-426.

09/17/2009

*Disclaimer:* The information contained herein is compiled from a variety of sources. It may not be complete or timely. It does not cover all diseases, physical conditions, ailments or treatments. The information should NOT be used in place of visit with your healthcare provider, nor should you disregard the advice of your health care provider because of any information you read in this topic.
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