Relief for arthritic knees

Sep 25 2007

If you're among the estimated 10 million Americans who have been diagnosed with osteoarthritis of the knee, take heart in knowing that several nonsurgical options, pharmacologic and otherwise, are available for easing the pain of an arthritic knee, according to Cleveland Clinic's Arthritis Advisor.

In addition to the judicious use of nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids, options include weight control, leg-strengthening exercises, and the use of assistive devices, such as a cane or walker.

According to Robert Molloy, M.D., an orthopaedic surgeon at Cleveland Clinic, another option for many patients is a knee brace—a device, either soft or rigid, that is worn around the knee to provide support and reduce excessive loading on a damaged joint.

The knee comprises three components: the medial compartment (on the inside of the joint), the lateral compartment (on the outside), and the patellofemoral compartment (the area behind the kneecap). Knee braces are primarily recommended for patients whose loss of knee-joint cartilage is “unicompartmental”—that is, confined to only one of these three compartments. “The devices are most frequently prescribed in cases involving the medial compartment, since that is where OA most often develops,” says Dr. Molloy.

The simplest type of brace is a one-piece sleeve made of an elastic rubber—neoprene—that fits snugly around the knee area. Appropriate for use by patients with relatively mild OA, these sleeves, available over the counter at most pharmacies, compress the affected area, providing warmth and a moderate amount of support. “Some patients, especially those who are comparatively active, may benefit from wearing one of these devices,” says Dr. Molloy.

“Sleeves may decrease pain, and a fair number of patients claim that to be the case, but we don't really know why, since these devices don't have any structural effect on the joint.”

Of greater value for patients with more advanced knee OA, says Dr. Molloy, is an “unloader” brace—a semi-rigid device made of molded plastic and foam, with reinforcing steel struts on each side to limit the knee joint's lateral movement.

“It's a custom-fit brace that's most often prescribed for people with arthritis in the medial compartment,” he says. “When some people with arthritis in this part of the knee walk, you can actually see the knee wobble toward the inside. It's not dangerous, but this wobbling—called a varus thrust—can be painful.

“The unloader brace is designed to provide three points of pressure on the thigh bone, which forces the joint to bend away from the inside of the leg. In effect, it relieves pain by transferring pressure from the inside part of the knee to the outside part.”

Although unloader braces are used primarily by patients with OA in the medial compartment, a brace also can be designed to increase mobility and reduce pain stemming from cartilage destruction in the lateral compartment, allowing the patient to walk more rapidly and for greater distances.

In addition to easing moderate to severe pain, unloader braces are often prescribed as a temporary source of relief for those with advanced cartilage damage who will ultimately need to undergo joint-replacement surgery. “Some patients,” notes Dr. Molloy, “can get along quite well for six to 18 months before the brace is no longer effective and they have need for surgery.”

Unloader devices are unique in structure and differ significantly in purpose from other types of braces that are commonly found in pharmacies and sporting-goods stores. A “prophylactic” brace, for example, is designed to prevent injury to an arm or knee. A second category includes “rehabilitative” braces, which are designed to be worn by someone who has had a recent injury or surgery involving the ligaments in the knee joint. A third category includes “functional” braces, which are designed to help control abnormal motion in an unstable knee. Unloader braces, for people whose knee instability is the result of cartilage loss, fall into this third category.

“You'll need a prescription from an orthopedic specialist in order to purchase an unloader brace,” says Dr. Molloy, “and you'll need to purchase it at a store that specializes in orthotic devices, where they will construct the brace so that it delivers the proper amount of force to the joint. ”

Obtaining maximum benefit from wearing an unloader brace, which may not feel comfortable at first (it may take a week to a month for you to get used to how it feels on your leg), will require a certain amount practice. And although Dr. Molloy says “The more you wear a brace, the better it works,” he urges patients not to neglect other important therapeutic measures, such as exercises to strengthen the muscles surrounding the knee (see below). Also be wary of over-reliance; wearing a brace all the time doesn't permit exercising and strengthening your leg muscles.

The only “drawback” of an unloader brace, he says, is that it tends to be bulky, making it difficult for a patient to wear one, for example, under a pair of snug-fitting slacks. Furthermore, he adds, unloader braces tend to be relatively expensive, typically priced to $500 or more. However, Dr. Molloy points out, most health insurance providers will partially cover the cost of a brace.

What You Can Do

If you're considering a knee brace:

• Consult an orthopaedic specialist on the potential value of using such a device.
• Don't expect a brace to feel good from the start. It may take weeks before it feels comfortable.
• Don't become over-reliant. Wearing a brace all the time doesn't permit exercising and strengthening of the muscles surrounding the knee.
• Don't neglect your other therapies, no matter how well the brace works.