Osteoarthritis is increasingly common among aging Americans and is the leading cause of disability in the U.S. Exercise is often used in treating osteoarthritis and is an important part in rehabilitation following joint replacement. The level of function prior to knee and hip replacement has been shown to be strongly related to function after surgery, yet little is known about the effects of exercise on patients with end-stage osteoarthritis. A study published in the October 2006 issue of Arthritis Care & Research (http://www.interscience.wiley.com/journal/arthritiscare) examined whether an exercise program prior to hip or knee replacement would benefit patients in terms of function, pain, and muscle strength before or after surgery.
Led by Daniel S. Rooks, ScD of New England Baptist Hospital, Beth Israel Deaconess Medical Center and Harvard Medical School in Boston, MA, the study included 108 patients scheduled to undergo hip or knee replacement between November 2001 and November 2003. The patients were divided into two groups: 54 patients participated in water and land-based exercise three times a week for the six-week period immediately before surgery and 54 controls received educational materials. Prior to surgery all patients were questioned about their level of function and were evaluated in terms of lower-extremity strength, balance, and mobility. The exercisers participated in strength training, aerobic and flexibility exercises that were individually tailored to each person's fitness level, performed in a group and supervised by a physical therapist.
The results showed that patients who exercised reduced their odds of discharge to an inpatient rehabilitation facility by 73 percent. "The potential economic implication of this finding is noteworthy and should be examined in future studies, particularly with the rise in inpatient rehabilitation use," the authors note. The exercisers were also more likely to walk more than 50 feet at the time of hospital discharge. Those who exercised responded differently before surgery and immediately following surgery depending upon the joint replaced: although patients who exercised increased lower-extremity muscle strength, only those undergoing hip replacements showed improved function before surgery.
"Our findings show that an appropriately designed program of water and land-based exercise involving cardiovascular, strength training, and flexibility activities can be a safe, well tolerated, and effective approach to improving function and muscle strength in middle-aged and older adults with severe osteoarthritis of the hip and knee," the authors state. They point out that patients participated in strength training for only 3 weeks (9 sessions), which is well below the recommended duration required to bring about significant strength gains. They suggest that the increase in strength was due to a combination of increased neuromuscular coordination and a reduction of fear about anticipated pain associated with increased muscular effort. They note that knee replacement patients would probably need to participate in strength training for a longer period of time in order to experience increased function prior to surgery.
The fact that the patients responded differently depending upon what joint was being replaced suggests the need for different approaches for people with osteoarthritis of the hip and knee. Also, because several participants who dropped out of the study did so because of the travel required to get to the group exercise location, the authors suggest that future studies should consider the location and convenience of the exercise sessions. They conclude: "Additional attention should be placed on testing postoperative interventions for building on preoperative gains in function and fitness, adapting the intervention more successfully for the TKA [knee replacement] population, and examining the cost effectiveness of exercise for patients undergoing total joint replacement."
Contact: Amy Molnar
John Wiley & Sons, Inc.