Surgical treatment of hip or knee arthritis does not reduce obesity

Feb 27 2005

A number of arthritis sufferers attribute their weight gain to inactivity due to a painful hip or knee. These patients may be disheartened when their post-operative weight either remains the same or increases.

A study presented during the 72nd Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS) dispelled the common public misconceptions that osteoarthritis leads to obesity and that the surgical treatment (joint replacement) of this disabling joint disease leads to patient weight loss.

Osteoarthritis -- or degenerative joint disease -- is one of the most common types of arthritis, and is experienced by nearly 21 million Americans. Characterized by the breakdown of the joint cartilage, osteoarthritis causes bones to rub against each other, leading to pain and loss of movement. Obesity is a risk factor for both the development and progression of knee and hip osteoarthritis. Many of the 500,000 U.S. patients each year that receive total hip and total knee replacements are overweight or obese. This adversely affects the patients' overall health, and may compromise the lifespan of the prosthesis. Thomas P. Schmalzried, MD, orthopaedic surgeon at the Joint Replacement Institute, Orthopaedic Hospital, Los Angeles, and a team of researchers conducted a study to determine if successful treatment of hip or knee arthritis with total joint replacement leads to weight reduction.

Researchers recorded the change in body weight after successful total joint replacement in 34 males and 66 females between the ages of 23 to 82. In follow-up with patients at least one year after their procedures, data revealed that total hip and total knee replacement patients gained an average of 1.2 kg (almost three pounds) post-surgery. There was no difference in weight gain between total hip and total knee replacement patients. Surprisingly, the younger hip replacement patients and patients with single joint disease gained the most weight after surgery.

Accumulating evidence indicates that the successful treatment of lower extremity arthritis does not lead to weight loss. "This study clearly demonstrates that osteoarthritic patients are unlikely to lose weight after joint replacement surgery," said Dr. Schmalzried. Many patients misplace the blame for their weight gain onto their painful joint. Total joint replacement is not the solution to achieve weight loss, advised Dr. Schmalzried. "The medical community should recognize and treat obesity as the independent disease that it is and not attribute it solely to inactivity from arthritis, but from other lifestyle factors," he said. Orthopaedic surgeons and primary- care physicians need to clearly communicate preoperatively with patients regarding their weight and their expectations following joint replacement surgery.

"For osteoarthritic joint replacement patients to have the best chance of losing weight post-surgery," Dr. Schmalzried said, "we recommend that they change their diet to reduce the total caloric intake and adhere to a regular exercise program that includes at least 20 minutes of aerobic activity three times per week. The key component is to simply stay with the program."

AAOS suggests the following tips for starting and maintaining a safe and effective exercise program, post-surgery:

• Check with your physician first for advice on what types of exercise you should, or shouldn't do.
• Be sure to warm-up before doing any exercises. Begin with slow, rhythmic activity like walking, gradually increasing the intensity until your pulse rate, respiration rate and body temperature are elevated.
• Follow the ten percent rule. Start any activity in short bouts, gradually adding no more than a 10 percent increase, as you are ready.
• Drink lots of water. When you begin exercising, your body requires even more fluid. Don't wait until you are thirsty to drink. It may also be beneficial to eat smaller meals throughout the day.
• Wear appropriate athletic shoes with proper support and comfort.
• Choose activities that you enjoy and can perform consistently to maintain your regimen.

An orthopaedic surgeon is a physician with extensive training in the diagnosis and non-surgical as well as surgical treatment of the musculoskeletal system, including bones, joints, ligaments, tendons, muscles and nerves.

http://www.aaos.org/