October 3 (HealthDay News) -- Despite the desire to return to athletic activity after hip or knee replacement, patients tend to reduce their activity following their surgery, researchers say.

In a study published in the October issue of The Journal of Bone & Joint Surgery, researchers reviewed the latest data on athletic activity after joint replacement.

Hip and knee replacement surgeries are very successful in relieving pain and improving function in people with arthritic joints. Pain relief has traditionally been the primary reason people consider joint replacement, but with the aging of the baby boomer generation, many people are also looking to improve their joint function.

"Baby boomers have lower tolerance for discomfort and disability if they are involved in athletics," Dr. William L. Healy, an orthopedic surgeon at Lahey Clinic in Burlington, Mass., said in an American Academy of Orthopaedic Surgeons news release. "After joint replacement, they often want to be able to keep up the same level of sporting activity that they enjoyed in the past."

But there is evidence that participating in strenuous athletic activity after joint replacement can cause stress and wear on the new joints, leading to inflammation, fluid build up, pain, and the wearing out of the artificial joint.

Since past research on sports and total joint replacement is lacking, it is still not clear how much activity should be recommended following hip or knee replacement.

"We need to keep in mind that surgeons and patients often assess the success of joint replacement differently," said Healy. "Surgeons look at pain, function, and survivorship, and whether the patient needed revision, while patients consider their pain and activity. If the joint allows them to play their favorite sport without pain, they may not be concerned about needing an additional surgery in the future."

People who have had a knee or hip replacement and want to play sports should train for the sport, build their back, hip, and knee strength, and keep in mind the potential risks of activity after the joint replacement.

SOURCE: American Academy of Orthopaedic Surgeons, news release, Oct. 1, 2008