By Pat Anson, Editor

A new study by British researchers has come to the surprising conclusion that physical activity such as walking and climbing stairs does not increase after hip replacement surgery.

Total hip replacement is one of the most common elective procedures. The surgery is usually performed on the elderly to relieve pain from osteoarthritis, which causes a loss of cartilage and joint function.

But in the first systematic review to examine the differences in physical activity both before and after hip replacement, researchers were left questioning the purpose of the surgery.

"The most common reason for a hip replacement is to reduce pain on movement. We expected that the amount of physical activity post-surgery would therefore increase. What we found surprised us," said lead researcher Tom Withers, from the University of East Anglia’s School of Health Sciences.

Withers and his colleagues looked at the physical activity of over 1,000 patients who had hip replacements, analyzing how far and how fast they walked, as well as cycling and climbing stairs.

"We found that there was no clear evidence of a change in physical activity following surgery,” said Withers. "The benefits of regular physical activity following a hip replacement are well known, so this research is important for healthcare professionals because it suggests that patients need to be encouraged to be more physically active."

The research findings are being published in the journal Clinical Rehabilitation.

"The lack of significant difference in physical activity after patients undergo such a common procedure suggests there is a need for further research, including further investigation into how other personal characteristics or pre-existing conditions might also influence the results,” says Toby Smith, a lecturer in physiotherapy in UEA's School of Health Sciences.

"Healthcare professionals and researchers need to better understand this lack of change and how patient's perceptions of physical activity might be modified to increase their engagement in physical activity post-operatively."

Recent studies in the United States have questioned whether many joint replacement surgeries are appropriate. A five year study of 175 knee replacement patients by the National Institutes of Health found that over a third of the surgeries were inappropriate. Many patients had pain and other symptoms that were too mild to justify having their knees replaced.  

About 30 million Americans have osteoarthritis, including a growing number of younger patients, aged 40 to 65. Doctors are often reluctant to perform hip replacement surgery on patients under age 50 because prosthetic joints typically last for less than 20 years. A second surgery to remove a worn prosthetic can destroy bone and put patients at risk for infection and other complications.