A carefully structured exercise program after knee replacement offers no advantages over less intensive care, a randomized clinical trial has found.

Australian researchers studied 422 people ages 45 to 75 who had undergone total knee replacements. Half were randomly assigned to receive standard rehabilitation services, usually involving about six sessions of physical therapy over six weeks.

The others were sent home with a sheet of exercise instructions for the first six weeks, and then received eight weeks of treatment with twice-weekly physical therapy classes that included warm-up and cool-down exercises, functional and strengthening routines and 20 minutes of aerobic exercise each session. The study is in Arthritis Care and Research.

After a year, there were no significant differences between the two groups in stair climbing power, walking speed, knee strength, range of motion, pain, adverse events or re-hospitalizations.

“Seventy percent of the whole cohort got more than a 50 percent reduction in pain, and at 12 months had function good for their age,” said the lead author, Marlene Fransen, an associate professor of physiotherapy at the University of Sydney. “But you need to keep going more than a year to increase muscle strength. Otherwise you’re setting yourself up for trouble later on.”