A surprising new study reveals that prehabilitation before a total knee replacement (TKR) may not significantly improve the results of the surgery. The findings contradict previous research and the approach used by many orthopedic surgeons who assign specific exercises for their patients in the weeks prior to the TKR operation.

“This randomized clinical trial found no evidence that multidisciplinary prehabilitation before TKR for osteoarthritis improves short-term functional independence or reduces midterm activity limitations after surgery,” said Dr. Christelle Nguyen, of the Cochin Hospital, University Center in Paris, who led the study and published the findings in JAMA Network Open.

According to Medscape, previous research has demonstrated that patients who are in good health fare better after knee replacement surgery. A few small studies have shown that physical therapy, exercise therapy, occupational therapy, and education either alone or in combination can improve outcomes and shorten the time a patient needs to spend in the hospital.

For her research, Nguyen studied 178 women and 84 men with a mean age of 68.6 years who were candidates for surgery because of worsening osteoporosis. They were divided into two groups. One group received standard advice from their surgeons and an information booklet.

The second group received the same advice and information but were assigned to rehabilitation education and exercises starting two months before their surgery. According to Medpage Today, the “prehab” consisted of four 90-minute sessions which included 30 minutes watching an educational slideshow followed by 60 minutes of exercise.

The exercise program focused on strengthening the quadriceps, lateral knee stabilizers and hamstrings. It also included leg stretches, improving knee posture and balance and practicing postoperative maneuvers such as transferring from supine to sitting, sitting to standing and standing to sitting.

After surgery and following standard care, the study subjects were evaluated for short-term function by four tests:

•Supine to sitting

•Sitting to standing

•30-meter walk

•Ascending and descending a flight of stairs

Four days after surgery 27% of the control group, who did not do have rehabilitation, and 34% ― not significantly more ― of the group that had prehabilitation were able to perform these basic functions.

Researchers said that one drawback of the study is that only 197 patients did the short-term testing and only one-third of the patients attended the supervised prehab sessions.

Nguyen and her colleagues acknowledged that the prehab program may have too burdensome for some patients as evidenced by the number of participants who skipped sessions. They suggested that a more simplified, home-based rehabilitation program would have been more effective.

Dr. Bert Mandelbaum, a professor of orthopedics at Cedars-Sinai Kerlan-Jobe Institute in Los Angeles, told Medscape: “As far as I can see there’s no way to determine what the people were doing or not doing in the control group.”

Clinicians should recommend exercise to their patients before surgery, he said. “It’s just common sense.”