Geriatrics

Jordana Bieze Foster

Most older adults with severe knee osteoarthritis report significant improvement in physical function a year after undergoing a total knee replacement. But according to research from the University of Delaware, those patients don't know what they're missing.

Using data from the National Longitudinal Study of Adolescent Health (known as Add Health), researchers from the University of North Carolina, Chapel Hill evaluated 4,142 adolescents in seventh through twelfth grades in September 1995 and reassessed them in April 2002. Using the data from that The participants were screened to be sure they did not exhibit signs of depression at the start of the study.Depressive symptoms were assessed using a nine item standardized depression screen in the first and final years of the study.

The Delaware study suggests that quadriceps strengthening after a total knee procedure, which is not part of most rehabilitation protocols, can improve functional performance enough to rival that of healthy older adults. The added strength is essential for such activities as stair climbing, and could help forestall the eventual declines experienced by most patients in the second decade after surgery.

"Why undergo a $25,000 elective surgery and then not do as much as you can to get the most out of it and improve your quality of life?" said Lynn Snyder-Mackler, ScD, PT, ATC, professor of physical therapy at the university and senior author of the study. "Our study demonstrates that intensive strength exercise as outpatient therapy is critical to begin three to four weeks after surgery."

Snyder-Mackler and colleagues assigned 200 patients to one of two six-week exercise programs four weeks they each had had unilateral total knee replacement surgery (also called total knee arthroplasty). Both exercise programs emphasized progressive quadriceps strengthening; one also incorporated neuromuscular electrical stimulation (NMES) of the quadriceps femoris muscle.

Patients from both groups completed functional performance tests prior to starting the program and at three and 12 months postoperatively. In addition, 41 patients who had the same procedure performed by the same surgeon but declined to be part of the intervention were tested at baseline and 12 months. Those 41 patients underwent rehabilitation consistent with the local standard of care, which emphasized range of motion exercises, stationary cycling, and straight-leg raising exercises without weights.

At 12 months, the individuals in the two quadriceps strengthening exercise groups did significantly better than the standard-of-care patients on a timed walking test, a stair climbing test, and a distance walking test. In fact, the test scores associated with quadriceps strengthening in the Delaware study were similar to the scores of healthy individuals in several previous studies.

In the Delaware study, all three groups had similar outcomes for pain, knee range of motion, and--interestingly--self-reported function, suggesting that those in the standard-of-care group thought they were more functional than they actually were. However, the researchers found no added benefit of the NMES. The findings were reported in the February 15 issue of Arthritis & Rheumatism.