David Attarian, MD

Medicine is not immune to the seductions of tradition -- there are studies to prove it. “A lot of things that we do in medicine, we do because we’ve always done it, not because there are good data to support that practice,” says orthopaedic surgeon David Attarian, MD, who knows firsthand how difficult it can be to break “bad habits” in practice.

Knee replacement surgery has, for the past 30 years, made use of continuous passive motion (CPM) to aid recovery in patients.

The CPM machine -- a device that requires a fair amount of effort on the part of the nurse, therapist, or family member to put it on the patient without hurting the patient -- came into popularity after some data showed that it might help reduce drainage and increase a patient’s range of motion at discharge (which was, at that time, seven to 10 days after surgery).

Attarian estimates that CPM machines are still in use in as many as half of hospitals that perform total joint replacement. “Some hospitals use it as a way to control costs, because it reduces their need for therapists to be on hand,” he says. Moreover, patients have come to expect the CPM -- they hear previous patients talking about how it helped them recover, and they think they need it.

But here’s the thing -- current data don’t support it. Over the past 10 years, hospitals that specialize in total joint replacement have studied the use of CPM versus moving a patient rapidly into active therapy, says Attarian, and they’ve found that it is no better for a patient than introducing physical therapy shortly after the surgery.

Evidence-Based Care at Duke Orthopaedics

Duke’s Total Joint Coordination of Care Committee has developed a new protocol regarding knee replacement surgery. Instead of CPM, the patient receives his or her first physical therapy visit on the day of the surgery (or the following morning), and his rehabilitation focuses on active motion instead of passive.

Attarian led a Duke study of the protocol, and the results mirrored the data gathered at other institutions -- leaving out CPM reduces patient pain and resource drain by cutting out the burden of applying and removing the device, which requires two people and four to six hours’ worth of labor over the course of a day. And the patients have the same outcomes at discharge and three months out, compared to results from CPM patients.

While it took some time to convince patients and doctors alike, Attarian says, the protocol is now used 100 percent of the time at Duke.