As a minimally invasive procedure, total joint arthroplasty has been making headlines. Given the demand for new joints - hundreds of thousands of knee and hip replacement surgeries are performed in the United States each year - the patient population undoubtedly exists. Plus, the procedure's benefits are obvious. If you can recover faster, with a significantly smaller incision, less muscle and tendon trauma and less pain - why wouldn't you choose a minimally invasive over a conventional joint replacement?

Total joint arthroplasty has even been touted as a prime candidate for addition to ambulatory surgery centers. Pioneering surgeons describe patients out of their beds and on their way home on the day of surgery. Richard Steinfeld, MD, FAAOS, an orthopedic surgeon and partner at the Orthopedic Center of Vero Beach in Vero Beach, Fla., is more skeptical on that front. Performing minimally invasive joint replacements on an outpatient basis is still "pretty much a rarity," he says, noting that while it's feasible, it's not yet practical for many reasons.

Surgeons who have undertaken the procedure say the technical demands can present a learning curve that may initially lengthen the procedure's OR time, though a skilled practitioner can do it in an hour or slightly more.

"It's a change in mindset and, like anything else, it's in getting comfortable with it," says Dr. Steinfeld, who also notes that the success of the minimally invasive method depends heavily on patient selection: their previous medical history, their potential for complications, whether they've had previous joint surgeries or deformities and even their musculoskeletal build.

Given that the procedure involves insertion between muscles and tendons and not cutting through them, Dr. Steinfeld points out that, for instance, larger, male patients with denser musculature - usually prime candidates for surgery - might not prove as easy to operate on as thinner women with more flexible muscles.

While outpatient joint replacement surgery would significantly reduce facility fees by removing the costs of a hospital stay from the equation, the hospital costs are what Medicare and other healthcare insurers demand.

In terms of minimally invasive versus conventional procedure costs, insurers "see it as knee replacement, whether it's a 12-inch or a three-inch incision. That doesn't matter to them," says Dr. Steinfeld.

But because there's no ASC code for total joint arthroplasty, insurers essentially demand it be done in the hospital, which results in a three- to five-day stay and perhaps five days or more in a rehabilitation center as well, although healthier patients may be discharged directly home from the hospital.

To a certain extent, a post-op hospital stay is an issue of cautious patient care. "Most of the talk about minimally invasive total joint replacement involves a stay in rehab," says Dr. Steinfeld, noting concerns over the possibility of blood clots or patients who may not have around-the-clock assistance at home.

Even Dr. Steinfeld's partner at the Orthopedic Center of Vero Beach, David Griffin, MD, FACS, FAAOS - the first surgeon in Florida and one of the first in the United States to perform a total knee replacement in a surgery center setting ("How We Did Total Joint Replacement Surgery At Our ASC," page 56, January/February 2000) - wasn't exempt from these obstacles.

Dr. Griffin's groundbreaking 1997 procedure was performed on a German man in his late 60s who'd traveled to the United States for the surgery. The patient, who wasn't insured, paid the cost out-of-pocket, and the procedure relied on the surgery center's alliance with a nearby acute care rehabilitation hospital, where the patient was transferred after surgery.