The Revolution in Joint-replacement Surgery
By Mitchell Kahn, MD

Here’s a medical term you’ll want to remember: MIS. It stands for minimally invasive surgery. And when it comes to joint replacements, MIS is very hip stuff… especially if your hip — or knee or ankle or shoulder — needs replacing. Here’s why:

Total joint-replacement surgery has been around since the 1960s. Back then it was pretty cutting-edge. Today, joint replacements are routine. Nearly half a million Americans underwent these procedures last year, saying goodbye to their aching, frozen joints and hello to a new lease on an active life.

It’s been an unqualified medical miracle — eh, well, make that one qualification: Joint replacements often require long recovery periods. In some cases, as long as three months. But that era may be drawing to a close with minimally invasive surgery. MIS means smaller incisions and far less trauma to muscles and tendons than the body sustains in conventional surgery. The result: Shorter, less painful recoveries and much smaller scars.

In surgery small = beautiful
Here’s how it works: The orthopedic surgeon makes incisions just large enough to insert the prosthesis. In fact, the incisions are so small that the surgeon must use a fluoroscopic x-ray or computer guidance technology in order to make sure the new implant is precisely installed. It’s pretty tricky business, which is why at this point only a small number of surgeons are considered truly skilled at MIS.

The medical profession is actually in a transition phase regarding MIS. While more surgeons are getting trained in the technique, university studies are underway to measure whether joint replacements done using MIS are as successful as those done using traditional surgery.

So far, the results are encouraging. And the future looks even brighter as advances in computer navigation systems make it possible for surgeons to place implants even more accurately despite the limited view afforded by the smaller incisions.

But because MIS isn’t yet a routine surgical technique — it actually takes longer to perform than conventional surgery — it cannot be conducted on all joint-replacement patients. Candidates must be in good health. Those who are obese (more than 30 percent over recommended body weight) or who have recently suffered a blood clot should probably avoid an MIS procedure. And it’s a bad idea for patients who have already had the same joint replaced. Believe it or not, being knock-kneed also may make this surgery a risk for you.

Ready for a new hip?
Now, if you think you’re a joint-replacement candidate, here are some tips you’ll want to keep in mind:
Find yourself a top-flight orthopedic surgeon. Whether you go with MIS or conventional surgery, the key to a successful joint replacement is picking the right surgeon to conduct this very complicated task. Do your homework. Experience is everything. You’ll want someone who performs the procedure at issue at least 25 times a year. And you’ll want it done in a hospital where the procedure is done at least 100 times a year.
Get the joint replacement done sooner than later. It used to be common practice for doctors to advise their patients suffering debilitating arthritis in their hips or knees to wait until the pain and immobility had grown intolerable. Nonsense. A recent Harvard Medical School study suggests that getting a joint replaced earlier yields long-lasting benefits. Breakthroughs in fabrication techniques have made artificial joints far more reliable and durable.

So what’s the point of waiting when joint replacements are in many cases expected to last 30 or 40 years? There is none. This safe, routine procedure is making life a lot more pleasant for hundreds of thousands of people each year. And as the state of the art improves, the prognosis looks even better.

Mitchell Kahn, M.D., is Assistant Clinical Professor of Medicine at Columbia Medical School and is Director of the Miller Health Care Institute at New York’s St. Luke’s Roosevelt Hospital.