A Guide to Knee Replacement Surgery

The science behind knee replacement surgeries has become more advanced. The procedure itself is on the rise, with about 600,000 procedures performed annually.

"Good Morning America" medical contributor Dr. Marie Savard explains the latest developments in knee replacement surgeries below.

Click to learn more about knee replacement procedures.

Possibly Preventing Knee Replacements

Using a patient's own cells to re-grow damaged tissue works for patients who've had injuries playing sports or an accident, rather than the natural deterioration that comes with age.

This procedure is done when the cartilage that cushions the joints in the knee is damaged. This experimental procedure takes a piece of the remaining healthy cartilage out of the knee and literally grows new tissue outside the body. Then the healthy tissue is re-inserted.

Someone with this knee damage would be looking at a partial or total knee replacement, which we're always looking to avoid. That's the upside. The downside is that the procedure is costly and has a long recovery time: the patient can't bear weight on the knee for 6-8 weeks, and could take up to a year to fully recover. In time, however, costs will go down and the technology may improve so that the recovery time will be decreased.

Partial Knee Replacement

Over the last ten years, the number of partial knee replacements has increased nearly 33 percent.

The partial knee replacement is minimally invasive and involves less bone and soft tissue involvement, which means there is less blood loss during surgery and fewer incidents of complications. It also means considerably less pain and a much quicker recovery period for the patient.

But there is a catch. A partial knee replacement requires some very delicate surgery.

In a partial knee replacement, damaged bone is removed, basically smoothed away. It's critical that the alignment is done just right. Smoothing away too much bone — or too little — negatively affects the fit and can cause serious problems for the patient. However, there's a new tool, a robotic arm that can be used with addressing the medial or inside portion of the knee. Using a computer and 3D calculations, the arm can be set precisely in a practically foolproof way. It won't let the surgeon make a cut in the wrong direction. It all leads to a more precise fit for the implant.

Same-Day Total Knee Replacements

This is another minimally invasive technique that is appropriate for a small number of knee patients. In order for patients to go home the same day, they must be healthy, fit and not on any medications.

The surgery itself takes about two hours and physical therapy begins the same day. Since the quadriceps tendon is not cut, the patient can recover two- to three times more quickly.

Some surgeons are in favor of this same-day procedure because recovering from home is often safer, because it lowers the risk of infection. Others believe everyone deserves an overnight stay for pain control.

I think that we'll see that the future is computer-assisted, partial knee replacement surgery that's minimally invasive.

Gender Specific Knee Implants

First, more women than men get knee replacements, so if there's a size issue at all, is should be addressing men's implants rather than women's. That said, these implants are not one-size-fits-all. Every artificial knee is fit to the individual person.

Find out more about the MAKO robotic arm at www.makosurgical.com.