Treatment Guide: Knee Replacement

Five ways to put the spring back in your step

When deterioration of the knee joint gets so bad that you have bone rubbing on bone, and medication, physical therapy or steroid injections no longer help the pain, the next step is a joint replacement. Dr. Bob Booth of 3B Orthopedics at Pennsylvania Hospital, who personally does about 400 of the nation’s half-million annual knee replacements, calls them “one of the big success stories in medicine,” with a 98 percent success rate ten years down the line and a 94 percent success at 20 years out. A top-notch orthopedist like Booth can replace a knee in under half an hour. Two good criteria when choosing your surgeon are the length of the surgery and the number they’ve done.

[sidebar]Here are your options:

Conventional knee replacement: An 8- to 11-inch incision is made through the muscles and tendons of the knee and a metal and plastic artificial joint is inserted in place of the worn one. Expect a three- to five-day hospital stay, up to a week of in-patient rehab followed by extensive physical therapy, and as much as six months to heal. Despite that, this classic, tested approach is still the most widely used because it practically guarantees excellent results.

Minimal (small) incision total knee: This giant leap in knee replacement came to the fore in 2004, opening the possibility of new knees for a younger, more active population. While the joint itself is the same as in a conventional knee, the surgical technique is vastly different. Using a small three- to five-inch incision, the surgeon removes sections of joint bit by bit and eliminates cuts through the major muscles and tendons that power the knee.

Advantages: Recovery from a minimal knee replacement is about one-third faster than a conventional, and there’s less pain because more of the knee structure remains intact. Patients leave the hospital in two days and go directly home or to a brief rehab stay. Canes are tossed in less than a month. Studies show that function and longevity are as good as or better than conventional knees when done in the right hands. At Virtua Health in Voorhees, Dr. Scott Schoifet is offering healthy, active, under-55-year-old mini-knee candidates an overnight or even out-patient option. “It’s much less costly to the health system,” he says “and really lessens the risk of picking up a hospital-based infection.”

Disadvantages: “Minimal incision is far more technically challenging and difficult than conventional. It takes longer and requires a whole specially trained team,” notes Pennsylvania Hospital orthopedist Dr. Jess Lonner, a mini-knee pioneer who has done 1,000 of them. “The skill of the surgeon is critical.”

Partial knee: If you’re young and active and your arthritis pain is limited to one of the knee’s three compartments, you might want to consider fixing only the damaged third. Partial knee surgery preserves the healthy bone and saves the major ligaments. While England’s been doing it for 15 years, it’s been less popular here because it’s not easy to do and may not eliminate the need for a total in the future.

At the 2008 orthopedic convention, everyone was wild about a new robotic-assisted system for partial knees. Pennsylvania Hospital is one of eight sites in the country testing it. Dr. Jess Lonner did the procedure on a 62-year-old man, who was riding his bike and mowing the lawn a week after surgery. Ask your doctor about it.

Gender knees:
Traditionally knee replacements came in varied sizes. Now there are knees shaped and contoured for different situations — left leg, right leg, Asians and females. Women, for instance, have a wider pelvis and a narrower knee than men, and the angle where the leg bone meets the knee cap is different. The gender knee is made to more naturally fit their anatomy.

The OtisKnee: “This is the knee of the future!” declares Bryn Mawr orthopedic surgeon Dr. Joe Vernace. Just a year ago he was one of 12 doctors in the country using OtisKnee technology. Now there are more than 400. Previous advancements in knee replacement centered around improvements in the size, shape and material of the joint. The OtisKnee is a computer-assisted technique that revolutionizes the surgery itself. In simplified terms, a California company takes a MRI image of the knee and creates 3-D computer models of the previously healthy and now damaged knee. From these, they develop a patient-specific, plastic cutting guide that shows the surgeon precisely where to cut the bone and at what angle to insure a fit that perfectly matches the patient’s own anatomy. “Patients are off a walker in a week,” says Vernace, “and in a month, 80 percent no longer need a cane. But even better, the new knee feels as normal as the original.”