Hip and Knee Joint Replacement : Surgical Skill and Techniques

by Food and Drug Administration (FDA)

(Page 4 of 4)

Surgical Skill

Choosing the appropriate prosthesis is only one part of the equation for successful hip or knee joint replacement. "The most important factor in joint replacement success is the surgeon," says Greenwald. "The first question I'd ask the surgeon is, 'How many have you done and what are your complications?'"

Jonathan Garino, M.D., agrees. "There are a number of good devices out there," says Garino, an orthopedic surgeon with the University of Pennsylvania Health System. "But even if you have the best technology in the world, it has to be implanted correctly." It falls to the surgeon to put the device in right, but it falls to the patient to take care of the new joint, says Garino. Regular exercise is important, but high-impact activities, such as running and jumping, generally are discouraged.

The independent panel convened by the NIH in December 2003 to study total knee replacements also concluded that proper surgical technique was one of the most important factors leading to successful knee replacement. Studies have found that the more knee replacements a surgeon performs, the lower the rates of complication, according to the panel. Similarly, complication rates fall in hospitals with increasing numbers of operations performed.

Surgical Techniques

While prosthesis makers are changing designs, materials, and manufacturing methods to try to lengthen the life of artificial knees and hips, surgeons are refining techniques or developing new ones to try to improve the outcomes. Doing surgery through smaller incisions and performing less radical surgeries are among these efforts.

People are seeking minimal-incision knee and hip replacement surgery, says Engh. Instead of the traditional 6- to 12-inch-long incision used in a standard total knee replacement, some surgeons are performing the surgery through a 4- to 5-inch incision. And instead of the typical 10- to 12-inch incision in a total hip replacement, surgeons are operating through one 4-inch cut or two 2-inch cuts.

"The [minimal-incision surgery] technique minimizes trauma to muscles, tissue and tendons and has less bleeding during surgery," says Garino. Patients have less pain after surgery, enabling them to walk with full weight sooner. The hospital stay is usually reduced as well.

"There are many advantages as long as we don't compromise our ability to put the implants in correctly," says Engh, adding that minimal-incision surgery is a more difficult operation to perform. "If you assemble a model ship on a desktop, it's easier to do, but if you try to assemble it within a bottle it is technically more difficult," he says. The technical difficulty also adds to the operating time. "The longer a patient is in surgery, the higher the risk of infection," says Engh.

Not all patients are candidates for minimal-incision surgery. People who are obese, have had previous hip or knee surgery, or those with unusual anatomy may be excluded, says Garino.

Minimally invasive surgery is another option for some patients. At Sinai Hospital, Mont performs a minimally invasive total knee replacement through an incision of 4 to 6 inches, bending the joint through the opening to expose different parts of it to work on. In a standard knee replacement, the entire joint is visible through a longer incision. Mont uses cutting procedures, leg positionings, and techniques that do not involve dislocating parts of the knee as in traditional replacement.

Even as researchers and surgeons continue to offer more options in prostheses and surgical procedures, Garino says the current technology is hard to beat. A hip or knee replacement is likely to last 20 years, he says. "The average patient takes a million steps a year. I challenge you to go home and find something in your house that you use a million times a year that has lasted for 20 years with no maintenance."

About the Author

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FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.