WHITE ROCK ORTHOPEDIC ASSOCIATION

EAST LAKE MEDICAL BUILDING

MARC S. GOLDMAN, M.D. 10611 GARLAND ROAD, SUITE 110 ROBERT A. GOLDBERG, M.D.

DALLAS, TX 75218

214.660.0505 Telephone www.whiterockorthopedic.com 214.660.4484 Facsimile

Minimally Invasive Total Knee Replacement

Description

Total knee arthroplasty (or replacement) is a surgery that is performed for severe degeneration of the knee joint. More than 300,000 people a year undergo the procedure. Minimally invasive total knee arthroplasty is a method of performing a knee replacement through a smaller incision.

Knees wear out for a variety of reasons, including inflammation from arthritis, injury or simply wear and tear. A knee replacement is the resurfacing of the worn out surfaces of the knee, replacing the cartilage that has been lost with metal and plastic. This is typically done through an incision down the center of the knee that averages 8" to 10" long. Minimally invasive total knee arthroplasty is a way of performing the surgery through a incision that is only 4" to 6" long, with potentially less damage to the tissue around the knee.

Risk Factors/Prevention

Although arthritis can run in families, most arthritis is due to a lifetime of wear and tear on the knees. The reasons that some people get severe arthritis and others don’t, or even why one of a person’s knees gets arthritis while the other does not aren’t known. Some known causes are previous injuries or obesity.

Symptoms

Knee arthritis leads to pain that is often associated with activity but can occur at rest. Patients often find it difficult to go up or down stairs, walk distances, get up from low seats. There can be associated swelling, stiffness or a feeling of instability.

Nonsurgical Treatment Options

The first step in treating knee arthritis is activity modification and a program of regular exercise and weight loss. The muscles around the knee protect it during activity and every step puts several times your body weight through your knee. Soft knee braces and modifications of your shoe can sometimes help.

Anti-inflammatories (NSAIDs) are usually the first medications recommended for arthritis. Some dietary supplements also might be helpful. The use of a cane or walker may also help to assist walking and improve mobility.

The next step is injections of either steroids (to decrease inflammation) or a lubricant (to improve the function of the knee). These can offer some relief and be repeated intermittently if helpful.

Surgical Treatment Options

Surgery is the final step in the treatment of knee arthritis. A knee replacement can help to eliminate most of the pain from arthritis and is indicated if the steps above have failed and the pain from the arthritis is limiting your lifestyle and activities.

Surgical options include knee arthroscopy (although this is rarely indicated just for arthritis), partial knee replacement and total knee replacement.

Total knee replacement can be performed in the traditional way, through an 8"- to 10"- incision or by using newer techniques, through a 4"- to 6"-incision. The goal of knee replacement is to provide a pain-free knee that allows relatively normal activities and lasts as long as possible. In order to achieve these goals it is extremely important that the knee replacement be inserted in the best possible position and with the bone and ligaments prepared very carefully to allow it to be functional and durable. Using the current techniques, 90 percent to 95 percent of knee replacements should last 15 years or longer.

The minimally invasive knee replacement technique attempts to accomplish all of this through a smaller incision. With the smaller incision come the potential benefits of a shorter hospital stay, a shorter recovery and a more cosmetic scar. There is no reason to believe that the knee will function any better. In fact, although there is no question that a knee can be put in through a smaller incision, it is still unknown whether it can be done as well.

One recent very early study of 70 minimally invasive total knees found that patients may have less blood loss, shorter hospital stays and better motion. Unfortunately, we won’t know if these new techniques affect the long-term function and durability of the knee replacement for 10 to 15 years. Long-term durability is much more important than whether you were in the hospital for 2 days or 4 days after surgery.

Research on the Horizon

To address concerns about accurate positioning of the knee replacement, advocates of minimally invasive knee replacement are working on combining the small incision with computer-guided instruments. The potential benefits, risks and costs of this have yet to be established.

2004