Knee Replacement Overview – Patients | DePuy Synthes Companies

What can you expect from knee replacement surgery?

Deciding whether or not to get knee replacement surgery is difficult. Discussing your treatment options with your doctor is essential to helping you choose whether this is the right option for you. Learn more about knee replacement surgery to help formulate some questions to ask your doctor. Remember to write these questions down and bring them to your next appointment.

Each patient recovers differently. After surgery, you will work with a physical therapist to gradually increase your knee strength and mobility. Many people are able to go home soon after surgery. Others choose to recover at a rehabilitation center. This decision depends on the availability of family or friends to help you with daily activities; your home environment and safety considerations; and your overall evaluation after surgery. Your surgeon and you will decide together which course of treatment is best for you.

Typically, patients are able to drive again in about four to six weeks, so long as they can tolerate it and are not taking narcotic medications. If your job is not physically demanding, you may be able to return to work after about a month. These decisions are made in consultation with your doctor.

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Understanding knee anatomy

Learn how knee implants work

An image that shows how knee implants work like a normal knee joint. It also displays the various body parts that make up a normal knee compared to the components that make up a knee replacement joint.

One of the most effective ways to reduce severe knee pain and restore mobility is through knee replacement surgery. More than 660,000 knee replacements are performed each year in the United States to replace worn and arthritic knee joints. 1 Depending on your condition, your doctor may recommend either a partial or total knee replacement.

Types of knee implants: Partial knee replacement

The knee is made up of three areas: medial and lateral (the sides of your knee) and patella (the knee cap). When fewer than three of these areas need to be replaced, it is called a unicompartmental or partial knee replacement. By replacing only the damaged areas, you are able to retain more of your own natural knee.

Types of knee implants: Total knee replacement

Total knee replacement surgery resurfaces the bones at the top of the shin (tibia) and the bottom of the thigh (femur) with an implant made of metal and plastic parts.

The top of the shin bone is resurfaced with a metal tray topped with a medical-grade plastic spacer, called a bearing. This plastic replaces the cartilage, providing a cushioning surface for the new knee.

An area at the bottom of the thigh bone is resurfaced with a rounded metal part. This piece is designed to mimic the curve of the natural bone. The undersurface of the kneecap may also be replaced with a medical-grade plastic.

There are two types of bearings that may be used: fixed and rotating platform. In fixed-bearing implants, the bearing is firmly attached to the metal tray on the shin bone. It is "fixed" in position and cannot move. In rotating platform implants, the bearing can "rotate" or move as the knee bends, which allows for a more natural motion in the knee compared to traditional knee replacement. This rotation may also reduce the stress and wear on the implant. 2

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Learn more about DePuy Synthes Companies knee implants

Knee replacement surgery explained

The worn surfaces at the end of the thigh bone are removed using special instruments during knee replacement surgery, and the damaged joint is resurfaced with metal and plastic implants. At first, the surgeon shapes the bone to prepare for this new covering.

The top of the shin bone (tibia) is prepared in a similar way. The worn surface is removed and a new tibial base is placed on top of the remaining bone. This tibial base holds a hard plastic spacer that will become the new shock absorber between the smooth metal coverings. The doctor may also replace the back of the kneecap with a new plastic surface. These components can be fixed to the bone by either using bone cement or a "press fit," allowing the bone to grow into the coating on the implant. The doctor will typically decide which type of fixation to use based on numerous factors including age, activity level, bone quality and other associated medical conditions.

Near the end of the surgery, the doctor will secure the new knee. When the implant is in position and all of the supporting muscles and ligaments are working well, the doctor closes the incision with stitches or staples.

When your surgery is over, you will be taken to the recovery room. Generally, you can expect to be moved to your regular room within one to three hours after surgery.

The difference between partial and total knee replacement

The knee is divided into three areas: medial and lateral (the sides of your knee) and patella (the kneecap). In partial knee replacement, the damage to the bone is isolated primarily to one of these three areas. The surgeon replaces the damaged area of the knee only, allowing patients to keep more of their natural bone, tissue and ligaments when compared to a total knee replacement. And because it’s less invasive, they have the potential for a faster recovery than with a total knee replacement.

On the other hand, if the damage has affected two or more areas, a total knee replacement may be the answer.

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Learn more about knee replacement surgery

What to expect after knee replacement surgery

Knee replacement, in general, is a very successful operation. The success of your knee replacement is measured by whether or not you're satisfied with the decrease in your overall pain and the increase in your mobility, as well as the durability of your implant over time.

Once you have had knee replacement surgery, your surgeon will tell you when you can resume normal activities. Many patients are able to drive again in about four to six weeks, so long as you can tolerate it and are not taking narcotic medications. If your job is not physically demanding, you may be able to return to work after about a month.

Discover how to prepare yourself for surgery

References

Thomson Healthcare
McNulty DE, Swope SW, Auger DD, Smith T. The effect of crosslinking UHMWPE on in vitro wear rates of fixed and mobile bearing knees. ASTM STP 1445. Gsell, R. et al. American Society for Testing and Materials, West Conshohocken, PA. Available online at www.astm.org (2004).

NEXT: Treatment Options

DSUS/JRC/0914/0475(1) 10/2016

IMPORTANT SAFETY INFORMATION

The performance of knee replacements depends on age, weight, activity level and other factors. There are potential risks and recovery takes time. People with conditions limiting rehabilitation should not have this surgery. Only an orthopaedic surgeon can tell if knee replacement is right for you.

KNEE INJECTIONS

KNEE ARTHROSCOPY