13-Jun-06 10:00 AM CST

Surgical Procedure Repairs the Knee Rather than Replaces It

The Truth About Total Knee Replacements
Surgical Procedure Repairs the Knee Rather than Replaces It
By Albert D. Cuellar, MD

Often, when people hear of knee replacement surgery, they believe the entire knee is replaced. This is a common misconception. The surgery is actually considered a resurfacing procedure. That is, the diseased surfaces of the joint are shaved off and replaced with durable metals and plastic.

Because our knees are subjected to large forces everyday, the cartilage in the knee can wear out over time. When we walk, twice our body weight is put on the knee with every step. If we participate in sports, fall, or injure the knee, changes can occur in the smooth cartilage surface and may ultimately result in a painful arthritic knee. In some cases, people can develop strong inflammation in the joint that can destroy cartilage, causing arthritis.

A Joint Makeover

A total knee replacement resurfaces the bone. During the surgery, a few millimeters of the end of the femur (thighbone) are removed and replaced with a metal cap. In this operation, the anterior cruciate ligament (ACL) is removed, and sometimes the posterior cruciate ligament (PCL) is removed, depending on the type of prosthesis and the nature of the pathology.

A few millimeters of the upper end of the tibia (shinbone), along with meniscal cartilage, are removed. The top of the tibia is covered with a metal plate that holds a very durable plastic called polyethylene. The highly polished femoral implant rolls and glides over the plastic insert, mimicking the action of a normal knee joint. In approximately two-thirds of the cases, the undersurface of the kneecap is also removed, and a piece of plastic is used to reline the undersurface of the kneecap. The kneecap itself remains in place.

Pain Relief and Greater Mobility

In general, approximately 90% of patients with total knee replacements experience pain relief. After surgery, patients will still have most of their original ligaments, muscles, and tendons. By the time most patients come to realize they might need a total knee replacement, they have already had muscle atrophy or breakdown because of the inability to walk, stand, climb, or exercise. Patients might also have stiffness of the ligaments because of loss of motion or the loss of the ability to straighten or bend the knee.

Also, knee arthritis can cause limb deformities such as bowlegs and knock-knees. Knee replacement surgery typically corrects these deformities. Arthritis of the knees is often accompanied by irritation around the soft tissues. When the knee is resurfaced in a total knee replacement, you will still have these original structures, which will need to be rehabilitated.

The prosthesis will allow full extension and often flexion to 125 degrees. The range of motion a patient recovers depends a great deal on how well that person can tolerate and participate in the rehabilitation program in order to achieve extension and flexion. In general, knees that are replaced will last 15 to 20 years.

Heavier individuals tend to have more difficulty simply because there is more tissue around the knee, and they also tend to have more bleeding. If a patient with a severe arthritic knee waits a long time to have the procedure, there can sometimes be permanent joint deformities that will not allow full motion.

Total knee replacements are very cost effective. Various studies have shown that a knee replacement can save up to $50,000 or more in lifetime health care expenses because of less need for custodial and nursing home care.

Alternative Treatment Regimens

Total knee arthroplasty is the final stage in the treatment of knee arthritis. Initially, the treatment is weight loss and an exercise program to strengthen the muscles that support the knee. Acetaminophen can be used to relieve pain. Over-the-counter anti-inflammatory medications such as Motrin® or Aleve®, when indicated, can also be used. There are other prescription medications that are helpful as well. Cortisone can be injected in the joint to help with pain and inflammation. There are also other types of medications that can be injected into the knee to try and ease the pain, discomfort, and stiffness of arthritis.

Ultimately, patients with severe, persistent pain in their knees who have not had significant relief with other measures may consider knee replacement.

Sidebar 1:
Conditions Requiring a TKA

The following symptoms may indicate a need for TKA:

• Severe knee pain that limits everyday activities, including walking, going up and down stairs, and getting in and out of chairs

• Moderate or severe knee pain while resting, either day or night

• Chronic knee inflammation and swelling that doesn't improve with rest or medications

• Knee deformity — a bowing in or out of the knee or stiffness —- and the inability to bend and straighten the knee

• Failure to obtain pain relief from nonsteroidal, anti-inflammatory drugs

Sidebar 2:
Patient Home Preparation

There are several actions you can take before knee replacement surgery to facilitate your recovery, including preparing your home. Making your home as comfortable— and as safe — as possible can ease much of the discomfort and prevent many of the hazards that come with surgery recovery. Here are some home-preparation ideas to make your home easier to navigate after surgery.

• Prepare a temporary living space on the main floor to avoid using stairs during your early recovery.

• Install secure handrails along stairways for long-term recovery.

• Install secure handrails as well as a stable bench or chair in showers or baths.

• Obtain a stable chair with a firm seat cushion and back, two armrests, and a footstool for periodic leg elevation.

• Remove all loose carpets, cords, and other obstacles that could cause you to fall.

• If you have pets, arrange for a family member or friend to “pet sit” or board your pets at a local veterinary office or pet store.

• Arrange furniture to allow mobility with a walker.

• Make sure hard-to-reach objects, as well as regularly used items such as a phone and medications, are easily accessible.

• Prepare and freeze meals before surgery or arrange for someone to help you at mealtimes.

• Make plans for someone to run your errands and drive you to appointments. Alternatively, you can arrange for a short stay at an extended-care facility during recovery to ensure you have help at hand and prevent changing your home atmosphere.

For additional information on this article, please contact:

Albert Cuellar, M.D.

Source: KSF Orthoapedic Center, P.A.

http://www.ksfortho.com