Orthopedic Knee Surgery

KNEE REPLACEMENT SURGERY IMPLANT FIXATION METHODS

There are four ligaments that will ensure the knee joint works correctly. Their job is to assist hold the bones in place. When the knee is sound then they are very effective. However, when a knee joint deteriorates, say due to joint disease, damage and scarring can develop to these ligaments. The objective of knee replacement surgery is to replace some or all of these ligaments and also the surfaces of the knee joint by synthetic components or prostheses. These prostheses need help to stay in place and two types of implant fixation techniques can be used – cemented or cementless.  With both methods knee rehabilitation exercises to help speed up recovery are important.

CEMENTLESS FIXATION METHOD

Cementless fixation was first unveiled in the 1980’s and entails making use of implants whose surfaces are attractive to new bone growth so that they would attach to the bone without using any kind of cement or adhesive. In other words the new bone grows into the specially coated surface of the implant. Cementless implants do require using screws to aid the stability of the implant until the new bone grows sufficiently to provide adequate support. Because it is essential to wait for the new bone to grow into the implant and because of the use of the supporting screws, recovery time is more lengthy than if using a cemented fixation technique. Even though this procedure has proved as effective as cemented fixation in many cases, it has not solved the problems a result of bone reduction and wear in the implant (see below).

CEMENTED FIXATION METHOD

The most common method these days is cemented fixation in which a polymethylmethacrylate cement, a special fast curing bone cement, is used to hold them in place. Knee replacements performed using this method have had excellent outcomes with an expected life of 15 to 20 years. In the other method, cementless fixation, the actual bone is encouraged to actually grow into the surface of the implant.  Bone reduction and wear of the implant is also an issue with this method.  Nonetheless, despite these issues, which are rare but not unknown, cemented fixation has turned out to be to be a most reliable technique in total knee replacement in most cases including in young patients who have an energetic lifestyle and where joint disease was relatively advanced.

ISSUES

How long a knee replacement lasts and how well it functions are determined by the overall health and weight of the recipient as well as the amount of use the knee joint gets and the stresses placed on it by this use. Weight management is very important in reducing wear and in lessening the risk of other conditions.

When orthopedic knee replacement surgery is carried out, the harder bone at the top of the tibia or shinbone is removed. The softer more porous bone that is left must absorb the stresses that your knee joint is put under, which under normal use can be considerable. If these stresses are greater than this bone is capable of absorbing then the metal alloy components of the prosthesis can loosen. Over a period of time, these kinds of excessive loads may well cause the prosthesis to sink into the softer bone tissue or loosen its adhesion to the bone.

Loosening of the prosthesis and sometimes bone reduction can be a result of the polyethylene layer between the metal components wearing unevenly. This may be caused by an uneven gait where by the knee is subjected to uneven loads leading one side of the knee implant to push into the bone whilst the other side lifts off from the bone. This uneven wear may also cause tiny particles of the polyethylene layer to rub off. This “debris” may cause the body to set off a biological reaction that could cause further movement of the knee implant. Bone loss may also be a direct result this. What happens then is that the surrounding cells absorb these minute particles. The body’s immune system senses this and attempts to eliminate them by triggering an inflammatory response. This response may also cause osteolysis, a condition where the cells essentially take away some of the bone from around the prosthesis. As wear increases so does the bone loss and the weakened bone causes the implant to loosen more.

CONCLUSION

It seems that both methods are successful in total knee replacement surgery. Having said that, the use of cementless implants has only been relatively recent and so long term comparisons of the two methods are unavailable but in the short term, it would seem that the success rates are comparable.

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Knee surgery recovery depends on many things. Obesity can affect your knee rehabilitation as shown in this article.

The solution to people with knee problems can be a mix of medication and proper diet. For more serious cases, knee surgery may become inevitable. This means that the entire knee will have to be replaced with an artificial joint so that they can walk again without pain. Unfortunately, it may be more difficult for people who are considered to be obese to enjoy the long-term effects of surgery. There are even experts that say obesity and knee replacement do not particularly mix well.

Why Knee Replacement Is Important

The joints that make up our knees are cushioned and protected by a material called cartilage. It is the same organic material our ears are made of. Factors such as too much fast food and sports like running or basketball can contribute to the reduction of cartilage in the knee. The problem results to the joints not moving properly and excruciating pain.

Obesity can even play a part in the degradation of the knee. As mentioned above, certain foods that cause obesity in general can also affect the cartilage. Furthermore, the knee of an obese person is under more weight and pressure compared to a healthier individual, increasing the possibilities of osteoarthritis.

How Can Obesity Affect Knee Replacement?

Arthroplasty or knee replacement is considered a major surgery. Hence, there are several tests that patients are required to take to make sure that they fit to be on the operation table. These tests include a blood-clotting test and electrocardiogram or ECG, among others. These tests may reveal other conditions that may affect the success of the operation .

This is where obese patients usually have a problem. Due to their weight condition, it is more likely that they also have high blood pressure and heart ailments. This means doctors will have to take extra precaution during the actual surgery. It is even possible that surgery will not be an option once obese patients have been found to have other medical problems.

Issues after the Knee Surgery

Even if the surgery becomes successful, obesity can still become a major hurdle during the recovery period. The existing conditions of the patient may delay the complete healing of the wounds and how the artificial knee adapts to the leg. Most importantly, physical rehabilitation may be longer for people who are weight challenged.

It will actually take more time for them to get back the strength of the muscles and bones. Because of their weight, they are mostly likely to be given continuous passive motion or CPM treatments, so they and their artificial knees can start physical exercises without so much strain.

Aside from the long recovery, certain studies have shown that 1 out of 10 obese people who had arthroplasty found that the surgery was not successful after five or six years. This is because the additional weight caused more stress on the artificial joint. This caused the joints to develop stiffness or malfunction altogether. This is a stark contrast to the 100 percent success rates of knee surgery on people who are not obese.

A strict doctor ordered rehabilitation always follows knee replacement surgery. Unfortunately, this rehab is only enough to give you some mobility and get back part of your life. They don’t expect people with knee replacements to have the full abilities like they once did, so they don’t even try. With the right exercise and routines, though, you can have that life back, despite what the doctors tell you. Take the time to learn about rehabilitation from knee replacement surgery, and how you can ease your fear of living a sedentary life by taking action.

Article Source: http://EzineArticles.com/?expert=Jerry_Seaman

How can obesity impact a persons health?

However, this is one of the very minor problems of obesity. Excessive weight bearing on the knee and ankle joints is a major cause of the wear and tear that occurs in joints.

Weight Loss Forum-Obesity

I developed horrible arthritic pain in my joints, and due to the medication I was taking and my metabolism basically crashing to hell, I gained nearly 100 lbs back.

How will Obesity Affect You and What Can You Do?

Extra weight will take a toll on your joints. Obesity has also been linked to gout, which is when uric acid that cannot be excreted collects in the joints of the toes. 

Technorati Tags: knee replacement surgery, knee surgery, Knee Surgery Recovery, obesity