The topic of knee joint replacement is packed with so much information, that one article alone would not cover it adequately, so I’m going to touch on the most important aspects of this surgical procedure, whose number of patient-recipients is increasing rapidly.

First, knee joint replacement is not a surgery in which your knee joint is “chopped out” and a new one inserted – at least not the traditional “primary replacement” procedure. Rather, the arthritic joint surfaces of the femur bone (thigh), tibia (shin) and patella (knee cap) are carefully and specifically removed with special “cutting” jigs” or guides.

This precise trimming and shaving of the three bone surfaces prepares them to accept the final implants, which are shaped to literally fit like a glove onto the prepared surfaces.

Joint replacement in age groups in the 50s and even younger is becoming more common.

Individuals are declared candidates for knee replacement surgery if their arthritis is severe enough that it becomes almost impossible to live his or her life on a daily basis, the risk of falling has increased to an unacceptable level and the pain from the arthritis has become more than traditional non-surgical treatments can manage.

The type of knee joint replacement procedure being discussed here is the total knee replacement. There are different varieties of partial replacements, but we will discuss those in upcoming articles.

Total knee replacements consist of four major implants that comprise the whole package: the femoral implant, which covers the end of the thighbone; the tibial implant, which sits atop the prepared surface of the shin bone and the patellar implant, which is a plastic dome-shaped component and becomes the new undersurface of the kneecap.

The components are made of a variety of specialized metal and a space-age, high-density plastic that resists wear. One metallic implant covers the thigh and the other, the shin bone area, while one of the plastic implants covers the underside of the kneecap and the other is placed between the two metallic implants, serving as a “spacer” of sorts. The individual implants come in various sizes and shapes to accommodate individual variations of the knee joint for a more “custom” fit.

The surgery is typically performed under either a general anesthetic (where the patient is asleep) or a combination spinal anesthetic (saddle block) light general anesthesia and more recently and frequently, with the addition of a special nerve block called femoral nerve block, which helps significantly reduce pain after surgery.

Blood loss is typically minimal during surgery, thanks to the use of a device called a pneumatic tourniquet, which is inflated much like a blood pressure cuff effectively stopping circulation to the lower extremity during surgery, and drain tubes are often placed inside the knee for 24 to 48 hours to prevent unwanted blood collection inside the joint. Surgical time can range from less than an hour to two and a half hours, depending on various factors including surgeon speed, level of deformity of the knee and patient size.

There was a time when joint replacement surgery was dedicated almost exclusively to patients over the age of 65, mainly because they would not outlive their implants, which would necessitate a revision procedure, which I will discuss in upcoming articles as well.

This is no longer the case. With improved implant manufacturing, state-of-the art surgical techniques and a population of younger and younger patients with end-stage arthritis, joint replacement in age groups in the 50s and even younger is becoming more common.

Because joint replacement components have a somewhat limited lifespan (10, 15 and 20-plus years), the potential for a revision surgery increases as the age of the recipient decreases.

One disturbing trend I have personally seen is the number of morbidly obese patients receiving knee joint replacements, even at younger ages. This is an alarming trend for a couple of reasons; first, the dramatically increased weight loads being placed on the implants will have a direct impact on their longevity and second, patients with a BMI (body mass index) greater than 40 are at a considerably higher risks for medical complications such as blood clots, stroke and infection.

At some point, weight loss before or after these procedures will have to be taken seriously and perhaps new combination programs dealing with weight and its correlation to arthritis and joint replacement will be developed. You may have seen how joint implant companies have been increasing their marketing to individual prospective patients. These companies all have something about their parts that is a bit different, unique and allegedly better, than the competition. Your surgeon will be best able to determine which implant is best suited for you, although knowing something about these implants will never hurt you and you should be a “partner” in the decision-making process anyway.

Knee joint replacement surgery can be a real godsend for people who suffer from terminal arthritis, but like many other things, just getting a knee replacement alone won’t solve all the problems. Things like weight (really, a very important factor) and genetics can and will come into play in many cases.

For more information on knee joint replacement, visit www.bone-and-joint-pain.com and visit www.healthcare-advocates.org to learn more about how they can help you if/when you are told you need a “new” knee or other joint.

Chisholm’s expertise in nursing, orthopedics and surgery spans more than 30 years. For more information on orthopedic-related topics, visit www.bone-and-joint-pain.com. Submit questions or comments to Ken at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

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