What is Knee Arthroplasty?

Arthroplasty literally means a surgical repair of a joint. It is a procedure performed by an orthopedic surgeon who replaces or repairs a dysfunctional joint. In this case, it is the weight-bearing surfaces of the knee joint.

Knee arthroplasty can be performed as a total or a partial knee arthroplasty.

Often knee joints have been damaged through either injury or the long term degeneration of an arthritic condition.

Arthritis is really a generic term that describes over 100 different medical conditions that affect the musculoskeletal system. In some severe cases, where the joints have been disabled and the individual is no longer able to be functional, arthroplasty surgery is recommended.

Causes of knee pain include osteoarthritis, meniscus tears, cartilage defects, ligament tears, rheumatoid arthritis and psoriatic arthritis.

Currently there are forms of arthroplasty which include re-sectioning the joint structure, resurfacing the joint structure and replacing the joint structure.

For the last 45 years the most common form has been a surgical replacement with a prosthetic. The most common form of arthroplasty is replacement of the hip, knee and hands.

Other conditions where arthroplasty is done include a vascular necrosis, congenital dyslocation, traumatized joints and rheumatoid arthritis.

Knee Pain Relief

The purpose of any arthroplasty surgery is to relieve the pain and restore range of motion to the individual. Many times this means improved ability to walk, improve muscle strength or improved ability to use their hands.

While a total knee arthroplasty has been practiced for decades it is only been in the last 10 years that researchers have made technological improvements in the joint replacements in order to both increase the lifespan of the prosthetic and decrease the risk to the individual following the surgery.

For instance, significant advances have occurred in a total knee arthroplasty as to the type and quality of the materials used.

Most recently, manufacturers have begun using ceramics which leads to improved longevity of the joints. The primary indication for a total knee arthroplasty is to relieve pain and improve functionality.

Correction of a significant deformity may be an indication, but is rarely the primary reason for surgery. Prior to considering any arthroplasty surgery orthopedic surgeons must exhaust all conservative treatment measures.

More recently, resurfacing arthroplastic surgical procedures have been developed which are a temporary fix for an individual who has significant degenerative joint disease. This procedure has been used in order to increase the length of time an individual may be functional.

For instance, the average lifespan of a total hip replacement is 20 years for the prosthetic joints.

Unicompartmental Knee Arthroplasty

Unicompartmental knee arthroplasty, also referred to as a partial knee replacement, is a surgical procedure used to relieve arthritis in one of the knee compartments in which the damaged parts of the knee are replaced.

There is actually nothing “partial” about this replacement. It is a total replacement of the part of the knee that is arthritic.

Your knee is divided into three “compartments”- medial (the inside part of the knee), lateral (the outside), and patellofemoral (the joint between the kneecap and the thighbone).

Most patients with arthritis severe enough to consider knee replacement have significant wear in two or more of the above compartments and are best treated with total knee replacement. Around 10 to 30 percent of patients have wear limited primarily to one compartment, usually the medial, and may be candidates for unicompartmental knee arthroplasty.

In a unicompartmental knee arthroplasty, the surgeon uses an incision of just 3-4 inches, whereas total knee replacement typically requires an incision of 8-12 inches, as well as having a longer recovery time.

Arthroplastic Surgery Operation

An arthroplastic surgery is done under general anesthesia and may last up to several hours.

During this procedure the joint is fully exposed and all of the damage bone and cartilage are either removed or reshaped. Patients can expect several days in the hospital following the procedure as well as medications to use pain and extensive physical therapy.

Physical and occupational therapy are used to bring the knee back to near normal function and avoid complications.

Currently, arthroplasty is usually employed only as a last resort. In order to extend the functionality and abilities of the individual past the point of the demise of the prosthetic, orthopedic surgeons must weigh the risks versus benefits of implanting total joint replacements in an individual who is younger than expected.

Knee arthroplasty accounted for 4.6% of all United States operating room procedures in 2011, and the demand for primary total knee arthroplasty is projected to increase to 3.4 million surgeries performed annually in the U.S by 2030.

As with any surgical procedure there can be complications. In knee arthroplasty surgery complications can be, but are not limited to, bleeding, infection, blood clots in the legs or lungs and loosening of the prosthetic heart once it is then implanted.

During surgery it is possible to injure nerves are blood vessels which results in weakness or numbness. Other risks will depend upon your specific medical conditions as well as those general risks that accompany anesthesia.

For More Information:

Joint Replacement Institute: Knee Revision Surgery

TriRivers Surgical Associates :Understanding Joint Resurfacing

Radiographics: Joint Arthroplasties and Prostheses

Price AJ, Waite JC, Svard U (June 2005).
Long-term clinical results of the medial Oxford unicompartmental knee arthroplasty“.
Clin. Orthop. Relat. Res.; (435): 171–80. doi:10.1097/00003086-200506000-00024

Acta Orthopaedica: C-Reactive Protein Levels After 4 types of Arthroplasty

Fast Track Your Recovery From A Total Knee Replacement:: How to Eliminate Pain And Pain Medicine The Quickest Way Possible

Top Photo: Phalin Ooi / Flickr

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