One of the most life-changing forms of surgery is joint replacement or arthroplasty. Joints may require replacement because of injury, osteoarthritis, rheumatoid arthritis or other bone disease. A person in receipt of a joint replacement, in addition to feeling a relief from pain, gains mobility with a consequential boost to their health. In the United States alone, over 150,000 patients benefit from these types of operations annually.
The joints able to be replaced by artificial materials include hip, knee, shoulder, ankle, elbow and finger joints. Hip joint and knee joint arthroplasties are the most commonly performed of these replacement surgeries.
Materials used as joint replacements, or prosthetics, require being inert, strong, and hard wearing. Any metals used as must resist corrosion by bodily fluids. Metals suitable for the production of replacement joints include stainless steel or alloys of cobalt, chrome, and titanium.
Some joints use both parts made of metal. Occasionally, such a metal joint may incorporate a plastic spacer between the two metal parts. Joints incorporating such a plastic spacer tend to wear out a quicker rate than metal-only joints.
In a recent development, the metal part of the new joint fits into an artificial socket made of the hard-wearing highly cross-linked polyethylene. This forms a very hard-wearing joint that may be a better option for young active patient or for heavily built people.
An alternative material used in artificial joint production is a form of ceramic. Ceramic joints are a fairly recent advance in the field of arthroplasty. They appear to be very hard wearing and scratch resistant. Owing to their recent introduction, the long-term use of such implants has not yet been evaluated..
The artificial implants are frequently held within the patient’s bones using a specialized bone cement. Implants held by such cement sometimes loosen, necessitating a second joint replacement surgery. The recent development of cement-less joints in which the implant is joined directly to the bone may prevent the need of second implant surgeries caused by such loosening.
An orthopedic surgeon will choose the most suitable prosthetic materials for a joint replacement. Such a decision depends on the type of joint being replaced, the age of the recipient, and how active a lifestyle they live.
Whenever a joint has been replaced, follow-up physiotherapy is essential to ensure optimum joint mobility.
References:
The Arthritis and Glucosamine Reference Center
Joint Replacement.com
Hip Replacement Implant Options by Jonathan Cluett, MD.
Arthritis Foundation
