Rheumatoid arthritis (RA) is an autoimmune disease. Autoimmune means that the immune system sees normal body tissue as “foreign” and attacks it. In the case of RA the synovial tissue around the joint is affected the most. Inflammation of the synovium is called synovitis. RA can cause joint damage in more than one joint.
Patients with RA may need a joint replacement. But how long will the new joint last if the synovitis comes back? Researchers in Japan studied 128 patients with RA who got a total knee replacement (TKR). A specific kind of implant called the Kinematic prosthesis was used in each patient.
Thirteen to 19 years later, the authors found a total of 36 knees to include in the study. Some patients had died or couldn’t be found. Others had serious health problems that kept them from being examined.
Doctors measured pain levels, range of motion, and walking ability before and after the TKR. They also checked on the number of infections, fractures, and other problems after surgery. Some patients needed a second operation on the joint replacement. This is called a revision operation. Six patients had a total hip replacement and two others had an ankle replaced.
The results of this study showed survival rates of the Kinematic prosthesis in patients with RA was close to 94 percent after 15 years. The authors say this is satisfactory. The Kinematic implant compares equally, if not better, to other types of implants used in previous studies.