Mobile bearing vs fixed bearing prostheses for total knee arthroplasty for post-operative functional status in patients with osteoarthritis and rheumatoid arthritis

Jacobs W, Anderson PG, van Limbeek J, Wymenga AAB

Bookmark this:

more ...

Email this page

Summary

Which type of knee implant is better in Total Knee Replacement surgery for osteoarthritis and rheumatoid arthritis of the knee: mobile or fixed bearing?

To answer this question, scientists analysed 2 studies that tested over 150 people with osteoarthritis of the knee (6 had rheumatoid arthritis). These people had total knee replacement surgery with either a mobile or fixed bearing knee implant and were studied 1 or 7 years after the surgery. These studies provide the best evidence we have today.

What is osteoarthritis and rheumatoid arthritis of the knee and what types of knee implants are there?

Osteoarthritis and rheumatoid arthritis are two forms of arthritis that can affect the knees. In some people, damage and pain in the knee from arthritis may be severe enough for surgery. In these people, the whole knee joint can be replaced by an artificial joint or knee implant. In total knee replacement surgery the ends of the long bones of the leg are usually replaced with metal ends and an insert is placed in between them. The insert can either be "fixed" into place on the end of one bone or not as fixed which makes the insert more movable or "mobile". It is thought that people with a mobile bearing may be able to move their knee more and function better than people with a fixed bearing.

What did the studies show?

The two studies show that the range of motion/movement of the knee was about the same in people who had a fixed or mobile bearing knee implant. The year long study shows that slightly more people with a mobile bearing knee implant had less pain and better function than with a fixed bearing knee implant. But the seven year long study showed no differences in pain or function between the mobile or fixed bearing knee implants.

What is the bottom line?

The level of quality of the 2 studies in this review is "silver". It appears that mobile bearing knee implants provide the same amount of range of motion/movement and pain relief as fixed bearing implants in total knee replacement for osteoarthritis and rheumatoid arthritis of the knee. Ability to function with either type of implant is also the same.

This is a Cochrane review abstract and plain language summary, prepared and maintained by The Cochrane Collaboration, currently published in The Cochrane Database of Systematic Reviews 2009 Issue 4, Copyright © 2009 The Cochrane Collaboration. Published by John Wiley and Sons, Ltd.. The full text of the review is available in The Cochrane Library (ISSN 1464-780X).
This record should be cited as: Jacobs W, Anderson PG, van Limbeek J, Wymenga AAB. Mobile bearing vs fixed bearing prostheses for total knee arthroplasty for post-operative functional status in patients with osteoarthritis and rheumatoid arthritis. Cochrane Database of Systematic Reviews 2001, Issue 2. Art. No.: CD003130. DOI: 10.1002/14651858.CD003130.pub2.

This version first published online: April 19. 2004

Abstract

Background

The polyethylene insert in a total knee replacement (TKR) can be fixed to the tibial plateau or it can have freedom of rotation and / or translation. It is not yet clear whether there are differences in functional or clinical results between the two prosthesis types.

Objectives

The goal of this review is to assess if a mobile bearing total knee prosthesis provides a better range of motion (ROM) and a better functional outcome than a fixed bearing prosthesis in patients with rheumatoid arthritis or osteoarthritis after total knee arthroplasty.

Search strategy

We searched the Cochrane Library (issue 2002-3), Current contents (1996 to September 2002), and MEDLINE (1966 to September 2002). Reference lists of selected articles were also included.

Selection criteria

Randomised controlled trials or controlled clinical trials were selected which used a functional or clinical outcome measure comparing mobile (rotating and/or sliding) with fixed bearing types.

Data collection and analysis

Data was collected on relevant demographic data and functional outcome measures like Range of Motion, specific measures of activities with daily tasks, and composite knee scores such as Knee Society Score, Hospital for Special Surgery score and similar scores. Only controlled studies comparing a fixed bearing with a mobile bearing type of TKP were considered.

Main results

Two randomised studies were encountered evaluating the difference in functional or clinical outcome of the two prosthesis types. The methodological quality of the studies was low. The study with the best quality found no difference in ROM, but found a superiority of the mobile bearing on Knee Society Score and Oxford Knee Score and the pain sub scores of these clinical measures. The second study found no differences.

Authors' conclusions

We could find no evidence of superiority for one of the two prosthesis types with regard to ROM or functional performance of the patients. The majority (96%) of patients in the 2 included studies had OA. Therefore, the results reflect primarily results in OA patients.

top of page | contact us | about this site | disclaimer | privacy