By Martin Pickford
During the last thirty years there have many new technologies in joint replacement which were introduced with the aim of improving patient outcomes. Many of these such as carbon reinforced polyethylene, large head metal on metal hips and the use of low modulus materials in the manufacture of hip stems, did not have the desired effect and disappeared within a few years. However other technologies such as hydroxyapatite, ceramic heads and crosslinked polyethylene have proved to be very beneficial and today, literally millions of patients are continuing to benefit from their introduction.
After the well publicised failure of the Capital hip in the late nineties, a review of total hip replacement was undertaken by the National Institute of Healthcare and Clinical Excellence (NICE). Their subsequent guidelines suggested that only products with considerable clinical history should be considered for use, in the interest of patient safety. More precisely they recommended that only products with single digit failure rates at ten years should be considered for use. Realising that such a directive was anti innovation, the guidelines were subsequently broadened to include products that had less than ten years follow up but which nevertheless were exhibiting outcomes in line with what could be reasonably expected at ten years.
The two paragraphs above sum up the quandary faced by the medical device industry, users of medical devices, and regulators alike. That is, how to ensure patient safety and at the same time allow the usage of new technologies which may improve long term outcomes. The Orthopaedic Data Evaluation Panel (ODEP) was given the job of evaluating clinical outcomes data, submitted by manufacturers for their devices. Submissions would be rated based upon length of follow up, number of patients and quality and completeness of data. The panel would then, if satisfied, award a rating to the product which consists of a number (3, 5, 7, or 10), based upon the number of years followed up, followed by a letter (A,B or C) denoting the perceived quality of the data. It is also required that for any product with less than ten year follow up, further datasets must be submitted as longer time intervals are reached. Failure to do this can lead to a product being declassified.
ODEP have now been reviewing submissions for over ten years and such data can come in many forms
1) Peer reviewed published papers from multicentre, large cohort studies
2) Registry data
3) Data from company post marketing surveillance studies
4) Peer reviewed published papers from single centre studies (often surgeon developer centres)
The quality of submissions is variable with only about half of them being accepted at first viewing: Lack of completeness or obvious data errors being the primary causes of rejection. Suffice to say that for a submission to receive an A rating the following criteria need to be met.
a) Revision rate within the NICE guidelines
b) Large cohort from more than one centre.
c) All patient deaths and patients lost to follow up noted and recorded
d) All revisions quantified along with reason for failure of original implant.
In the ten years since the launch of ODEP ratings, the system has gained broad acceptance in the UK and overseas. In 2012 over ninety percent of hips implanted in primary procedures recorded in the National Joint Registry of England Wales and Northern Ireland (NJR), had an up to date ODEP rating. Many of them however utilised products which have been on the market for less than ten years. It is felt that this shows that ODEP has managed to create a good balance between patient safety and new innovations. However that is not the end of the story. The data is showing that many products are now performing better than the original NICE guidelines required. This shows that new technologies are leading to improvements in clinical outcome as hoped. As a result there is a tightening of NICE guidelines currently under consideration which will lead to further refinements to the ODEP rating system.
In summary the introduction of the ODEP system ten years ago does appear to have led to an improvement in clinical outcomes, as judged by the NJR, and that this improvement has not been at the expense of innovative technologies or new products.