At a major medical conference held in Europe last spring, medical device manufacturer DePuy Orthopaedics, part of Johnson & Johnson's “Family of Companies,” announced “new and independent registry data” from the U.K.'s National Joint Registry (NJR) indicating that the “cumulative revision rate” was “significantly lower” for the ATTUNE Knee System compared to other knee replacements. However, a more recent analysis of data from an FDA database, published last month in the Journal of Knee Surgery, found that the DePuy product had an “unusually high” rate of failure.
That recent study, carried out by medical researchers from across the U.S., examined more than 230 reports from the Manufacturer and User Facility Device Experience (MAUDE) database. Reviewing clinical data from three different hospitals, the research team found 15 cases in which the implant-cement interface had come loose within two years of surgery – a failure rate of over 6.4 percent. This is much higher than the data DePuy announced in May, which examined approximately 10,600 patient records and found only 46 cases that required revision – a rate of 0.4 percent.
While there is no ready explanation for the discrepancy, it bears mentioning that the NJR report includes the following disclaimer:
“The National Joint Registry produces this report through its contractor, Northgate Public Services (UK) Limited (NPS) using data collected, collated and provided by third parties. As a result, neither NJR or NPS take any responsibility for any loss, damage, cost or expense incurred or arising by reason of any person using or relying on the data within this report, whether caused by reason of any error, omission or misrepresentation in the report of otherwise.”
Given DePuy's track record, that disclaimer could raise some serious questions. An important component of the ATTUNE Knee System was recalled in June of 2015 The Class 2 Device Recall involved a small wire spring that was part of a tool used in the operation, which had a tendency to fall off and into the surgical site. Meanwhile, the recently published U.S. study found that
“Patients presented with pain on weight bearing, effusion and decreased range of motion within 2 years after surgery. Radiographic evaluation demonstrated loosening of the tibial components in 2 of 15 knees...findings demonstrated gross loosening of the tibial component at the implant-cement interface.”
It appears that the number of complications related to tibial loosening has been underreported, which the researchers attribute to “failure of radiographs [x-rays] to assess the loosening.” They also point out that “MAUDE database reporting is not consistent.”
“When one looks at a case series, we really do not know the denominator, and this certainly could have been a series of cases out of more than 100,000 done, which would make this a rare event. Therefore, simply publishing cases are not evidence-based medicine, as we do not know how many of these were implanted.”
Meanwhile, the first lawsuit against DePuy citing failure of the ATTUNE Knee System has been filed in Alabama. The Johnson & Johnson subsidiary already has evidence against it going into litigation. In addition to the Class 2 recall of the surgical instrument in 2015, DePuy previously reported failures to the FDA yet continued to promote what it called a “novel design total knee arthroplasty system,” primarily to younger and more active patients (the average age of a patient undergoing knee replacement is 70). In 85% of cases, knee replacements last 20 years or more. In comparison, the ATTUNE Knee System is failing within 2-4 years.