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SAIPH® Knee Awarded ODEP 5A

As stated by Mike Tuke at The Forever Active Forum recently held in Melbourne, we are pleased to confirm that the ODEP panel has updated the ratings for SAIPH® and this now includes a 5A Rating1.

How ODEP ratings are awarded and what this means for SAIPH®

ODEP ratings are awarded following assessment of: A. implant performance (risk of revision), and B. the number of patients for which data is available.

  1. A. An ODEP rating is awarded for a given number of years if the available data shows a revision rate lower than the benchmark value. The purpose of this is to ensure a device has an ‘acceptable’ rate of revision. For example, to achieve an A* rating at 5 years, a device needs to demonstrate a revision rate of lower than 4%, including the upper confidence limit.

The latest NJR summary report for the SAIPH® Knee shows that it has a 5-year revision rate of only 1.6% (95% CI: 0.7%-3.9%)2 – which is lower than the average of all TKR in the NJR (2.2%) and amongst the lowest of all available devices!

  1. B. The number of patients for which data is available is important given that the statistical probability of failure becomes meaningful when it is calculated from the ‘real evidence’ of a substantial dataset. ODEP factor this into ratings in two ways. Firstly, the benchmark requires a minimum cohort size for that time period. Secondly, the benchmark revision rate requires that the upper confidence limit is also below the defined revision rate. A device’s revision rate may have a high upper confidence limit due to the timing of failures, because the total cohort is small across all years or because the revision rate is close to the benchmark value.

The ODEP rating is just one of a number of data ‘credentials’ we explore in our series for the SAIPH® Knee and is based on UK data. Within the MatOrtho® philosophy for safe introduction of new technology, the device has been released under a limited availability and with a closely monitored safe introduction strategy. In the 9 years since first use, there have been around 4,500 procedures worldwide to date and, of these, 844 have been performed in the UK and recorded by the NJR2.

Note that, not only is the upper confidence limit of the SAIPH® revision rate (3.9%2) below the level set for a 5A rating (the 5A limit is 6.0%), it is also lower that that required for a 5A*. However, due to its limited availability, ODEP ratings will track behind the number of years simply due to numbers implanted in the UK: the number of patients that received their SAIPH® Knee 5 or more years ago remains small – so the cohort size results in the current ODEP rating for the SAIPH® Knee – 5A.

Different ratings for SAIPH® Knee ‘constructs’

To protect patients from being prescribed versions of implant brands that do not alone achieve the rating for that ‘brand’, ODEP have separated devices into constructs. For the SAIPH® Knee, this means separating data for its use without patella, with the cementless patella and with a cemented patella. Whether or not using a patella affects outcomes is an ongoing debate (look out for our upcoming report on the conceptually identical MRK™), nevertheless, separating the SAIPH® Knee into constructs has an impact on available cohorts.

Following the same rationale as described above, each construct is assessed against the revision rate and number of patients at a given benchmark time point:

  1. SAIPH® is most commonly used in the UK without a patella resurfacing and there is sufficient data available for ODEP to award the base construct a 5A rating: the revision rate, including confidence interval is low, 1.7% at 5 years (95% CI: 0.7%-4.0%), and the number of patients exceed that required for a 5A rating.
  2. When used with a patella SAIPH® has an excellent revision rate of 0.5% at 5 years (95% CI: 0.1%-2.0%).

The cementless patella (which is the same design as the 10A*-rated MRK™) has no revisions at 5 years – which is exceptional – however the cohort size at 5 years meets ODEP requirement for a 5B rating.

The cemented patella was introduced after the SAIPH® was first used. It is reported in the UK with a revision rate of 2.8% (95% CI: 1.1%-6.3%), based on a smaller cohort and with few patients receiving it more than 3 years ago. Therefore, with a small cohort size (and wide confidence interval) this construct meets the ODEP criteria for a 3A rating.

Conclusions

The ODEP ratings system was devised to independently review the performance of devices based on available data for defined postoperative durations. The SAIPH® Knee is being made available to the world in a staged process in which data is constantly reviewed and seen to meet performance expectations. Due to this program, available data is growing over time.

The SAIPH® is demonstrating exceptional performance with a consistent low revision rate and, as the number of patients who receive it grows, we are seeing regular advances in measures such as the ODEP ratings.

To see the new criteria introduced in 2018 go to: http://www.odep.org.uk/Portals/0/Forms/Criteria/ODEP_Criteria_Knees.pdf.

  1. For latest ODEP ratings go to www.odep.org.uk
  2. Northgate Public Services (UK) Limited. NJR Summary Report for the SAIPH® Knee. May 2018. Ref: Summary.Report.KP_Femoral_Saiph.17/05/2018.06:04

 

 

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