National Joint Registries and Ankle Replacement - More of the Same?
Published date : 28 November 2012
Article date : 28 November 2012
By Craig Gerrand, Editor-in-Chief, Which Medical Device.
The inclusion of data about ankle replacement in the 2012 report of the National Joint Registry of England and Wales means the same focus on outcomes and outliers as we have seen in hip and knee arthroplasty directed at a new group of surgeons and implants. Data relating to ankle replacement have only been collected since April 2010, so data collection is in its infancy – for example compliance (an estimate of the proportion of patients entered in the Registry) is lower than for other joints (64% compared with over 93% for hip and knee replacement) and there are no survivorship data. Firm conclusions are therefore hard to come by. However, with the appropriate caveats, the results make interesting reading and most ankle surgeons will at least pause for thought.
In 2011, 492 ankle replacements were registered. 21 of these were revisions; 88% were for osteoarthritis (19% of which was post-traumatic) 9% were for rheumatoid arthritis and 75% were in the NHS. As expected this is a procedure of later life – the mean age of male patients was 68.6 years, and of females 67.2 years. The procedure itself is likely more technically demanding than other forms of arthroplasty – untoward intraoperative events occur in 5% of ankle replacements (fracture of the medial malleolus being the most common), compared with 1.5% of hip and less than 1% of knee arthroplasties.
The apparently high rate of intraoperative complcations could be a concern given the apparently low volumes of some surgeons and their units – the Registry suggests that most units performing ankle procedures do less than five in a year, with only two centres doing more than 25 a year. Experience from the Swedish Ankle Anthroplasty Registry suggests that the learning curve for ankle arthroplasty may be steep – with greater complications in low volume or inexperienced surgeons.
The Depuy Mobility Ankle Replacement and the Corin Zenith Total Ankle Replacement were the most commonly used devices (57% and 22% respectively). Indications for revision were aseptic tibial loosening, infection, osteolysis and malalignment in 24% of cases, polyethylene wear in 29% and undiagnosed pain in 29%.
The inclusion of ankle replacements in the NJR is to be welcomed. The focus on outcomes and outliers may be uncomfortable for some implant manufacturers and surgeons, but offers the real opportunity to improve the lot of our patients.
Comments:
Gregory C Berlet MD, Orthopedic Surgeon, Orthopedic Foot and Ankle Center, Columbus Ohio & Editor-in-Chief: Foot and Ankle Specialist, SAGE.
"My knowledge is tangential and based on following the trends on the Swedish Ankle Joint Registry where the data is quite interesting. When this Swedish data is analysed only one of the ankle replacement devices available in the US (STAR) is represented and its use has dramatically declined over the past few years."
Joint Registries are an easier task in a socialized system where participation is mandatory. In the US, currently joint registries are stilled perceived to confer either a competitive advantage or disadvantage depending on your perspective.
Our best hope for a joint registry in the US is for registration to be mandatory on all government pay contracts. This would pick up a significant amount of the ankle joint replacements done per year, although there would still be some outliers. This project would have great relevance in our medical community and I would expect a joint registry that includes total ankle to be proposed in the near future as part of the CMS quality initiatives."
Mr K Devalia, Orthopaedic Registrar and Mr Malik Siddique, Consultant Orthopaedic Surgeon and Which Medical Device Specialist Editor: Foot and Ankle.
“Current NJR data about total ankle arthroplasty are difficult to rely on because compliance is low – data about 36% of implants are not available. There are two centres in the UK carrying out more than 25 total ankle replacements per year. Like any other joint arthroplasty, there is a steep learning curve which for ankle replacement, is at least two years. Targeted training in ankle arthroplasty is therefore essential. The ankle joint is less forgiving to mal-alignment than other joints. Certain prosthetic designs such as the STAR (Scandinavian Total Ankle Replacement) do not tolerate mal-alignment as well as other designs (eg De Puy – Mobility) as the STAR is less congruent and has a flat top talus. Therefore the incidence of peri-prosthetic fracture, liner fracture and polyethylene wear is higher, leading to revision surgery. The current revision rate of 29% may be an underestimate because of low compliance. A high failure rate due to mal-alignment is not due to errors in prosthetic design but is mainly due to lack of training and surgical errors".
"There is therefore a strong argument that total ankle arthroplasty should be restricted to higher volume surgeons. Like hip and knee arthroplasty, ankle arthroplasty should be limited to those surgeons who are doing at least 20 ankle replacements per year. Foot and ankle surgeons who want to perform ankle arthroplasty should be encouraged to attend workshops to gain understanding and further experience. This will have a huge impact on the longevity of implants and results in the NJR.”
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