BackgroundHip and knee replacement are some of the most frequently performed surgical procedures in the world. Resurfacing of the hip and unicondylar knee replacement are increasingly being used. There is relatively little evidence on their performance. To study performance of joint replacement in England, we investigated revision rates in the first 3 y after hip or knee replacement according to prosthesis type.Methods and FindingsWe linked records of the National Joint Registry for England and Wales and the Hospital Episode Statistics for patients with a primary hip or knee replacement in the National Health Service in England between April 2003 and September 2006. Hospital Episode Statistics records of succeeding admissions were used to identify revisions for any reason. 76,576 patients with a primary hip replacement and 80,697 with a primary knee replacement were included (51% of all primary hip and knee replacements done in the English National Health Service). In hip patients, 3-y revision rates were 0.9% (95% confidence interval [CI] 0.8%–1.1%) with cemented, 2.0% (1.7%–2.3%) with cementless, 1.5% (1.1%–2.0% CI) with “hybrid” prostheses, and 2.6% (2.1%–3.1%) with hip resurfacing (p < 0.0001). Revision rates after hip resurfacing were increased especially in women. In knee patients, 3-y revision rates were 1.4% (1.2%–1.5% CI) with cemented, 1.5% (1.1%–2.1% CI) with cementless, and 2.8% (1.8%–4.5% CI) with unicondylar prostheses (p < 0.0001). Revision rates after knee replacement strongly decreased with age.InterpretationOverall, about one in 75 patients needed a revision of their prosthesis within 3 y. On the basis of our data, consideration should be given to using hip resurfacing only in male patients and unicondylar knee replacement only in elderly patients.

Recent events have made us question our ability to monitor the introduction and performance of a new prosthetic joint replacement. These concerns are mirrored in many other countries, even those with joint registries and other systems for detecting poorly performing implants. In the United Kingdom, as is the case in most European Union countries, we have assessment processes in place, particularly the CE (Conformité Européenne) mark, the National Joint Registry, and the Orthopaedic Data Evaluation Panel. It is important to realize that these organizations can only react to poor performance; it is not within their power as monitoring agencies to prevent a poor implant from entering the market. When an implant has been shown to perform badly, it is referred to the Medicines and Healthcare products Regulatory Agency (MHRA), which then discusses the report with the manufacturer. When it is deemed that there is unequivocal evidence of a serious problem with the implant, the MHRA issues alerts to all hospitals and practitioners. We have continuing concerns about how to assess and monitor modifications to already existing devices. Suggestions are made for improvements to this system, and the authors will welcome feedback.

Thermal plasma sprayed coatings are designed to improve both the biocompatibility and durability of implantable medical devices, and include pure titanium, cobalt/chrome alloy and hydroxyapatite.  Coated joint replacements have now been in continuous clinical use for thirty years and are applied to products manufactured or used in Europe, North America, South America, Africa, Asia and Australasia. Prostheses incorporating such coatings have been successfully implanted into several million of patients worldwide and to date there have been very few reports of any failure of an implant which could be attributed to problems with, or failure of, the coating. This paper summarises the early history of cementless prostheses and subsequent development, specification, validation, regulatory requirements and clinical performance of thermal plasma spray coatings provided by Accentus Medical.