The National Joint Registry 22 years on: what have we learned about knee replacements?

The National Joint Registry (NJR) of England and Wales was established in 2002 to collect, analyse and report high-quality data about joint replacement surgery. Submission of knee arthroplasty data has been mandated since 2003 in the private sector, and 2010 in the NHS, making the NJR the largest orthopaedic registry in the world. This powerful audit tool collects information on preoperative, intraoperative and postoperative variables, enabling advancement in most of, if not every, facet of the procedure. These data can be used to inform surgeons and other healthcare providers, healthcare commissioners, industry, and patients themselves about outcomes and best practice, ensuring informed decision-making. Drawing from NJR reports, as well as work from external authors using these data, the aim of this review is to highlight what knee surgeons can learn from 22 years of the NJR. We will discuss trends in knee surgery, changes in surgical technique, surgical outcomes and future developments.