Epidemiological Studies in Orthopaedics

Registries

Arthroplasty registries, designed initially to identify poorly performing implants, have led the way in terms of collecting national-level longitudinal data on individuals undergoing an orthopaedic intervention. The Swedish Arthroplasty Register is the oldest joint registry in the world and, since its creation, the number of worldwide registries has increased. The National Joint Registry of England and Wales (NJR) is the largest arthroplasty registry with over a million recorded procedures. In the UK, there are now several other orthopaedic registries including the Non-Arthroplasty Hip Register, the UK National Ligament Registry, the UK Knee Osteotomy Registry, the National Hip Fracture Database and the British Spine Registry. In addition to monitoring for failure and assessing epidemiological trends, outcomes of interventions and identification of patient- or treatment-related risk factors for poor outcomes are key analysis outputs from registry data. Expansion of data collection such as the inclusion of patient-reported outcomes measures (PROMS) provides the ability to compare success and failure on a more clinically relevant scale. Most national-level registries produce annual reports where key demographic information is published. Surgeon-level data are also increasingly becoming available, making registry outputs hugely important on a very personal level for surgeons. Specific research questions are often addressed by independent individuals or groups applying for access to the data and undertaking the necessary analysis. The strength of using epidemiological analyses in orthopaedics is the ability to examine critically the interventions we offer as a population of clinicians working within a specific healthcare system. Problems are often highlighted by registry data at an early stage which allows appropriate changes to practice to be made. Within modern healthcare systems, the need to demonstrate the cost-effectiveness of interventions is imperative and this requires comparisons to be made, not only of clinical value, but also of value for money.