More than 95% completeness of reported procedures in the population-based Dutch Arthroplasty Register: External validation of 311,890 procedures

BACKGROUND AND PURPOSE: A complete and correct national arthroplasty register is indispensable for the quality of arthroplasty outcome studies. We evaluated the coverage, completeness, and validity of the Dutch Arthroplasty Register (LROI) for hip and knee arthroplasty. PATIENTS AND METHODS: The LROI is a nationwide population-based registry with information on joint arthroplasties in the Netherlands. Completeness of entered procedures was validated in 2 ways: (1) by comparison with the number of reimbursements for arthroplasty surgeries (Vektis database), and (2) by comparison with data from hospital information systems (HISs). The validity was examined by conducting checks on missing or incorrectly coded values in the LROI. RESULTS: The LROI contains over 300,000 hip and knee arthroplasties performed since 2007. Coverage of all Dutch hospitals (n = 100) was reached in 2012. Completeness of registered procedures was 98% for hip arthroplasty and 96% for knee arthroplasty in 2012, based on Vektis data. Based on comparison with data from the HIS, completeness of registered procedures was 97% for primary total hip arthroplasty and 96% for primary knee arthroplasty in 2013. Completeness of revision arthroplasty was 88% for hips and 90% for knees in 2013. The proportion of missing or incorrectly coded values of variables was generally less than 0.5%, except for encrypted personal identity numbers (17% of which were missing) and ASA scores (10% of which were missing). INTERPRETATION: The LROI now contains over 300,000 hip and knee arthroplasty procedures, with coverage of all hospitals. It has a good level of completeness (i.e. more than 95% for primary hip and knee arthroplasty procedures in 2012 and 2013) and the database has high validity.