[Evidence-based hip prostheses: more high-quality prostheses used after introduction of a classification system]

To determine the effect of an evidence-based classification list on use of total hip prostheses of proven quality in the Netherlands.

Observational study.

The Netherlands Orthopaedic Association (NOV) drew up a classification list for total hip prostheses in 2013. This classification list considered total hip prostheses to be of proven quality when the average percent of revision was ≤ 10% after 10 years of follow-up (category 1A) or ≤ 5% after 5 years of follow-up (category 1B). Data from the Dutch National Orthopaedic Implant Registry Register (LROI) were used to determine the effect of the classification list on the use of hip prostheses of proven quality in the Netherlands. All patients, operations and prosthesis characteristics of the hip prostheses used in the Netherlands were registered in the LROI. We selected details of all interventions in which a hip prosthesis was implanted in patients with 'osteoarthritis' as primary diagnosis between 2012 and 2014 from the LROI. The prostheses could be classified as 1A, 1B or 'not 1A or 1B' by means of the implant code of the acetabular and femoral components. We took 2012 as the reference year.

In the reference year, 84% of the acetabular components and 94% of the femoral components were category 1A or 1B. In 2013 these percentages had increased to 89% and 95%, respectively; in 2014 the percentages had increased to 92% and 97%.

After implementation of the NOV classification list there was an increase in the percentage of total hip prostheses of proven quality, which means that patient care has become better and safer.