French hip resurfacing registry: A study of 1650 cases.

Background: Hip resurfacing has been the focus of many evaluations based on international registries but, to date, no prospective studies have evaluated this procedure in France. In 2015, the French Society for Orthopaedics and Traumatology (SoFCOT) and the French Hip and Knee Society concluded an agreement with the French Medicines Agency (ANSM) and French National Health Authority (HAS) to establish an exhaustive observational hip resurfacing registry. The primary objective of this study was to evaluate the hip resurfacing survival rate since the creation of the registry 5 years ago. The secondary objectives were to evaluate the clinical, functional, and radiological outcomes of hip resurfacing and to check the absence of specific complications related to this implant.

Hypothesis: The hypothesis was that the registry survival rate was below 0.5% per year.

Methods: Since 2015, data from all patients undergoing hip resurfacing were collected into a monitored database using the software suite OrthoWave. The following were collected for each patient: demographics, anthropometric characteristics, clinical parameters (Postel Merle d'Aubigné score, Harris Hip Score, Oxford Hip Score, and UCLA Activity Score), and radiological findings. Completeness of data collection was checked once a year.

Results: In total, 1650 hip resurfacings in 1506 patients (1409 males and 97 females) with a mean age of 50.7 years (range, 17-70 years) were included. Mean follow-up was 3.8 years (range, 2-4.8 years). Mean completeness of data recording was 98.2%. All clinical scores improved significantly. Hip revision was required for 7 (0.4%) complications including 4 femoral neck fractures, 1 aseptic lymphocyte-dominant vasculitis-associated lesion with a large joint effusion, 1 femoral component loosening, and 1 delayed sepsis requiring bipolar removal. At 5 years, the survival rate without hip revision for any cause was 99.6% (95% confidence interval, 99.3-100%).

Discussion: The short-term outcomes of patients in the French registry are encouraging in terms of complication and surgical revision rates. The near absence of complications related to metal-on-metal bearing surfaces demonstrates that the criteria used in France (at least 48mm head diameter, use of implants for which long-term data are available, and specific training of surgeons) ensure successful long-term outcomes.

Level Of Evidence: II.