Short summary

This is a register study based on the prospectively collected data from the DHR which will be compared to the data registered in the electronic patient medical records in Denmark.. The study includes 2,000 primary THA ( Total Hip arthroplpasty) patients and 1,500 revision THA patients. The purpose is to validate the registered data i DHR regarding the indication of revision hip arthroplasty operations and to define the true THA population.

Rationale

The Danish Hip Arthroplasty Register (DHR) was founded in 1995. Today, 11.000 primary total hip arthroplasties (THA) and 1.300 hip revision arthroplasties are registered in the DHR annually, and since 1995 a total of 245.161 operations have been registered. The overall purpose of the DHR is to contribute to the continuous improvement of treatment quality for patients undergoing hip replacement. The completeness of the DHR is generally high, as registration is compulsory. The registered data in the DHR has founded the basis for many research studies, both nationally and abroad as an important part of the Nordic Arthroplasty Register Association (NARA) . The large amount of data prospectively collected throughout the past two decades has provided orthopedic researchers with unique possibilities to study complications occurring several years after the surgical procedure. The register is in particular considered the golden standard in detecting rare complications due the large populations that can be extracted - complications that would not be possible to discover in clinical studies. The results are continuously applied to refine and adapt the use of particular implant types to specific patient subgroups to lower the risk of complications. However, only a minor part of the DHR data has been validated , and consequently, we are currently not able to define the true THA population leading to a potential risk of making erroneous conclusions and adopt inferior treatment strategies. The purpose of this study is to define the "true" THA population, and hence increase the reliability of the results of studies already using DHR primary and revision data or will be using these data in the future. This study is of great societal importance due to the large population of patients receiving THAs every year, and it will identify inferior treatment strategies and thereby decrease the risk of devastating complications by influencing decision making now and in the future

Description of the cohort

The study is nationwide and will include 2,000 primary THA patients and 1,500 revision THA patients from every region in Denmark. The patients will be randomly chosen from the list of reported operations to the DHR in the five-year period from January 1st, 2018 to December 31st, 2022. The patients will be equally distributed between the five regions of Denmark, and regarding the revision patients, also evenly distributed between the following ten different indications for revision, where (infection) is excluded, as this particular indication has been studied by Gundtoft et al (9): 1. Polyethylene wear without aseptic loosening 2. Dislocation 3. Peri-prostic fracture 4. Others 5. Pain 6. Aseptic loosening of both femoral and acetabular components of the prosthesis 7. Aseptic loosening of the acetabular component of the prosthesis alone 8. Aseptic loosening of the femoral component of the prosthesis alone 9. Osteolysis/ granuloma without loosening 10. Component failure Therefore, we intend to include about 700 patients from each region, allocated to 400 primary and 300 revision THA. In order to define the "true" THA population, we will map the population in terms of both patient information (Date of surgery, Laterality, Procedure (primary/revision), Indication for revision, BMI and ASA-score) and implant-related information (Cemented/un-cemented (acetabular and femoral component), Head size, Liner type, Liner cross-linked or not, Extent of revision)

Data and biological material

This is a register study based on the prospectively collected data from the DHR, which will be compared to the data registered in the electronic patient medical records in Denmark. The study will adhere to the Reporting of studies Conducted using Observational Routinely-collected Data (RECORD) guidelines

Collaborating researchers and departments

Department of Orthopedics University Hospital of Southern Denmark, Esbjerg

• Ammar Ali
• Lars Lykke Hermansen

Department of Orthopaedic Surgery and Traumatology, Copenhagen University Hospital, Bispebjerg

• Soeren Overgaard