Usefulness of a Cementless Highly-Porous Acetabular Cup in Rheumatoid Arthritis Patients Undergoing Total Hip Arthroplasty.

Abstract

Background: Total hip arthroplasty in patients with rheumatoid arthritis is difficult and leads to worse implant survival and higher risk for complications compared to osteoarthritis. Poor periacetabular bone quality might challenge the stability of the acetabular cup. Contemporary 3D-printed highly-porous titanium cup designs have become the benchmark for cementless implants; however, their usefulness in rheumatoid arthritis is still unclear. The purpose of this study was to assess the short-term results of the use of a highly-porous 3D-printed acetabular titanium cup in patients with rheumatoid arthritis.

Material and methods: We studied a consecutive series of RA patients who underwent cementless THA between 2019 and 2020 in our center with the same 3D-printed highly-porous titanium acetabular cup. All patients were evaluated prospectively for a minimum 3-year follow-up with the Harris hip score, VAS and Roles and Maudsley score. Radiographic assessment focused on evidence of cup osseointegration.

Results: 37 RA patients, mean age at surgery of 51.3 years, were included. Mean follow-up was 3.2 years (3 to 4 years). By the last follow-up visit, the Harris hip score had increased significantly from 37.8 to 88.5, VAS had decreased from 6.1 to 1.0 and excellent satisfaction for 31 patients. All 5 Moore's radiographic signs were present in 35 hips, with only 4 signs present in the remaining 2 hips, thus indicating complete osseointegration of all cups. There were no complications on the acetabular side but one intraoperative proximal calcar fracture.

Conclusion: 3D-printed highly porous implants used in primary THA worked well in patients with rheumatoid arthritis, showing excellent osseointegration and good clinical results in the short term.