Understanding the dual mobility concept for total hip arthroplasty. Investigations on a multiscale analysis-highlighting the role of arthrofibrosis

Abstract

International audienceIn hip implants, UHMWPE (ultra high molecular weight polyethylene) liner wear is believed to be a key issue affecting the lifetime of the artificial joint. Dual mobility, a THA (total hip arthroplasty) concept where the liner moves inside the metallic shell, has become popular due to its low dislocation rate. To understand the tribological behavior of this particular implant, especially the role of the second mobility, 12 representative explants were selected from a bank of 250 explants. The implants used were Profil® femoral stem and Novae® metallic shell. The external surface, involved in the second mobility, was examined by 3D profilometry, SEM (scanning electron microscopy) and CMM (coordinate measuring machine). This study highlights a correlation between roughness and CMM evolutions and surgical parameters. A particular wear zone and a wear scenario were identified and validated according to the type of metal-back. A metal transfer between the metal back and the liner was isolated. CMM allowed to measure second mobility wear volume at a macroscopic scale. Thus a realistic wear mechanism has been suggested for this specific implant

Wear of dual-mobility cups: a review article

“…This may be due to a larger-diameter surface or because the measurement probe cannot reach the upper border of the inner poly, thus leaving behind data regarding the retentive rim. Similar wear values were estimated by Geringer et al [33], who analyzed 12 UHMWPE components of the same hip design using a coordinate measurement machine (CMM) with a 1-mm probe. Annual wear was 36.7 ± 29.1 mm 3 /year for the convex side, 22.1 ± 39.2 mm 3 /year for the concave side and estimated total annual wear was 53.9 ± 50.30 mm 3 /year.…”

Intraprosthetic Dislocation: A Specific Complication of the Dual-mobility System

“…After initial enhancement of primary fixation and secondary osseointegration of the acetabular cup achieved in 1993, the reported survival rates of 90% to 96% at 12 to 22 years [2,17,19,20] were similar to those reported with noncemented implants [4,9,10]. In 1998 the polyethylene (PE) liners were changed by increasing crosslinking to reduce PE wear rate [7] although before that time the wear rates (approximately 70 mm 3 /year [1,8]) were comparable to those reported in the literature with metal and conventional PE bearing couples [1]. Finally, in 2001 the design of the acetabular cup was improved by decreasing the anterior overhang and increasing the press fit to achieve better primary fixation and avoid mechanical conflict with the iliopsoas tendon.…”

“…All explants were collected and analyzed by one of the authors (BB). Parts of the data already were reported [8].…”

Fundamentals of Linking Tribology and Corrosion (Tribocorrosion) for Medical Applications: Bio-tribocorrosion

“…The application of tribocorrosion in the biomedical field has since created bio-tribocorrosion as a critical area of research that has made significant progress during the last 5 years. The strong efforts by Mischler et al [1,7,9,10,17,18], Geringer et al [19][20][21][22][23][24], Rocha et al [4,[25][26][27][28][29][30], and Yan et al [2,5,31,32] have provided a clear direction for scientists and clinicians. Currently, tribocorrosion is being studied by many research groups in Europe and is becoming prominent in other countries including the USA and Brazil.…”