Combined and hybrid marker models for radiostereometry assessment of polyethylene liner motion in dual mobility hip prosthesis: a proof-of-concept study

Background Investigation of polyethylene liner movement in total hip arthroplasty requires bead-marking for radiographic visibility of the liner. However, occlusion of markers poses a challenge for marker registration in radiographs. Methods The polyethylene of a dual mobility acetabular system was marked with twelve 1-mm tantalum markers (four groups of three markers) using a custom-made drill guide. Liner motion in a phantom and a patient was investigated with dynamic radiostereometry analysis (dRSA) at 1-year follow-up and static radiostereometry analysis (sRSA) postoperatively and at 1- and 2-year follow-up. A combined marker configuration (CMC) model was calculated from the registered positions of the liner markers and the femoral head in several images. Furthermore, the CMC model and the theoretic marker positions from computer-assisted models of the drill guide were combined in a hybrid model. Results The CMC model included eleven markers in the phantom and nine markers in the patient, which was sufficient for dRSA. Liner movement in the phantom followed liner contact with the femoral neck, while liner movement in the patient was independent. The hybrid model was necessary to determine liner orientation in sRSA recordings, which clearly changed from postoperative to 1- and 2-year follow-up even though the patient was positioned similarly. Conclusion Polyethylene liner motion in dual mobility hip prosthesis can be assessed with CMC models in dRSA recordings. In sRSA, the liner position between follow-ups is unpredictable and analysis requires inclusion of all markers in the model, accomplished with a hybrid marker model. Trial registration ClinicalTrials.gov [NCT02301182], 25 October 2015.

Using an asymmetric crosslinked polyethylene liner in primary total hip arthroplasty is associated with a lower risk of revision surgery

Aims The aim of our study was to investigate the effect of asymmetric crosslinked polyethylene liner use on the risk of revision of cementless and hybrid total hip arthroplasties (THAs). Methods We undertook a registry study combining the National Joint Registry dataset with polyethylene manufacturing characteristics as supplied by the manufacturers. The primary endpoint was revision for any reason. We performed further analyses on other reasons including instability, aseptic loosening, wear, and liner dissociation. The primary analytic approach was Cox proportional hazard regression. Results A total of 213,146 THAs were included in the analysis. Overall, 2,997 revisions were recorded, 1,569 in THAs with a flat liner and 1,428 in THAs using an asymmetric liner. Flat liner THAs had a higher risk of revision for any reason than asymmetric liner THAs when implanted through a Hardinge/anterolateral approach (hazard ratio (HR) 1.169, 95% confidence interval (CI) 1.022 to 1.337) and through a posterior approach (HR 1.122, 95% CI 1.108 to 1.346). There was no increased risk of revision for aseptic loosening when asymmetric liners were used for any surgical approach. A separate analysis of the three most frequently used crosslinked polyethylene liners was in agreement with this finding. When analyzing THAs with flat liners only, THAs implanted through a Hardinge/anterolateral approach were associated with a reduced risk of revision for instability compared to posterior approach THAs (HR 0.561 (95% CI 0.446 to 0.706)). When analyzing THAs with an asymmetric liner, there was no significant difference in the risk of revision for instability between the two approaches (HR 0.838 (95% CI 0.633 to 1.110)). Conclusion For THAs implanted through the posterior approach, the use of asymmetric liners reduces the risk of revision for instability and revision for any reason. In THAs implanted through a Hardinge/anterolateral approach, the use of an asymmetric liner was associated with a reduced risk of revision. The effect on revision for instability was less pronounced than in the posterior approach. Cite this article: Bone Joint J 2021;103-B(9):1479–1487.

Polyethylene liner dissociation in a DePuy pinnacle cup with a manufacturer analysis of the failed component

A 74-year-old patient presented to the emergency department with acute atraumatic hip pain 9 years after her primary left total hip arthroplasty (THA). Plain radiographic imaging demonstrated lateralisation of the femoral head within the acetabular shell—indicating an issue with the polyethylene liner. The patient required revision of the acetabular component and the femoral head, as well as a new polyethylene liner. A detailed analysis of the components removed was performed by DePuy Synthes Engineering. Between 2009 and 2020, 8 publications have documented 52 cases of liner dissociation with the Pinnacle acetabular component and Marathon polyethylene liner. Various theories have been proposed in the literature as all of these components appear to fail in the same way, with shearing of the locking tabs in the polyethylene liner. In spite of a manufacturer analysis of the components, no root cause was identified as to why the polyethylene liner failed.

The Wear Rate and Survivorship in Total Hip Arthroplasty using a Third- Generation Ceramic Head on a Conventional Polyethylene liner: A Minimum of 15-year Follow-up

Background: Recently, the use of ceramic-on-polyethylene (CoP) bearing surfaces has increased in the United States with the development of material properties. However, it remains controversial which bearing couples are effective. The purpose of this study was to evaluate the wear and survival rates of third-generation ceramic heads on a conventional polyethylene liner. Methods: We retrospectively reviewed 160 hips (147 patients with a mean age of 56 years) who underwent total hip arthroplasty using the third-generation ceramic head on a conventional polyethylene liner from March 1998 to August 2003. The wear rate was evaluated using the PolyWare program Version 8 (Draftware Developers Inc., IN, USA) in 32 hips followed-up for at least 15 years. In addition, we evaluated the Kaplan-Meier survivorship.Results: Linear wear and volumetric wear rates were 0.102±0.57 mm/year and 30.2±27.5 mm3/year, respectively. Fourteen reoperations due to all causes and 10 revisions were performed during the follow-up period. The 15-year survival rate was 84.1% for any surgery as the endpoint and 87.6% for the revision surgery as the endpoint. Most of the causes of revision were cup loosening, and no ceramic head fracture occurred.Conclusions: The CoP bearing surface maintains the advantages of the soft polyethylene surface and has good resistance to wear. Therefore, alumina ceramic on newer polyethylene could certainly be a good alternative bearing couple without any concern for ceramic fractures, especially in younger patients.Level of evidence: Level III, retrospective cohort design

Femoral head penetration in Vitamin-E polyethylene liner versus conventional liners in total hip arthroplasty: systematic review and meta-analysis of randomised control trials

Background: Debate encompasses the use of Vitamin E Polyethylene or conventional Polyethylene liner in primary hip arthroplasty. Does the Inclusion of Vitamin E in PE give adequate protection from oxidation and maintains lower rates of wear? Patients and methods: We performed this study following the Preferred Reporting Items for Systematic Reviews and Meta-analyses Statement (PRISMA) and the Cochrane Handbook for systematic reviews and meta-analysis. Studies were included from any region, written in any language. We had only the randomised control trials comparing the femoral head penetration between Vitamin-E diffused highly cross-linked polyethylene (VEPE) liner and conventional liners in primary total hip arthroplasty. Results: We included 10 studies in this meta-analysis. We conducted them using Review Manager V.5.0. We computed the risk ratio to measure the treatment effect, considering the heterogeneity. We used Random-effect models. VEPE had insignificant marginal advantages for FHP within three months post-operative. Additionally, VEPE showed significantly less FHP after two and five years. After one year, it showed significantly less FHP with the VEPE group versus the UHMWPE cohort and a non-significant difference between the VEPE and XLPE group. Conclusions: In terms of FHP, this metanalysis shows less FHP for the VEPE than conventional PE. A longer follow-up period is required to evaluate whether the oxidation protection gained by Vitamin E results in lower wear rates, less osteolysis, and aseptic loosening compared to the conventional PE in the long term.