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

Peter Bo Jørgensen,Stig S Jakobsen,Maiken Stilling,Bart L Kaptein,Kjeld Søballe

doi:10.1186/s41747-021-00253-x

Peter Bo Jørgensen, Stig S Jakobsen + Show 3 more

Open Access

https://doi.org/10.1186/s41747-021-00253-x

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Abstract

BackgroundInvestigation 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.MethodsThe 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.ResultsThe 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.ConclusionPolyethylene 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 registrationClinicalTrials.gov [NCT02301182], 25 October 2015.

Highlights

Investigation of polyethylene liner movement in total hip arthroplasty requires bead-marking for radiographic visibility of the liner
Dynamic radiostereometric analysis (RSA) has been used to investigate native hip joint and total hip arthroplasty kinematics and pathomechanics, while static RSA has been used to measure polyethylene liner wear in single mobility total hip arthroplasty by insertion of tantalum markers in the PE [10, 11]
The combined marker configuration (CMC) model for the phantom was derived from five dynamic RSA frames and comprised of eleven markers

Summary

Introduction

Investigation of polyethylene liner movement in total hip arthroplasty requires bead-marking for radiographic visibility of the liner. The dual mobility acetabular system is designed to reduce dislocation rate by providing increased jump distance, increased range of motion and reduced risk of impingement [2]. It has a mobile polyethylene (PE) liner that articulates with respect to both the outer metal shell and the femoral head. The movements of the liner have been investigated experimentally and in a retrieval study but no clinical assessment of dual mobility liner kinematics in patients have been performed This is because radiographic imaging methods are challenged by PE liner radiolucency, liner symmetry and liner occlusion by metal components, bone and soft tissue [3, 4]. Dynamic RSA has been used to investigate native hip joint and total hip arthroplasty kinematics and pathomechanics, while static RSA has been used to measure polyethylene liner wear in single mobility total hip arthroplasty by insertion of tantalum markers in the PE [10, 11]

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