Our multi-disciplinary team of surgeons and engineers will present the mechanisms of failure of 100 retrieved dual taper hip arthroplasties, identifying surgical, implant and patient risk factor

Bills, Paul J.

Blunn, Gordon

de Villiers, Danielle

Di Laura, Anna

Hart, A. J.

Henckel, Johann

Hothi, Harry

Kwon, Young-Min

Meswania, Jay

Racasan, Radu

Skinner, John

Whittaker, Robert

English

University of Huddersfield Repository

University of Huddersfield RepositoryDi Laura, Anna, Whittaker, Robert, Hothi, Harry, Meswania, Jay, Henckel, Johann, de Villiers, Danielle, Kwon, Young-Min, Racasan, Radu, Bills, Paul J., Blunn, Gordon, Skinner, John and Hart, A. J.Understanding Why Dual-Taper Hips FailOriginal CitationDi Laura, Anna, Whittaker, Robert, Hothi, Harry, Meswania, Jay, Henckel, Johann, de Villiers, Danielle, Kwon, Young-Min, Racasan, Radu, Bills, Paul J., Blunn, Gordon, Skinner, John and Hart, A. J. (2016) Understanding Why Dual-Taper Hips Fail. In: American Academy of Orthopaedic Surgeons Annual Meeting, 1-5 March 2016, Orlando, USA. This version is available at http://eprints.hud.ac.uk/27280/The University Repository is a digital collection of the research output of theUniversity, available on Open Access. Copyright and Moral Rights for the itemson this site are retained by the individual author and/or other copyright owners.Users may access full items free of charge; copies of full text items generallycan be reproduced, displayed or performed and given to third parties in anyformat or medium for personal research or study, educational or not-for-profitpurposes without prior permission or charge, provided:• The authors, title and full bibliographic details is credited in any copy;• A hyperlink and/or URL is included for the original metadata page; and• The content is not changed in any way.For more information, including our policy and submission procedure, pleasecontact the Repository Team at: E.mailbox@hud.ac.uk.http://eprints.hud.ac.uk/Understanding Why Dual-Taper Hips Fail Anna Di Laura¹, Robert Whittaker¹, Harry Hothi¹, Jay Meswania¹,  Johann Henckel¹, Danielle de Villiers¹, Young-Min Kwon², Radu Racasan³, Paul Bills³, Gordon Blunn¹, John Skinner¹, Alister Hart¹  Consulting/Royalty payment has been received directly related to products discussed  ¹Institute of Orthopaedics and Musculoskeletal Science, University College London, UK ²Massachusetts General Hospital/Harvard Medical School, Boston, USA ³Centre for Precision Technologies, University of Huddersfield, Huddersfield, UK Advantages: biomechanical, mixing of materials, facilitation of revision arthroplasty [1];  Disadvantages: mechanical failure [2], metal  ion release [3], corrosion at the    modular interface [4], bony erosion [5]. Dual-taper systems  SE 07  Our Study We prospectively recruited 100 patients with failed dual taper hips, collecting pre, intra and post op data to determine the clinical category of failure. Pre-revision blood metal ion levels were measured using ICPMS and, in a proportion of patients, CT was used for component position analysis and MRI was used for soft tissue analysis.          Progressive erosion of the greater trochanter (red arrows) on plain radiographs at 12, 18 and 48 months after implantation. Histology of a specimen from the synovial bursa, greater  trochanter reveals  the presence of metal particles in  giant cells and macrophages.  MARS  MRI showing pseudotumor  formation.  Our Methods Macroscopic inspection and light microscopy was performed to assess the severity of surface damage of each stem (both male and female parts) using a previously published scoring method [6]. A measurement method, using a roundness measuring machine was developed to quantify the severity of the damage on round ends of the tapers. With this method five longitudinal traces were taken on each round section of the taper surface to compute the relative depth of damage.  These traces were normalised relative to unaffected surface of the taper and a sectional wear area was computed. Average area of these five traces provided a measure of surface damage for comparative purposes. The result obtained was normalised with time in situ.  2D 3D Multi Scale Metrology Approach Computer Tomography - Industrial microCT Coordinate Measuring Machine  Optical measurements • 1500 slices to provide reconstruction of 3D model  • Reconstruct the virtual assembly between components  • Provides framework for data fusion of multi scale data from CMM and optical measurements • 400 vertical scans at 0.05mm point spacing  • Reconstruction of original geometry based on iterative best fit algorithm and unworn sections   • Resolution enables estimation of overall material loss volume and linear penetration • Form, roughness measurements based on infinite focus variation  • Estimation of local material loss volume/linear penetration  • Ability to compute 2D/areal surface parameters to investigate changes in surface texture What we See on the Neck Deepest areas of damage were found on the inferior proximal and superior distal part of the neck, compatible with bending. Scanning Electron Microscopy with Energy Dispersive Spectroscopy revealed that the surface deposit was chromium orthophosphates indicative of corrosion processes and presence of metal transfer from the stem to the neck. 3-Dimensional map  of the lateral round surface of the neck. Deepest area of damage in blue. Positive feature Positive feature 3-Dimensional map  of the medial round surface of the neck. Deepest area of damage in blue. What we See on the Stem The symmetry of the patterns found on stem bore tapers confirms micromotion between the parts with subsequent material loss due to a cantilever bending effect which is sufficient to cause adverse tissue reactions. Negative feature Negative feature 3-Dimensional map of the lateral round surface of the of the stem bore taper. Deepest area of damage in blue. 3-Dimensional map  of the medial round surface of the of the stem bore taper. Deepest area of damage in blue. References  1. Krishnan H, Krishnan SP, Blunn G, Skinner JA, Hart AJ. Modular neck femoral stems. Bone & Joint Journal. 2013 Aug 1;95(8):1011-21.2.  2. Wright G, Sporer S, Urban R, Jacobs J. Fracture of a modular femoral neck after total hip arthroplasty. The Journal of Bone & Joint Surgery. 2010 Jun 1;92(6):1518-21. 3. Nawabi DH, Do HT, Ruel A, Lurie B, Elpers ME, Wright T, Potter HG, Westrich GH. Comprehensive Analysis of a Recalled Modular Total Hip System and Recommendations for Management. J Bone Joint Surg Am. 2016 Jan 6;98(1):40-7. 4. Walsh CP, Hubbard JC, Nessler JP, Markel DC. Revision of Recalled Modular Neck Rejuvenate and ABG Femoral Implants. The Journal of arthroplasty. 2015 May 31;30(5):822-6. 5. De Martino I, Assini JB, Elpers ME, Wright TM, Westrich GH. Corrosion and Fretting of a Modular Hip System: A Retrieval Analysis of 60 Rejuvenate Stems. The Journal of arthroplasty. 2015 Aug 31;30(8):1470-5. 6. Goldberg JR, Gilbert JL, Jacobs JJ, Bauer TW, Paprosky W, Leurgans S. A multicenter retrieval study of the taper interfaces of modular hip prostheses. Clinical orthopaedics and related research. 2002 Aug 1;401:149-61. 7. Ellman MB, Levine BR. Fracture of the modular femoral neck component in total hip arthroplasty. The Journal of arthroplasty. 2013 Jan 31;28(1):196-e1. Influencing Factors  Surgeons should avoid long varus necks if opting for a dual-taper implant.  urgical mplant atient The mismatch of materials at the junction seems to avoid catastrophic breakage of the necks as reported with Ti-Ti junctions [7], however we see corrosion at the neck-stem junction in all the designs having CoCr necks and Ti stems. The severity of surface damage appears to be associated with increasing patient BMI.  The amount of damage seen on the taper associated with the stem, was severe in almost all cases examined.  

Understanding Why Dual-Taper Hips Fail

Understanding Why Dual-Taper Hips Fail

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