CORR Insights(®): Otto Aufranc Award: Large Heads Do Not Increase Damage at the Head-neck Taper of Metal-on-polyethylene Total Hip Arthroplasties.

L arge femoral heads offer proven benefits in reducing the risk of dislocation. However, the failure rate of metal-on-metal (MoM) THA increases with head size, and is even larger than hip resurfacing cases using the same design of articulation [1, 3]. This appears to be due to an increased generation of corrosion products at the modular head-neck junction [6]. The question is whether the risk of inflammatory reactions secondary to trunnion wear and corrosion will also increase when larger heads (> 32 mm) are implanted with metal-on-polyethylene (MoP) articulations. Previous studies on this topic have examined relatively small numbers of implants (50 to 80), with conflicting conclusions both in favor [4, 7] and against [5] an association between larger heads and increased fretting and/or corrosion of modular head-neck junctions. The current study by Triantafyllopoulos and colleagues is part of an ongoing investigation on total joint arthroplasty that addresses one fundamental question: What combination of implant materials, design features, and surgical practices is required to eliminate tissue reactions at modular junctions, preferably with minimal disruption of current procedures? This study has presented interesting data derived from a long-term retrieval collection, which illuminates some of the contemporary controversies in implant performance and its mechanisms of failure. One of the strengths of the study was that the authors examined a broad assortment of MoP components (n = 154) with six different taper designs and a wide assortment of head sizes, ranging from 22 mm to 44 mm, with 80% B 32 mm. The duration of implantation was also considerable, ranging from a few months to more than 20 years in vivo. They concluded that although fretting or corrosion of the head and the trunnion were common, they were not associated with differences in head size. This CORR Insights is a commentary on the article ‘‘CORR Insights Otto Aufranc Award: Large Heads Do Not Increase Damage at the Head-neck Taper of Metal-onpolyethylene Total Hip Arthroplasties by Triantafyllopoulos and colleagues available at: DOI: 10.1007/s11999-015-4468-6. The author certifies that he, or a member of his immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/ licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request. The opinions expressed are those of the writer, and do not reflect the opinion or policy of CORR or The Association of Bone and Joint Surgeons. This CORR Insights comment refers to the article available at doi:10.1007/s11999-0154468-6. P. C. Noble PhD (&) Barnhart Department of Orthopaedic Surgery, Baylor College of Medicine, 6550 Fannin, Suite 2503, Houston, TX 77030, USA e-mail: pnoble@bcm.edu CORR Insights Published online: 21 August 2015 The Association of Bone and Joint Surgeons1 2015