The premature failure of the Charnley Elite-Plus stem

Abstract

The Journal of Bone and Joint Surgery. British volumeVol. 88-B, No. 12 CorrespondenceFree AccessThe premature failure of the Charnley Elite-Plus stemG. H. ISAACG. H. ISAACSenior Engineering FellowSearch for more papers by this authorPublished Online:1 Dec 2006https://doi.org/10.1302/0301-620X.88B12.18855AboutSectionsPDF/EPUB ToolsDownload CitationsTrack CitationsPermissionsAdd to Favourites ShareShare onFacebookTwitterLinked InRedditEmail Sir,I read with interest the article by Hauptfleisch et al.1 DePuy International Ltd has to date not commented on the data presented by the authors, in various publications, on the performance of the Elite-Plus system. However, we consider that the publication of the above paper requires a response because firstly, the conclusions may cause unnecessary concern to surgeons who have used the Elite-Plus system and the many thousands of patients who have been the recipients of this device. Secondly, information pertinent to the conclusions of this paper was omitted by the authors in the original publication.The results presented in the above publication were derived from a research study which was designed by the Oxford group and grant-funded by DePuy International Ltd. The outcome of this RSA-like study was followed closely. The results were openly shared and discussed between our research groups. When the two-year follow-up data became available, this was reviewed. It appeared that the posterior migration/rotation of the Elite-Plus stems was greater than that of the comparator system. An examination of the data showed that the difference in posterior migration was not a normal distribution and that four outliers were the principle cause of the difference. If these were excluded then the two cohorts had similar levels of posterior migration. In an attempt to explain these differences a representative of DePuy (GHI), who had no prior access to the outcome data for individual patients, was invited to review 14 sets of Elite-Plus radiographs from the study. A number of factors were reviewed, including stem position, orientation, cement mantle thickness, and cement mantle quality.A notable observation was that nine of ten patients in the stable group were registered as having a good cement mantle (as opposed to satisfactory), whilst only one of four was recorded in the unstable group. A further observation was that three patients were identified as having inadequate proximomedial cement support (“virtually no cement mantle”, “very little cement”, and “low neck resection”). When these patients were matched with the RSA data it was found that they were contained within the group of four that had higher than average posterior migration. These observations (together with others) on the appearance of the cement mantle were communicated, verbally and in writing, to the authors who concluded “none of your measurements have a significant relationship to posterior head migration”. A further communication was sent to the authors highlighting the relevant observations and concluding, “whilst not proven, these small numbers hint that the quality of the cement mantle may be a factor which influences stability”, and that the majority of stems with high posterior movement had “radiographic features which would make instability more likely”. Further comments were sought, however,not only the current paper1 but also a previous publication on this study2 completely ignored these issues, and the relationship to radiographic appearance was not discussed.Given the radiographic appearance it is not entirely surprising that these high posterior migration components subsequently went on to fail. Furthermore, it reinforces the belief that the performance of cemented stems is as much dependent upon the quality of cementation as it is on stem design. References 1 Hauptfleisch J, Glyn-Jones S, Beard DJ, Gill HS, Murray DW. The premature failure of the Charnley Elite-Plus stem: a confirmation of RSA predictions. J Bone Joint Surg [Br] 2006;88-B:179–83. Link, Google Scholar2 Alfaro-Adrian J, Gill HS, Murray DW. Should total hip arthroplasty femoral components be designed to subside? A radiostereometric analysis study of the Charnley and Exeter stems. J Arthroplasty 2001;16:598–606. Crossref, Medline, ISI, Google ScholarFiguresReferencesRelatedDetails Vol. 88-B, No. 12 Metrics History Published online 1 December 2006 Published in print 1 December 2006 InformationCopyright © 2006, The British Editorial Society of Bone and Joint Surgery: All rights reservedPDF download