Date Published: June 01, 2018
Publisher: Taylor & Francis
Author(s): Gulraj S Matharu, Antti Eskelinen, Andrew Judge, Hemant G Pandit, David W Murray.
The initial outcomes following metal-on-metal hip arthroplasty (MoMHA) revision surgery performed for adverse reactions to metal debris (ARMD) were poor. Furthermore, robust thresholds for performing ARMD revision are lacking. This article is the second of 2. The first article considered the various investigative modalities used during MoMHA patient surveillance (Matharu et al. 2018a). The present article aims to provide a clinical update regarding ARMD revision surgery in MoMHA patients (hip resurfacing and large-diameter MoM total hip arthroplasty), with specific focus on the threshold for performing ARMD revision, the surgical strategy, and the outcomes following revision.
The outcomes following ARMD revision surgery appear to have improved with time for several reasons, among them the introduction of regular patient surveillance and lowering of the threshold for performing revision. Furthermore, registry data suggest that outcomes following ARMD revision are influenced by modifiable factors (type of revision procedure and bearing surface implanted), meaning surgeons could potentially reduce failure rates. However, additional large multi-center studies are needed to develop robust thresholds for performing ARMD revision surgery, which will guide surgeons’ treatment of MoMHA patients. The long-term systemic effects of metal ion exposure in patients with these implants must also be investigated, which will help establish whether there are any systemic reasons to recommend revision of MoMHAs
The poor outcomes initially reported following ARMD revision surgery (Grammatopoulos et al. 2009, de Steiger et al. 2010) led regulatory authorities and surgeons to widely recommend performing early revision in MoMHAs with ARMD (Grammatopoulos et al. 2009, De Smet et al. 2011, Haddad et al. 2011, MHRA 2012, FDA 2013). However, there are currently no robust thresholds for performing ARMD revision surgery, because of lack of evidence. Therefore surgeons have difficulty when managing patients with ARMD: which patients to revise and which to keep under surveillance?
The surgical management of ARMD has evolved over time, with the heterogeneity of ARMD not being appreciated initially (Grammatopoulos et al. 2009, De Smet et al. 2011, Liddle et al. 2013). Therefore MoMHA revisions performed for ARMD can range from simple to more complex cases (Liddle et al. 2013).
Numerous studies have now reported on the short- to medium-term risks associated with ARMD revision surgery in MoMHA patients, which can be used to counsel patients informatively pre-revision. Evidence suggests that outcomes following ARMD revision may have improved with time. The reason for this is multifactorial and may include regular patient surveillance, lowering of the threshold for performing revision, surgical experience with ARMD revisions, and patients now undergoing revision at longer intervals from primary surgery with such cases potentially being less severe compared with revisions performed early after MoMHA. However, we consider that the threshold for performing ARMD revision surgery need not be lowered much further as this introduces the potential for surgical risk to outweigh any benefits.