A multinational assessment of metal-on-metal bearings in hip replacement

Journal Journal of Bone and Joint Surgery, American Volume
Authors Graves, Stephen; Rothwell, Alastair; Tucker, Keith; Jacobs, Joshua; Sedrakyan, Art
Year Published 2011
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Abstract

There is emerging evidence that many metal-on-metal (MoM) bearings, when used with large femoral heads in conventional hip replacement and some resurfacing prostheses, are associated with increased rates of revision arthroplasty. Registries are the main sources of data on MoM prostheses. At the recent International Consortium of Orthopaedic Registries (ICOR) meeting, data were presented from the Australian, England and Wales, and New Zealand registries. All registries reported an increased rate of revision for large femoral head MoM prostheses when prostheses were aggregated compared with the aggregated data of hip prostheses with other bearing surfaces. There was also evidence, however, that the outcome varied, depending on the type of prostheses used, in both large femoral head MoM conventional hip replacement as well as resurfacing hip replacement.The relevance of the recent isolated case reports on systemic metal toxicity was also discussed at the ICOR meeting. Although systemic metal toxicity appears to be a rare occurrence, there is a need to undertake appropriately designed studies to define the true prevalence of this phenomenon. There may be advantages in nesting these studies within registries. The ICOR meeting highlighted the implications of the MoM experience for the orthopaedic industry, regulators, and surgeons.

Effect of femoral head size on metal-on-HXLPE hip arthroplasty outcome in a combined analysis of six national and regional registries

Journal Journal of Bone and Joint Surgery, American Volume
Authors Allepuz, Alex; Havelin, Leif; Barber, Thomas; Sedrakyan, Art; Graves, Stephen; Bordini, Barbara; Hoeffel, Daniel; Cafri, Guy; Paxton, Elizabeth
Year Published 2014
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Abstract

BACKGROUND: HXLPE (highly cross-linked polyethylene) has greater wear resistance compared with UHMWPE (ultra-high molecular weight polyethylene), which may contribute to improving the outcomes of total hip arthroplasty with a large femoral head. However, no information is available regarding the effect of femoral head size on the survivorship of HXLPE hip prostheses. The aim of the present study was to provide evidence regarding whether femoral head size has an effect on the risk of revision when an HXLPE liner is used on a metal head.

METHODS: A distributed health data network was developed by the ICOR (International Consortium of Orthopaedic Registries). Six national and regional registries are participating in this network: Kaiser Permanente, HealthEast, the Emilia-Romagna region in Italy, the Catalan region in Spain, Norway, and Australia. Data from each registry were standardized and provided at an aggregate level for each of the variables of interest. Patients with osteoarthritis who were forty-five to sixty-four years of age and had undergone uncemented total hip arthroplasty were included in the present study. Analyses were performed on the basis of individual patient profiles, utilizing the variables collected from each registry. The outcome of interest was the time to the first revision (for any reason). Survival probabilities and their standard errors were extracted from each registry for each unique combination of the covariates and were combined through multivariate meta-analysis utilizing linear mixed models to compare survivorship for <32-mm, 32-mm, and >32-mm femoral head sizes.

RESULTS: A total of 14,372 total hip arthroplasties were included in the study. The five-year rate of revision surgery varied from 1.9% to 3.2% among registries. The risk of revision did not differ significantly between < 32-mm and 32-mm head sizes (HR [hazard ratio] = 0.91, 95% CI [confidence interval] = 0.69 to 1.19) or between > 32-mm and 32-mm sizes (HR = 1.05, 95% CI = 0.70 to 1.55).

CONCLUSIONS: The results of our study provide relevant data to orthopaedic surgeons deciding on the use of a larger articulation in a metal-on-polyethylene bearing. A larger head diameter should not be considered a detriment to device survival when an HXLPE liner is used. However, efforts to force the use of a large-size implant appear unsupported, as similar survivorship was observed for all head diameter groups.

Comparative effectiveness of ceramic-on-ceramic implants in stemmed hip replacement: a multinational study of six national and regional registries

Journal Journal of Bone and Joint Surgery, American Volume
Authors Sedrakyan, Art; Graves, Stephen; Bordini, Barbara; Pons, Miguel; Havelin, Leif; Mehle, Susan; Paxton, Elizabeth; Barber, Thomas; Cafri, Guy
Year Published 2014
Link to article

Abstract

BACKGROUND: The rapid decline in use of conventional total hip replacement with a large femoral head size and a metal-on-metal bearing surface might lead to increased popularity of ceramic-on-ceramic bearings as another hard-on-hard alternative that allows implantation of a larger head. We sought to address comparative effectiveness of ceramic-on-ceramic and metal-on-HXLPE (highly cross-linked polyethylene) implants by utilizing the distributed health data network of the ICOR (International Consortium of Orthopaedic Registries), an unprecedented collaboration of national and regional registries and the U.S. FDA (Food and Drug Administration).

METHODS: A distributed health data network was developed by the ICOR and used in this study. The data from each registry are standardized and provided at a level of aggregation most suitable for the detailed analysis of interest. The data are combined across registries for comprehensive assessments. The ICOR coordinating center and study steering committee defined the inclusion criteria for this study as total hip arthroplasty performed without cement from 2001 to 2010 in patients forty-five to sixty-four years of age with osteoarthritis. Six national and regional registries (Kaiser Permanente and HealthEast in the U.S., Emilia-Romagna region in Italy, Catalan region in Spain, Norway, and Australia) participated in this study. Multivariate meta-analysis was performed with use of linear mixed models, with survival probability as the unit of analysis. We present the results of the fixed-effects model and include the results of the random-effects model in an appendix. SAS version 9.2 was used for all analyses. We first compared femoral head sizes of >28 mm and ≤28 mm within ceramic-on-ceramic implants and then compared ceramic-on-ceramic with metal-on-HXLPE.

RESULTS: A total of 34,985 patients were included; 52% were female. We found a lower risk of revision associated with use of ceramic-on-ceramic implants when a larger head size was used (HR [hazard ratio] = 0.73, 95% CI [confidence interval] = 0.60 to 0.88, p = 0.001). Use of smaller-head-size ceramic-on-ceramic bearings was associated with a higher risk of failure compared with metal-on-HXLPE bearings (HR = 1.36, 95% CI = 1.09 to 1.68, p = 0.006). Use of large-head-size ceramic-on-ceramic bearings was associated with a small protective effect relative to metal-on-HXLPE bearings (not subdivided by head size) in years zero to two, but this difference dissipated over the longer term.

CONCLUSIONS: Our multinational study based on a harmonized, distributed network showed that use of ceramic-on-ceramic implants with a smaller head size in total hip arthroplasty without cement was associated with a higher risk of revision compared with metal-on-HXLPE and >28-mm ceramic-on-ceramic implants. These findings warrant careful reflection by regulatory and clinical communities and wide dissemination to patients for informed decision-making regarding such surgery.