Ongoing problems with metal-on-metal hip implants

Heneghan, Carl; Langton, David; Thompson, Matthew

doi:10.1136/bmj.e1349

Cited by 52 publications

(22 citation statements)

References 22 publications

(9 reference statements)

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“…[16] [17] Although several groups have published findings supporting metal-on-metal hip resurfacing when performed by experienced centres on young men with appropriate anatomy, [17] [18] [19] several influential commentaries reacted by calling for an abolition of the prosthesis. [20] [21] Understanding the effect that different types of primary total hip replacements-especially metal-on-metal hip resurfacing-have on long term mortality is an essential part of treating patients with debilitating osteoarthritis. The establishment of national databases has allowed the analysis of population based mortality in the long term.…”

Section: Introductionmentioning

confidence: 99%

Mortality rates at 10 years after metal-on-metal hip resurfacing compared with total hip replacement in England: retrospective cohort analysis of hospital episode statistics

Kendal

Prieto-Alhambra

Arden

et al. 2013

BMJ

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Objectives To compare 10 year mortality rates among patients undergoing metal-on-metal hip resurfacing and total hip replacement in England.Design Retrospective cohort study.Setting English hospital episode statistics database linked to mortality records from the Office for National Statistics.Population All adults who underwent primary elective hip replacement for osteoarthritis from April 1999 to March 2012. The exposure of interest was prosthesis type: cemented total hip replacement, uncemented total hip replacement, and metal-on-metal hip resurfacing. Confounding variables included age, sex, Charlson comorbidity index, rurality, area deprivation, surgical volume, and year of operation.Main outcome measures All cause mortality. Propensity score matching was used to minimise confounding by indication. Kaplan-Meier plots estimated the probability of survival up to 10 years after surgery. Multilevel Cox regression modelling, stratified on matched sets, described the association between prosthesis type and time to death, accounting for variation across hospital trusts.Results 7437 patients undergoing metal-on-metal hip resurfacing were matched to 22 311 undergoing cemented total hip replacement; 8101 patients undergoing metal-on-metal hip resurfacing were matched to 24 303 undergoing uncemented total hip replacement. 10 year rates of cumulative mortality were 271 (3.6%) for metal-on-metal hip resurfacing versus 1363 (6.1%) for cemented total hip replacement, and 239 (3.0%) for metal-on-metal hip resurfacing versus 999 (4.1%) for uncemented total hip replacement. Patients undergoing metal-on-metal hip resurfacing had an increased survival probability (hazard ratio 0.51 (95% confidence interval 0.45 to 0.59) for cemented hip replacement; 0.55 (0.47 to 0.65) for uncemented hip replacement). There was no evidence for an interaction with age or sex.Conclusions Patients with hip osteoarthritis undergoing metal-on-metal hip resurfacing have reduced mortality in the long term compared with those undergoing cemented or uncemented total hip replacement. This difference persisted after extensive adjustment for confounding factors available in our data. The study results can be applied to matched populations, which exclude patients who are very old and have had complex total hip replacements. Although residual confounding is possible, the observed effect size is large. These findings require validation in external cohorts and randomised clinical trials. IntroductionTotal hip replacement was introduced in the 1960s and has developed into one of the most successful treatments in modern medicine. [1] [2] Historically, the operation involves replacingCorrespondence to: A Carr andrew.carr@ndorms.ox.ac.uk Extra material supplied by the author (see

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Section: Introductionmentioning

confidence: 99%

Mortality rates at 10 years after metal-on-metal hip resurfacing compared with total hip replacement in England: retrospective cohort analysis of hospital episode statistics

Kendal

Prieto-Alhambra

Arden

et al. 2013

BMJ

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“…17 Nor did the MHRA require companies to start proper post-approval studies. Although epidemiological studies have not found a link with cancer, 18 they may not reflect the current reality. The metal hips currently being implanted are different in design to earlier models on which the studies were based, and since metal on metal has primarily been used in younger people, patient demographics have also changed.…”

Section: Metal Ions and Genotoxicitymentioning

confidence: 95%

How safe are metal-on-metal hip implants?

Cohen¹

2012

BMJ

142

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Cohen examines the evidence of risk from metal-on-metal hips, the manufacturers' inadequate response, and how the regulatory bodies failed to give doctors and patients the information they need to make informed decisions Deborah Cohen investigations editor BMJ, London WC1H 9JRHundreds of thousands of patients around the world may have been exposed to toxic substances after being implanted with poorly regulated and potentially dangerous hip devices, a BMJ/ BBC Newsnight investigation reveals this week. Despite the fact that these risks have been known and well documented for decades, patients have been kept in the dark about their participation in what has effectively been a large uncontrolled experiment.This isn't the unlucky failure to spot the misdemeanours of one rogue company or the occasional unforeseen breakdown of a small number of devices. It is the inability to prevent a whole class of failing hip implant from being used in hundreds of thousands of people globally-a class of implant that the usually reticent National Joint Registry of England and Wales described recently as a "cause for concern." 1 2 The implants concerned are "metal on metal"-the head at the top and the lining of the cup it fits into are made of cobalt-chromium alloy rather than ceramic or polyethylene-and there are models for both total hip replacement and hip resurfacing.From their arrival on the orthopaedic scene in 1997, they were marketed as the latest advance in hip replacement and were targeted at young active patients who needed a hip that would last a whole lifetime. And while there is evidence that hip resurfacing works well in young active men, 3 the failure rates of resurfacing in women and of metal-on-metal total hip replacements in both sexes are higher than they should be. Average failure rates at seven years are 11.8% for resurfacing and 13.6% for metal-on-metal total hip replacement, although failure rates vary with the brand used. This compares with rates of 3.3%-4.9% for hip implants made of other materials. Metal-on-metal devices have been implanted into over 60 000 patients in England and Wales since 2003-when the National Joint Registry first began to record procedures. Before this date numbers are unreliable. In the US the figure is closer to a million and likely to increase. At the annual American Academy of Orthopedic Surgeons conference in February this year, a roll call of manufacturers was still promoting these products to the 40 000 attendees in the exhibitor hall.Cobalt-chromium implants have been used successfully in orthopaedics for years-for example, in knee operations and fracture repair. They are known to release metal ions, but some metal-on-metal prostheses do so on a much greater scale than previously thought. These ions can seep into local tissue causing reactions that destroy muscle and bone and leaving some patients with long term disability. 4 Local tissue reactions associated with ions from metal-on-metal hips were first described in detail as long ago as 1975. 5 The ions can also leach into t...

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“…[50][51][52][53][54][55][56][57][58][59] However, complications particular to this procedure have been identified (as stated previously), and emphasis is placed on patient selection, component selection and surgical technique to avoid poor and adverse outcomes and short-term failures. 44,47,[60][61][62][63][64][65][66][67][68][69][70] Many surgeons avoid resurfacing in postmenopausal women because of an increased risk of femoral neck fracture, and in those with known renal insufficiency owing to the potential for metal ion accumulation.…”

Section: Obesitymentioning

confidence: 99%

Surgical management of hip osteoarthritis

Gandhi

Perruccio

Mahomed

2013

CMAJ

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Review CMAJ• Total hip replacement with a metal-on-polyethylene bearing surface remains the gold standard for the treatment of end-stage hip osteoarthritis, providing reliable improvement in pain and function with consistent implant longevity.• Registry reports suggest an increased rate of revision for hip resurfacing compared with total hip replacement, particularly among female patients.• A further registry report showed an increased failure rate of metal-onmetal bearing surfaces compared with ceramic and polyethylene at 7 years.• The outcomes of revision total hip replacement are poorer than those of primary replacement, with patients reporting worse pain and poorer function at 5 years after revision surgery.

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Ongoing problems with metal-on-metal hip implants

Cited by 52 publications

References 22 publications

Mortality rates at 10 years after metal-on-metal hip resurfacing compared with total hip replacement in England: retrospective cohort analysis of hospital episode statistics

Mortality rates at 10 years after metal-on-metal hip resurfacing compared with total hip replacement in England: retrospective cohort analysis of hospital episode statistics

How safe are metal-on-metal hip implants?

Surgical management of hip osteoarthritis

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