Evidence
Alert

More than 50% of hip replacements appear to last 25 years

Data from national registries and large case series show that in those countries, around 85% of total hip replacements last for 15 years, with 58% lasting for 25 years. This means that those hip replacements have lasted last longer than was first thought. It is good news for an ageing population, as it should mean that the chances of needing a second hip operation are reducing.

However, it is not clear how directly relevant the results of this study are to the UK. The NIHR-funded study didn’t include data from the National Joint Registry of England, Wales, Northern Ireland and the Isle of Man. And the hip replacement components that were used for patients in the study are not currently used in the UK, as techniques and parts have progressed over the last 25 years. Nevertheless, it is likely that despite these reservations, the average longevity of all the devices is getting better.

 

Why was this study needed?

Total hip replacement is a common surgical procedure, where a damaged hip joint is replaced with an artificial one. There are several components, which can be made of different materials, with various ways of fixing them in place.

In 2017 there were 96,717 primary procedures carried out in England, Wales and Northern Ireland. There were also 8,589 hip revision procedures. These are further operations, carried out when the artificial joint components wear out, loosen or break. Revision procedures may not be as effective at relieving pain and improving function, and often fail more quickly.

The average age of a patient receiving a replacement in the UK in 2017 was 69 years. Many people, when told they need a hip replacement, ask how long it will last. As average life expectancy increases, this question becomes more relevant. But there has been little good quality long-term evidence. This study aimed to fill that gap.

 

What did this study do?

This systematic review and meta-analysis included 44 case series that reported long-term outcomes of 13,212 hip replacement procedures. The authors also carried out a meta-analysis of data taken from the national joint replacement registries of Australia and Finland. These provided 215,676 procedures, with outcomes at 15, 20 and 25 years.

It isn’t clear how generalisable the results of this study are. Only the Finnish registry had follow-up data at 20 and 25 years, and the quality of the case series was generally low. Also, the study draws on historical data. The metal, ceramic and plastic components used in the underlying case series and registries are not all used in the UK currently.

 

What did it find?

Data from the case series was more prone to selection bias, but showed:

  • After 15 years 85.7% of hip replacements were intact (95% confidence interval [CI] 85.0 to 86.5; 12 case series, 5,792 hips).
  • After 20 years, 78.8% were intact (95% CI 77.8 to 79.9; 20 series, 7,192 hips).
  • After 25 years 77.6% were still intact (95% CI 76.0 to 79.2; 8 series, 4,617 hips).

Data from the registries had more patients followed up for longer and was less prone to selection bias. It showed a different pattern and was probably more reliable for estimating the long term outcomes than the case series:

  • After 15 years, 89.4% of hip replacements had survived (95% CI 89.2 to 89.6; 215,676 hips from both the Australian and Finnish registries).
  • After 20 years, 70.2% were intact (95% CI 69.7 to 70.7; 73,057 hips from the Finnish registry).
  • After 25 years, 57.9% were still intact (95% CI 57.1 to 58.7; 51,359 hips from the Finnish registry).

 

What does current guidance say on this issue?

NICE guidance published in 2014 recommends hip replacement as a treatment option for end-stage arthritis of the hip, but only if the component parts have rates (or projected rates) of revision of 5% or less at 10 years.

NICE doesn’t recommend a particular type of implant or component parts. It says that a patient’s age, activity levels, medical history and the surgeon’s preferences and experience of using a particular type of implant should be taken into consideration.

 

What are the implications?

The results from the registry data are likely to be more realistic and reliable than the case series data, due to the larger number of patients involved, and the lower risk of selection bias.

Using those figures, patients and surgeons can expect a hip replacement to last 25 years in more than half of all cases. Longer lasting components will reduce the need for hip revision procedures.

However, the implications of this study for UK practice are difficult to determine, given that UK data was not included. Long-term data of the hip replacement components commonly used in the UK is available from the UK National Joint Registry.

 

Citation and Funding

Evans JT, Evans JP, Walker R et al. How long does a hip replacement last? A systematic review and meta-analysis of case series and national registry reports with more than 15 years of follow-up. Lancet. 2019;393:647-54.

This study was supported by the NIHR Biomedical Research Centre at the University Hospitals Bristol NHS Foundation Trust and the University of Bristol.

 

Bibliography

National Joint Registry. Public and patient guide to the NJR’s 14th annual report 2017: hip replacement edition. London: National Joint Registry; 2018.

National Joint Registry. Types of primary hip replacements undertaken. London: National Joint Registry; 2018.

NHS website. Hip replacement. London: Department of Health and Social Care; 2016.

NICE. Total hip replacement and resurfacing arthroplasty for end-stage arthritis of the hip. TA304. London: National Institute for Health and Care Excellence; 2014.

Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre

 

Commentaries

Expert commentary

Hip replacement is a highly successful operation at improving pain and function. This study found that hip replacements last 25 years in 58% of patients. The results offer additional data to inform discussions regarding potential risks and benefits of joint replacement surgery.

It is still not possible to provide patient-specific estimations of implant survival. Patient factors are important; for example, younger patients are more likely to require revision surgery in the future. Furthermore, replacements may ‘fail’, with pain and functional limitation, but are not necessarily revised.

Long-term survival data are inherently historical, and the projected longevity of prostheses implanted today is not known. Continued evaluation of a range of outcomes is necessary to drive advances in this field.

 Antony Palmer, NIHR Academic Clinical Lecturer in Trauma and Orthopaedics, University of Oxford

The commentator declares no conflicting interests