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Having multiple long-term conditions should not prevent people with osteoarthritis having hip replacements. New research found that the surgery improved their quality of life and complication rates were generally low. Despite this, the study found that fewer than half of those with hip osteoarthritis had hip replacement surgery.

Osteoarthritis is a common type of arthritis that causes pain and stiffness. In severe cases, hip replacement surgery is recommended. However, surgery might be delayed, or even ruled out, if the person has other existing health conditions. Such decisions are not based on evidence; the researchers say no previous research has explored whether people with multiple long-term conditions have worse outcomes than others after this procedure.

This study analysed the health records of 27,560 people aged 65 and over, who all had a diagnosis of hip osteoarthritis. Decisions on surgery were influenced by long-term conditions, the study found; the more long-term conditions people had, the less likely they were to have a hip replacement. Yet these people generally had good outcomes and benefitted from surgery.

The research highlights the importance of an evidence-based approach. The researchers hope their work will help inform doctors and patients about the relative risks and benefits of hip replacement surgery.

Further information on hip replacements is available on the NHS website.

What’s the issue?

People with osteoarthritis have joints that are painful, stiff, and sometimes swollen. This happens when the protective cartilage on the ends of bones breaks down. It most often affects the knees, hips and small joints of the hands and is the most common type of arthritis in the UK.

When symptoms are mild, they can be managed with regular exercise, weight management or with special devices to reduce the strain on joints during everyday activities. If symptoms get worse, people may need painkillers or a structured exercise plan with a physiotherapist.

In severe osteoarthritis, people can have surgery to completely replace the hip or other affected joint. Hip replacement surgery generally gives people a greater range of movement and reduces their pain.

People having hip replacements are 70 years old, on average. By this age, many have other long-term conditions, such as high blood pressure or diabetes, which might increase the risk of any surgery. Doctors may therefore be concerned about recommending hip replacement surgery for older people who have such conditions.

Researchers explored how multiple long-term conditions influence the likelihood and timing of hip-replacement surgery. They also looked at the impact of multiple long-term conditions on the outcomes of hip replacement surgery.

What’s new?

The researchers analysed GP health records from across the UK. They included data from 27,560 people aged 65 years and older. Participants had an average age of 75 years and most (62%) were women. All had a diagnosis of hip osteoarthritis in their records.

The team assessed participants' general health through the number of other conditions, and medications mentioned in their records, and the number of primary care consultations in the preceding 12 months. There is no single way to measure other conditions; the researchers assessed conditions using different approaches, including a measure of frailty.

Hospital records showed that fewer than half (40%) the participants underwent hip replacement surgery.

In the whole group, which included people with and without multiple long-term conditions, the study found:

  • people with more long-term conditions were less likely to have hip replacement surgery, even if they had moderate poor health, and the benefits of surgery outweighed the risks
  • neither age nor gender affected the rate of surgery, which suggested that surgery was withheld because of the long-term conditions the people had, and not these other factors
  • even people who were ‘mildly frail’ were less likely to have the surgery
  • most surgery took place 10 months after a diagnosis was added to GP records, but the more pre-existing long-term conditions a person had, the longer they waited.

In a group of 6682 people with hip osteoarthritis and multiple long-term conditions, the researchers looked at the outcomes of hip replacement surgery.

They found that:

  • regardless of pre-existing conditions, patients reported improved quality of life 6 months after surgery
  • other conditions weakly predicted risk of complications (such as a heart attack or wound infection) but the increases in risk were small
  • people with worse health before surgery were more likely to have complications afterwards, though the complication rates (3%) and death rates (1%) were low
  • people’s health before surgery did not influence how long they stayed in hospital; but those with worse health before surgery were twice as likely to be readmitted to hospital afterwards than the healthiest people in the study group.

The researchers concluded that, for most people, having multiple long-term conditions should not be a barrier to having hip-replacement surgery.

Why is this important?

Professionals and patients both raise concerns about hip-replacement surgery when people have other long-term conditions. This research provides evidence about the risks and benefits of hip-replacement surgery for this group of people.

It found that hip-replacement surgery improves quality of life regardless of someone’s other conditions. The surgery could improve some other conditions, such as depression, because of the improvement in pain. The team would like to follow people up for longer, to understand the longer-term impact of surgery in people with multiple long-term conditions.

The findings from this study show that healthcare professionals and patients should decide together on the benefits of surgery to them. They should discuss the risks, including of anaesthesia, and jointly come to a decision based on evidence.

The researchers say that, as long as the risk of having a general anaesthetic is not too high, having multiple long-term conditions should not be a barrier to hip surgery.

What’s next?

These results depend on the accuracy of primary care health records. If a diagnosis was included in the medical records some time after the first symptoms appeared, people may have been suffering with pain for longer than the records suggest.

People with multiple long-term conditions did not stay in hospital any longer than other people after surgery. It is possible that the length of stay could be influenced more by type of procedure. Surgery carried out under local anaesthetic might have shorter hospital stays than those carried out under general anaesthetic.

You may be interested to read

One of the papers this NIHR Alert is based on: Ferguson R, and others. Influence of pre-existing multimorbidity on receiving a hip arthroplasty: cohort study of 28 025 elderly subjects from UK primary care. BMJ Open 2021;11:e046713

Another paper this NIHR Alert is based on: Ferguson R, and others. Does pre-existing morbidity influences risks and benefits of total hip replacement for osteoarthritis: a prospective study of 6682 patients from linked national datasets in England. BMJ Open 2021;11:e046712


Funding: This study was funded by the NIHR Research for Patient Benefit programme.

Conflicts of Interest: The study authors declare no conflicts of interest.

Disclaimer: NIHR Alerts are not a substitute for professional medical advice. They provide information about research which is funded or supported by the NIHR. Please note that views expressed in NIHR Alerts are those of the author(s) and reviewer(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.

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