This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.
Most people recover well after a hip replacement, but some will develop an infection. This can mean the artificial joint needs to be replaced in one- or 2-stage surgery. Research found that one-stage hip revisions were as effective as 2-stage procedures at relieving pain and improving hip stiffness and function. One-stage procedures were also better value for money.
Infection of an artificial joint is a rare but severe complication. People often need surgery to remove their artificial hip and the surrounding infected tissue. The 2-stage procedure allows surgeons to ensure, as far as possible, the infection is gone before they implant a new joint. But the replacement of the joint can be delayed for weeks or months. A newer, less common, one-stage procedure is also available.
Researchers compared people’s experiences of one- and 2-stage surgery to replace an artificial hip following infection. They found no differences between the procedures in people’s pain, function, or stiffness 18 months on. Analyses showed that one-stage procedures were associated with fewer complications; they were also cheaper to perform. The researchers recommend increased use of one-stage surgery wherever possible.
What’s the issue?
In the UK in 2019, more than 100,000 people had a first hip replacement. Many hip replacements last for over 25 years. However, of every 100 people who have a hip replacement, 1 - 2 develop an infection in the artificial joint within 2 years. Infection can cause severe pain or disability and people sometimes need further surgery.
In revision surgery, infected tissue surrounding the joint is removed, and the artificial joint replaced. Typically, this is carried out in 2 stages: infected tissue and all joint replacement implants are removed in the first stage, and, after the infection is completely cleared, a new artificial joint is inserted in the second stage. But people may wait weeks and sometimes months for the second stage. While they wait, their mobility and quality of life can be poor. In one-stage surgery, infected tissue and implants are removed, and the new joint inserted, in a single procedure.
Previous studies have shown that rates of reinfection are similar after one- and 2-stage hip revisions. However, few studies have explored people’s experiences of surgery (their pain, mobility, and how quickly they return to everyday activities).
In this study, researchers assessed how well people recovered from one- and 2-stage surgery to replace an artificial hip after infection. They also assessed value for money.
The study was carried out at 12 bone and joint specialist centres in the UK, and 3 in Sweden. It included 140 people requiring a surgery to replace an artificial hip after infection. 65 people were randomly assigned to one-stage, and 75 to 2-stage surgery. Their average age was 71; 1 in 3 (36%) were women.
After surgery, participants completed questionnaires about their experiences.
The study found that:
- 18 months after surgery, people’s pain, stiffness and function (ability to carry out everyday activities) were similar in the two groups
- 3 months after surgery, pain, stiffness and function were better after the one-stage procedure but from 6 months onwards, outcomes were similar
- few people (8%) in the single-stage group had a complication during surgery (such as fractures) compared to more (27%) in the 2-stage group.
There was no difference in infections after 18 months. The risk of being readmitted to hospital or needing further surgery was similar between the two groups.
One-stage operations were cheaper and offered better value for money. The one-stage group spent less time in hospital, had fewer visits to emergency departments, home visits from community nurses, and nights in residential care homes. This group had more appointments with primary care nurses. People also lost more working hours, but most in the study were older and not working and the study was not powered to explain this (secondary) finding.
Why is this important?
The study showed that one-stage revisions relieve pain, and improve stiffness and hip function, as effectively as two-stage procedures. One-stage revisions resulted in fewer complications during surgery, patients recovered more quickly, and it was more cost-effective.
People in the two-stage group required more support from district nurses and home care workers. The researchers say that people who had one-stage surgery were more able to self-care and to get out and about after surgery.
One-stage surgery is not always possible. Sometimes, during the procedure, it becomes clear that complex reconstruction is needed, which could require specialist or bespoke implants. The surgeon might decide to clear the infection in this first stage and return to carry out the reconstruction in a second stage, with the appropriate tools and implants.
It can also happen that a surgeon is unable to be sure that they have removed all infected or dead tissue in the first stage. In this case also, the surgeon might decide to delay the replacement of the joint.
What’s next for one-stage hip revisions ?
Surgeons could consider carrying out more one-stage hip revisions, the researchers say. They recommend the use of one-stage surgery whenever possible.
The study team are conducting an NIHR-funded study to explore how to integrate one-stage surgery into regular practice.
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This Alert is based on: Blom AW, and others. Clinical and cost effectiveness of single stage compared with two stage revision for hip prosthetic joint infection (INFORM): pragmatic, parallel group, open label, randomised controlled trial. British Medical Journal 2022;379:e071281.
A previous study by the same group on risk factors for infection of artificial joints: Blom AW, and others. Infection after total joint replacement of the hip and knee: research programme including the INFORM RCT. Programme Grants for Applied Research 2022; 10: 1-226.
A review on artificial joint infections: Tande AJ and Patel R. Prosthetic Joint Infection. Clinical Microbiology Reviews 2013; 27: 302–345.
Funding: This study was funded by an NIHR Programme Grant for Applied Research.
Conflicts of Interest: Several authors have received fees and funding from pharmaceutical companies and orthopaedic joint manufacturers. Full disclosure of the authors’ conflicts of interest can be found on the original paper.
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) at the time of publication. They do not necessarily reflect the views of the NHS, the NIHR or the Department of Health and Social Care.