This is a plain English summary of an original research article
Using a tourniquet in knee replacement surgery raises the risk of serious complications such as blood clots and infection. A new analysis of thousands of knee replacements also confirms that patients had more pain the day after surgery if a tourniquet was used.
Tying a tight band (tourniquet) around an injured arm or leg has been used for thousands of years to stem severe bleeding. Tourniquets are still routinely used in knee replacement surgery, but some experts argue that restricting blood flow in this way can cause clinical problems.
Serious complications are rare, with or without a tourniquet. But knee replacement surgery is a common procedure, performed more than 100,000 times each year in the UK. The study suggests that encouraging surgeons not to use tourniquets could avoid nearly 2,000 serious complications in the UK per year.
Surgeons should discuss the risks of using a tourniquet with patients before the surgery and offer a choice of using one or not, the researchers recommend.
What’s the issue?
People with severe arthritis of the knee may be offered knee replacement surgery, in which worn joints are replaced with versions made of metal and plastic. Most surgeons use a tourniquet during surgery. It inflates around the thigh to squeeze blood vessels closed; it reduces blood loss and keeps the surgical area drier.
Knee surgery usually takes about an hour. Some surgeons are concerned that restricting blood flow to the lower leg for that length of time may increase the risk of dangerous blood clots forming. These can travel around the body and block blood vessels beyond the leg, including in the lung.
Blood clots and other serious adverse effects following knee replacement surgery are rare. This means many surgeons who use a tourniquet will not see any problems, and may therefore not appreciate the risk. Before this study, there was little reliable evidence that pooled the results of multiple studies exploring this complication.
This review pooled the results of 41 high quality trials around the world. They all compared results of patients who were randomly chosen either to have a tourniquet or no tourniquet during knee replacement surgery. In all, 2,819 patients were included.
People who had a knee replacement with a tourniquet applied:
- had an increased risk of serious complications - from one in 34 (2.9%) without, to one in 17 (5.9%) with a tourniquet
- had a slight increase in pain on the day after surgery recorded by researchers (patients may not have noticed the difference)
- stayed in hospital eight hours longer on average
- had the same overall blood loss, knee function and health-related quality of life as when no tourniquet was used
- spent slightly less time in surgery (3.7 minutes on average), which was the only benefit of the tourniquet.
Overall, the study concluded that it is difficult to justify the use of a tourniquet in knee replacement surgery.
Why is this important?
Currently approximately nine in ten surgeons use a tourniquet during knee replacement surgery. This study shows that tourniquets increase the risk of blood clots, infections and other complications when used in knee surgery.
The risk is still low; the vast majority of knee replacement operations do not lead to serious complications. But because the procedure is common, the researchers estimate that changing surgical practice to avoid using tourniquets could avoid nearly 2,000 serious complications in the UK each year.
These results will raise awareness among surgeons of the possible negative effects of using a tourniquet. They could change practice and lead to more surgeons offering surgery without a tourniquet.
The study will also raise awareness among patients of the risks of using tourniquets. Patients will be able to discuss the issue with their surgeon.
You may be interested to read
The full paper: Ahmed I, and others. Tourniquet use for knee replacement surgery. Cochrane Database of Systematic Reviews 2020;2:CD012874
Abridged summary of the paper: Ahmed I, and others. Time to reconsider the routine use of tourniquets in total knee arthroplasty surgery. The Bone and Joint Journal 2021;103-B:5
Funding: This project was funded by a NIHR Post-Doctoral Fellowship Award.
Conflicts of Interest: The study authors declare no conflicts of interest.
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