Short answerIt may help a little in the first days, with less blood loss, pain and swelling and a better knee bend. The evidence is of low certainty.
Not enough evidence yet
What it is
Cold therapy, or cryotherapy, means cooling the skin around the knee with ice, cold water or a cooling device. It is used in the first hours and days after knee replacement.
What the research shows
pooled studies of cold therapy against placebo after knee replacement. It included 1,839 people aged 64 to 74, with most outcomes measured within 48 hours of surgery. Cold therapy may reduce blood loss, pain and swelling in the short term, and improve knee bend and function.
On average, the knee bent 8 degrees further at hospital discharge with cold therapy, 71 degrees against 63 degrees. Function was about 13 points better on a 100 point scale at two weeks, 89 against 75. The reviewers were unsure about side effects, because the evidence was very low certainty.
The studies were small, they differed in method, and the results varied between them. The evidence is current to May 2022.
Risks and effort
Follow the instructions from your hospital about how long and how often to use it.
What usually works instead
Cold therapy is an add-on to the usual care of pain relief, elevation and active exercise. See Does physiotherapy help after knee replacement? and Total Knee Replacement.
Questions people ask
How long should I use ice?
The review did not settle this. Follow the advice from your surgical team.
Does it reduce blood loss?
The review found that it may reduce blood loss, with low certainty. Ask your surgical team about blood loss in your case.
Is a cooling machine better than an ice pack?
The review combined many types of cold therapy and could not say.
Sources
Select a source to read what the study or guideline found, in plain words, with a link to the original.
Last reviewed 24 October 2026. Next review due October 2027.
