What cryotherapy adds after knee replacement

A retrospective cohort study looked at 100 patients after primary knee arthroplasty and compared standard rehabilitation alone against standard rehabilitation plus cryotherapy. Outcomes ran from Hospital for Special Surgery (HSS) knee scores, range of motion and knee circumference through to pain, opioid use, length of stay and satisfaction.

One caveat up front, because it shapes how much weight to give this: patients were not randomised. They were sorted into the cryotherapy or control group by clinical practice patterns and patient preference, so the groups could differ in ways the study cannot fully account for.

In the first two weeks, the cryotherapy group did better on almost everything measured. At one week they had higher HSS scores, more knee flexion, less of an extension deficit and smaller knee circumference. Pain was lower at one and two weeks, opioid use in the first 48 hours was lower, and hospital stays were shorter. Satisfaction at six weeks was higher.

Then the gap closed. By six weeks, the between-group differences had disappeared on the functional measures. No difference in complications, and no cold-related adverse events.

So cryotherapy is a comfort measure for the early weeks, nothing more. In the first fortnight after a knee replacement, when pain and swelling are the main barriers to moving, adding cold looks like it helps patients hurt less, swell less, use fewer opioids and get moving sooner. Those are real wins for that window, and the opioid-sparing signal is worth having in the room.

What it does not appear to do is change patient outcomes by six weeks. So position it accordingly. Cryotherapy is reasonable as a comfort and swelling adjunct in early rehab, used to get a patient moving and onto their loading program faster. It is not something to sell as improving their final range or function, because this data does not show that, and the study design is not strong enough to claim it even if the numbers had held.

So tell them straight. The cold makes the first couple of weeks more comfortable and gets them moving sooner, and the moving is what actually gets them better.

Cryotherapy looks helpful for early comfort, swelling and opioid use after knee replacement, with no measurable functional edge by six weeks. Use it as a comfort adjunct, not a cure, and remember the data is non-randomised.

https://pubmed.ncbi.nlm.nih.gov/42251302/