I was indexing a PT journal (that is what I do for a living) and came across an ad for this product. It is a gel pack that you can freeze or heat in the microwave that fits into a sleeve that will wrap around the knee. Sounds like it good be a good choice if you need to ice at work, in the car or if you don't use an ice machine.
https://www.torexhealth.com/
Simon
https://www.torexhealth.com/
Simon