Can cryotherapy remove keloids on the knees?

That really depends on what sort of lasers/skin treatments you are doing. Ablative lasers, deep chemical peels or skin devices like fractional RF breach the skin layer and pose a risk for keloid formation. This is why I personally have both ablative and non-ablative fractional lasers for scar/rejuvenation/wrinkle treatments. If you are only using non-ablative lasers or laser toning, there is negligible risk. In fact, some non-ablative lasers like the pulsed-dye or long pulsed ND:Yag lasers can be useful for treating keloids!

Thanks for the question. I do agree with the answers posted by Dr Winston and Dr Ethan that intra-lesional steroid injections (injecting directly into the keloid) would be the most suitable treatment to reduce the size and thickness of the keloid. Several monthly injections will be needed. The initial injections may be a little more painful but the pain is usually better with subsequent injections. There will be some pain with the injection but this is usually bearable. If you are really afraid of the pain, applying some numbing cream prior to the injection may help.