Moderate evidence supports that cryotherapy devices after knee arthroplasty (KA) do not improve outcomes.

Rationale
The literature extraction and review revealed one high quality study, two moderate quality studies, and one low quality study. 

The high quality study (Ivey 1994) used a cryotherapy sleeve on all of the patients and randomized the target temperatures up to including 70°F.  There was no evidence for dose dependent differences in need for pain medication including the control of 70°F. There is some issue with this control, in that it does have a cooling effect. As the only high level study it falls to a moderate level of evidence for this guideline.

Of the two moderate quality studies that used cryotherapy, one (Holmström 2005) consisted of postoperative unicompartmental knees that were randomized between epidural anesthesia, cryotherapy, and a third arm that does not document the use of simple cold packs/ice. It reported less pain medication consumption in the two treatment arms.

The second of the moderate quality studies (Su 2012) compared cryotherapy/compression to cryotherapy alone, including the early post-discharge period, and showed no significant outcome differences other than less overall narcotics used over the broad period of the first two weeks and higher levels of patient satisfaction.  The study involved 11 sites and the patients could not be blinded to treatment.

One low quality study (Thienpoint, 2014) demonstrated less flexion in the cryotherapy group at an intermediate time period; this was attributed to the patient having less freedom to bend their knee while in the device.

The lack of dose effect in reducing narcotic consumption in the high level study contradicts the findings in the two relevant moderate level studies, both of which were not internally supported by significant differences in visual analogue pain scales. There were no other significant differences in other outcomes in the two relevant moderate studies. 
  1. Holmstrom,A., Härdin,B.C. Cryo/Cuff compared to epidural anesthesia after knee unicompartmental arthroplasty: a prospective, randomized and controlled study of 60 patients with a 6-week follow-up. The Journal of arthroplasty 2005; 0: 316-321
  2. Ivey,M., Johnston,R.V., Uchida,T. Cryotherapy for postoperative pain relief following knee arthroplasty. J Arthroplasty 1994/6; 3: 285-290
  3. Su,E.P., Perna,M., Boettner,F., Mayman,D.J., Gerlinger,T., Barsoum,W., Randolph,J., Lee,G. A prospective, multi-center, randomised trial to evaluate the efficacy of a cryopneumatic device on total knee arthroplasty recovery. J Bone Joint Surg Br 2012/11; 11: 153-156
  4. Thienpont,E. Does advanced cryotherapy reduce pain and narcotic consumption after knee arthroplasty?. Clin Orthop Relat Res 2014/11; 11: 3417-3423