The role of computer-assisted cryotherapy in the postoperative treatment after total knee arthroplasty: positive effects on pain and opioid consumption

Abstract

Purpose: The aim of this study was to investigate whether computer-assisted cryotherapy is effective in reducing postoperative pain and analgesics consumption, next to improving functional outcome and patient satisfaction after total knee arthroplasty (TKA). The hypothesis is that computer-assisted cryotherapy has positive effects on postoperative pain after TKA.

Methods: A single-centre non-blinded randomised controlled trial was designed to study the early (first postoperative week) and late (2 and 6 weeks postoperatively) additive effect of computer-assisted cooling after TKA. Participants scheduled for a TKA were randomly allocated to a cold (cryotherapy) C-group or a regular (control) R-group. Next to usual postoperative care for both groups, the C-group received computer-assisted cryotherapy during the first seven postoperative days. Primary outcome was pain, monitored with the numerical rating scale for pain and use of opioid escape medication. Secondary outcomes were function and swelling, monitored by active range of motion, timed up and go test and circumference measurements; patient-reported outcome measurements (KOOS and WORQ questionnaires); and patient satisfaction, monitored by the numerical rating scale for satisfaction.

Results: 102 patients participated in this study, both groups contained 51 patients. On most days during the first week, patients in the C-group scored significantly lower NRS pain scores and registered significantly less use of opioid escape medication. In a sub-analysis of 57 patients using the same standard pain protocol, patients in the C-group (n = 28) used less oxycodone during the first postoperative week. There were no significant differences between both groups in active range of motion, timed up and go, or circumference measurements. For the WORQ questionnaire, there was a significant difference between the two groups 6 weeks postoperatively in favour of the C-group. This could be however due to a reduced validity of this questionnaire shortly after TKA. The satisfaction score was not significantly different between both groups.

Conclusion: Computer-assisted cryotherapy following TKA can be beneficial during the first postoperative week in terms of pain reduction and diminished opioid consumption. No clear differences in knee function or swelling were seen.

Level of evidence: Therapeutic study with level of evidence I.

Keywords: Computer-assisted cryotherapy; Cooling; Knee function; Opioids; PROMs; Pain; Total knee arthroplasty; Total knee replacement.