title: Does advanced cryotherapy reduce pain and narcotic consumption after knee arthroplasty?
abstract: BACKGROUND
  Cryotherapy has been used to enhance recovery after orthopaedic surgery. Several cooling devices are available but few can guarantee a fixed temperature during a prolonged time and therefore have been criticized. The arrival of new advanced cryotherapy devices made it possible to test the effect of prolonged cooling on rehabilitation after joint replacement.
  
  
  OBJECTIVE
  The hypotheses of this randomized controlled trial (RCT) were that advanced cryotherapy devices compared with cold packs result in (1) better postoperative pain control resulting in a lower consumption of narcotics; (2) better early ROM; and (3) less postoperative bleeding and swelling.
  
  
  METHODS
  A priori sample size calculation had determined that to detect a difference of 2 points on the VAS, a sample size of 50 subjects per group at followup would be required, given a study power of 80%. One hundred sixteen patients were included and randomly allocated to receive advanced cryotherapy (n=58) or use of cold packs (n=58). The primary outcomes for the study were to evaluate pain with the VAS and analgesics consumption. Secondary outcomes were postoperative ROM, swelling, and blood loss. One hundred (50 in each group) patients had complete data available for analysis.
  
  
  RESULTS
  No statistically significant differences in VAS, need for analgesics, nor in secondary outcomes were observed, except for substantially reduced flexion at 6 weeks in the advanced cryotherapy group (114° versus 120°).
  
  
  CONCLUSIONS
  Advanced cryotherapy with a continuous temperature for a prolonged period does not deliver expected results of superior early recovery after knee arthroplasty. Greater sample sizes are required to fully determine significant differences between the two techniques for these study parameters. Immobilization of the knee in extension during the prolonged cryotherapy session resulted in lower active flexion at 6 weeks after surgery for the advanced cryotherapy group. Advanced cryotherapy should not be used in fast track knee arthroplasty if the economic cost is higher than the price of cold packs or offers no other concomitant advantages.
  
  
  METHODS
  Level II, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.
authors: Cliniques Universitaires Saint Luc-UCL, Avenue Hippocrate 10, 1200, Brussels, Belgium, emmanuel.thienpont@uclouvain.be.
authors: Emmanuel
authors: E
authors: Thienpont
mesh_terms: D000368:Aged; D000700:Analgesics / Q000627:therapeutic use; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000534:rehabilitation*; D017679:Cryotherapy / Q000379:methods*; D004487:Edema / Q000209:etiology / Q000517:prevention & control; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D008297:Male; D009294:Narcotics / Q000627:therapeutic use; D010147:Pain Measurement; D010149:Postoperative Pain / Q000209:etiology / Q000534:rehabilitation*; D019106:Postoperative Hemorrhage / Q000209:etiology / Q000517:prevention & control; D016059:Range of Motion, Articular; D020127:Recovery of Function; D016896:Treatment Outcome
chemical_list: D000700:Analgesics; D009294:Narcotics