title: Postoperative analgesia in TKA: ropivacaine continuous intraarticular infusion.
abstract: BACKGROUND
  Postoperative pain control is a challenge in patients undergoing TKA due to side effects and technical limitations of current analgesic approaches. Local anesthetic infiltration through continuous infusion pumps has been shown to reduce postoperative pain in previous studies.
  
  
  OBJECTIVE
  We assessed the effectiveness of intraarticular ropivacaine infusions in reducing pain and postoperative opioid use after TKA and determined whether such infusions accelerate functional recovery of the patient and reduce length of hospital stay.
  
  
  METHODS
  In a randomized, prospective, double-blind study, two groups were assigned: Group A (n = 25) underwent continuous intraarticular infusion with 300 mL ropivacaine 0.2% at a speed of 5 mL/hour through an elastomeric infusion pump and Group B (n = 25) had an elastomeric pump insertion with 300 mL saline solution at an infusion speed of 5 mL/hour. All patients had the same prosthesis model implanted. Parameters analyzed over the first 3 days, at discharge, and 1 month later included postoperative pain, joint function, opioid use, and length of hospital stay.
  
  
  RESULTS
  All patients in Group A showed a decrease in pain intensity measured by a visual analog scale and opioid use in the first 3 days. Mean length of hospital stay was also reduced in Group A (5.72 days) compared to Group B (7.32 days). There were no device-related complications.
  
  
  CONCLUSIONS
  Use of an infusion pump is effective in treating pain after TKA, reducing postoperative pain and opioid use. It also improves immediate functionality and patient comfort, reducing the mean length of hospital stay, without increasing the risk of complications.
  
  
  METHODS
  Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
authors.affiliation: Knee Division, Department of Orthopedics, La Paz University Hospital, Madrid, Spain. gcarderop@hotmail.com
authors.forename: Primitivo
authors.initials: P
authors.lastname: Gómez-Cardero
authors.forename: E Carlos
authors.initials: EC
authors.lastname: Rodríguez-Merchán
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000577:Amides / Q000008:administration & dosage*; D000698:Analgesia / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D018771:Arthralgia / Q000188:drug therapy* / Q000503:physiopathology; D019645:Arthroplasty, Replacement, Knee; D004311:Double-Blind Method; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007263:Infusions, Parenteral / Q000295:instrumentation; D007719:Knee Joint / Q000502:physiology; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D010149:Postoperative Pain / Q000188:drug therapy* / Q000503:physiopathology; D011182:Postoperative Care / Q000379:methods; D011446:Prospective Studies; D020127:Recovery of Function / Q000187:drug effects; D000077212:Ropivacaine; D016896:Treatment Outcome
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine