title: Doubtful effect of continuous intraarticular analgesia after total knee arthroplasty: a randomized double-blind study of 200 patients.
abstract: OBJECTIVE
  Local infiltration analgesia (LIA) is well established for effective postoperative pain relief in total knee arthroplasty (TKA). To prolong the effect of LIA, infusion pumps with local intraarticular analgesia can be used. We evaluated the effect of such an infusion pump for the first 48 h postoperatively regarding pain, knee function, length of stay (LOS) in hospital, and complications.
  
  
  METHODS
  200 patients received peroperative LIA and a continuous intraarticular elastomeric infusion pump set at 2 mL/h. The patients were randomized either to ropivacaine (7.5 mg/mL) or to NaCl (9 mg/mL) in the pump. Visual analog scale (VAS) pain (0-100 mm), analgesic consumption, side effects of medicine, range of motion (ROM), leg-raising ability, LOS, and complications during the first 3 months were recorded.
  
  
  RESULTS
  On the first postoperative day, the ropivacaine group had lower VAS pain (33 vs. 40 at 12 noon and 36 vs. 43 at 8 p.m.; p = 0.02 and 0.03, respectively), but after that all recorded variables were similar between the groups. During the first 3 months, the ropivacaine group had a greater number of superficial and deep surgical wound infections (11 patients vs. 2 patients, p = 0.02). There were no other statistically significant differences between the groups.
  
  
  CONCLUSIONS
  Continuous intraarticular analgesia (CIAA) with ropivacaine after TKA has no relevant clinical effect on VAS pain and does not affect LOS, analgesic consumption, ROM, or leg-raising ability. There may, however, be a higher risk of wound-healing complications including deep infections.
authors.affiliation: Department of Orthopedics , Skåne University Hospital, Clinical Sciences, Lund University, Lund , Sweden.
authors.forename: Abdulemir
authors.initials: A
authors.lastname: Ali
authors.forename: Martin
authors.initials: M
authors.lastname: Sundberg
authors.forename: Ulrik
authors.initials: U
authors.lastname: Hansson
authors.forename: Johan
authors.initials: J
authors.lastname: Malmvik
authors.forename: Gunnar
authors.initials: G
authors.lastname: Flivik
mesh_terms: D000368:Aged; D000577:Amides / Q000008:administration & dosage* / Q000627:therapeutic use*; D000698:Analgesia / Q000009:adverse effects / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000627:therapeutic use; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D015994:Incidence; D007260:Infusion Pumps; D007270:Injections, Intra-Articular; D007719:Knee Joint / Q000502:physiology / Q000601:surgery*; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D010149:Postoperative Pain / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control*; D016059:Range of Motion, Articular / Q000502:physiology; D012307:Risk Factors; D000077212:Ropivacaine; D012965:Sodium Chloride / Q000008:administration & dosage; D013530:Surgical Wound Infection / Q000453:epidemiology; D016896:Treatment Outcome
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D012965:Sodium Chloride; D000077212:Ropivacaine