title: Chondrolysis after continuous intra-articular bupivacaine infusion: an experimental model investigating chondrotoxicity in the rabbit shoulder.
abstract: OBJECTIVE
  Postoperative pain pumps are increasingly used to deliver a continuous infusion of local anesthetic into the surgical wound or the joint. Recently, there have been concerns that the use of such devices may be associated with chondrotoxicity and even cases of chondrolysis in the shoulder. An experimental model is presented that investigates potential chondrotoxic effects of a continuous intra-articular infusion of bupivacaine in the rabbit shoulder.
  
  
  METHODS
  We divided 30 rabbits into 3 groups that received continuous infusions of either saline solution, bupivacaine, or bupivacaine with epinephrine into the glenohumeral joint over a period of 48 hours. Animals were killed after 1 week, and osteochondral and synovial samples from the glenohumeral joint underwent analyses with confocal microscopy for live/dead cell assay, metabolic sulfate uptake assessment, and conventional histologic analysis.
  
  
  RESULTS
  Infusion of bupivacaine with epinephrine and without epinephrine decreased sulfate uptake by 56% (P = .009) and 50% (P = .02), respectively, when compared with saline solution; cell viability decreased by 20% (P = .08) and 32% (P = .02), respectively. Histologic analysis yielded significantly worse scores for bupivacaine infusion with epinephrine (P = .004) and without epinephrine (P = .02). The results for bupivacaine with or without epinephrine were not significantly different.
  
  
  CONCLUSIONS
  Continuous intra-articular infusion of bupivacaine with and without epinephrine led to significant histopathologic and metabolic changes in articular cartilage.
  
  
  CONCLUSIONS
  Bupivacaine showed profound chondrotoxic effects in an experimental model that closely followed the current clinical application of postoperative pain pumps. The results caution against the use of such devices in applications for smaller joints with minimal clearance or dilution as a result of hematoma, where continuous exposure of cartilage to bupivacaine is expected.
authors.affiliation: Department of Orthopedic Surgery, Rush University Medical Center, Rush Medical College, Chicago, Illinois 60612, USA.
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Gomoll
authors.forename: Richard W
authors.initials: RW
authors.lastname: Kang
authors.forename: James M
authors.initials: JM
authors.lastname: Williams
authors.forename: Bernard R
authors.initials: BR
authors.lastname: Bach
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Cole
mesh_terms: D016058:Analgesia, Patient-Controlled / Q000009:adverse effects*; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000009:adverse effects*; D000818:Animals; D002045:Bupivacaine / Q000008:administration & dosage / Q000009:adverse effects*; D002357:Cartilage Diseases / Q000139:chemically induced*; D002358:Cartilage, Articular / Q000187:drug effects; D004195:Disease Models, Animal; D004338:Drug Combinations; D004837:Epinephrine / Q000008:administration & dosage; D007270:Injections, Intra-Articular; D010149:Postoperative Pain / Q000188:drug therapy; D011817:Rabbits; D012785:Shoulder Joint / Q000187:drug effects*; D013583:Synovial Membrane / Q000187:drug effects
chemical_list: D000779:Anesthetics, Local; D004338:Drug Combinations; D002045:Bupivacaine; D004837:Epinephrine