title: Intra-articular anaesthesia mitigates established pain in experimental osteoarthritis: a preliminary study of gait impulse redistribution as a biomarker of analgesia pharmacodynamics.
abstract: OBJECTIVE
  Develop a sensitive, functional biomarker of persistent joint pain in a large animal model of experimental osteoarthritis. Evaluate Impulse Ratio as a measure of weight distribution among supporting limbs throughout the early natural history of osteoarthritis and with local anaesthesia and analgesia.
  
  
  METHODS
  The distribution of weight bearing in the trot of 11 skeletally-mature dogs was analyzed before and after unilateral surgical intervention (cranial cruciate transection or distal femoral focal impact). The short-term effects of two analgesic treatments (intra-articular lidocaine and intra-dermal meloxicam) were then evaluated as an index of pain relief based on the redistribution of weight-bearing impulse between normal and injured limbs.
  
  
  RESULTS
  Impulse Ratio was able to resolve weight redistribution between limbs in both long-term (weekly for over 400 days) and short-term (15 min intervals) joint evaluations. Joint pain relief from lidocaine administration could be reliably tracked over its brief acting time course. Meloxicam administration resulted in ambiguous results, where average weight bearing in the injured limb did not increase, but the variability of limb use changed transiently and reversibly.
  
  
  CONCLUSIONS
  Joint function and the role of persistent joint pain in the development of osteoarthritis can be investigated effectively and efficiently in a large animal model through the use of Impulse Ratio. Impulse Ratio can be a functionally relevant and sensitive biomarker of locomotion-related joint pain.
authors: Faculty of Veterinary Medicine, University of Calgary, McCaig Institute for Bone and Joint Health, Canada. jmatyas@ucalgary.ca
authors: J R
authors: JR
authors: Matyas
authors: A
authors: A
authors: Gutmann
authors: J
authors: J
authors: Randev
authors: M
authors: M
authors: Hurtig
authors: J E A
authors: JE
authors: Bertram
mesh_terms: D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D000070598:Anterior Cruciate Ligament Injuries; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D018771:Arthralgia / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D001169:Arthritis, Experimental / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D015415:Biomarkers; D004195:Disease Models, Animal; D004285:Dogs; D005260:Female; D005264:Femoral Fractures / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology; D005684:Gait / Q000187:drug effects* / Q000502:physiology; D007270:Injections, Intra-Articular; D007271:Injections, Intradermal; D008012:Lidocaine / Q000494:pharmacology*; D008297:Male; D000077239:Meloxicam; D020370:Osteoarthritis, Knee / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D010865:Pilot Projects; D013843:Thiazines / Q000494:pharmacology*; D013844:Thiazoles / Q000494:pharmacology*; D016474:Weight-Bearing / Q000502:physiology
chemical_list: D000779:Anesthetics, Local; D000894:Anti-Inflammatory Agents, Non-Steroidal; D015415:Biomarkers; D013843:Thiazines; D013844:Thiazoles; D008012:Lidocaine; D000077239:Meloxicam
keywords: Analgesia; Experimental OA; Functional biomarker; Impulse Ratio; Pain