Analgesic effect of intra-articularly administered morphine, dexmedetomidine, or a morphine-dexmedetomidine combination immediately following stifle joint surgery in dogs.
OBJECTIVE
To compare the analgesic effects of intra-articularly administered saline (0.9% NaCl) solution, morphine, dexmedetomidine, and a morphine-dexmedetomidine combination in dogs undergoing stifle joint surgery for cranial cruciate ligament rupture.


METHODS
Randomized, controlled, clinical trial.


METHODS
44 dogs with cranial cruciate ligament rupture that underwent tibial tuberosity advancement (TTA) or tibial plateau leveling osteotomy (TPLO).


METHODS
Dogs received intra-articular injections of saline solution (0.2 mL/kg [0.09 mL/lb]), morphine (0.1 mg/kg [0.045 mg/lb]), dexmedetomidine (2.5 μg/kg [1.14 μg/lb]), or a combination of morphine (0.1 mg/kg) and dexmedetomidine (2.5 μg/kg). Intra-articular injections of the stifle joint were performed after completion of the corrective osteotomy procedure, just prior to skin closure. Signs of pain were assessed every 2 hours thereafter on the basis of mean behavioral and objective pain scores. Dogs with pain scores exceeding predetermined thresholds were given hydromorphone (0.05 mg/kg [0.023 mg/lb], SC) as rescue analgesia.


RESULTS
Time to rescue analgesia did not significantly differ between dogs that underwent TTA versus TPLO. No significant difference in time to rescue analgesia was found among dogs receiving intra-articular injections of dexmedetomidine (median, 6 hours; range, 2 to 10 hours), morphine (median, 7 hours; range, 4 to 10 hours), or saline solution (median, 5 hours; range, 4 to 10 hours). However, time to rescue analgesia for dogs receiving intra-articular injection of the morphine-dexmedetomidine combination (median, 10 hours; range, 6 to 14 hours) was significantly longer than the time to rescue analgesia for other treatment groups.


CONCLUSIONS
Intra-articular administration of the morphine-dexmedetomidine combination provided longer-lasting postoperative analgesia, compared with either morphine or dexmedetomidine alone, in dogs undergoing TTA or TPLO.
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.
Natalia
N
Soto
Amy E
AE
Fauber
Jeff C H
JC
Ko
George E
GE
Moore
Nicolaas E
NE
Lambrechts
D018712:Analgesics, Non-Narcotic / Q000627:therapeutic use; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000627:therapeutic use; D000818:Animals; D016118:Anterior Cruciate Ligament / Q000601:surgery; D020927:Dexmedetomidine / Q000008:administration & dosage / Q000627:therapeutic use*; D004283:Dog Diseases / Q000188:drug therapy* / Q000601:surgery; D004285:Dogs; D004359:Drug Therapy, Combination; D007270:Injections, Intra-Articular; D009020:Morphine / Q000008:administration & dosage / Q000627:therapeutic use*; D010149:Postoperative Pain / Q000517:prevention & control / Q000662:veterinary*; D012421:Rupture / Q000601:surgery / Q000662:veterinary; D013264:Stifle / Q000601:surgery*
D018712:Analgesics, Non-Narcotic; D000701:Analgesics, Opioid; D020927:Dexmedetomidine; D009020:Morphine