To document and compare preoperative and postoperative stance analysis measurements in animals with naturally occurring patellar luxation.
131 client-owned dogs surgically treated for naturally occurring unilateral or bilateral patella luxation between March 30, 2015, and February 12, 2020.
Weight bearing as a percent body weight on each limb was recorded with the use of a platform device for analyzing stance (PetSafe Stance Analyzer; LiteCure LLC, Companion Animal Health) preoperatively and postoperatively for all dogs. Signalment, limb affected, lameness grade, luxation direction, luxation grade, and surgical procedure were collected from patient records and assessed for the effects of these variables on weight bearing preoperatively or at the first or second postoperative recheck examination.
There were 61 males and 70 females, with a mean age and body weight of 4.62 years and 13.01 kg, included in the study. As age increased, body weight decreased in these dogs (P = .025). There was a statistically significant improvement in lameness after surgery (P = .008) at the second postoperative recheck examination. Lameness significantly decreased as postoperative time increased (P < .001, r = 0.503). As age increased, lameness at the initial visit decreased compared to younger dogs but not significantly (P = .062). There was no significant effect of preoperative luxation grade, luxation direction, surgical procedure, or sex when comparing initial lameness or lameness at recheck examination.
Surgical correction of patella luxation improves lameness as measured by postoperative stance analysis. Preoperative luxation grade or direction, surgical procedure performed, and sex of the animal did not significantly affect outcome in this group of dogs.
To determine perioperative analgesia associated with oral administration of a novel methadone-fluconazole-naltrexone formulation in dogs undergoing routine ovariohysterectomy.
43 healthy female dogs.
Dogs were randomly assigned to receive the methadone-fluconazole-naltrexone formulation at 1 of 2 dosages (0.5 mg/kg, 2.5 mg/kg, and 0.125 mg/kg, respectively, or 1.0 mg/kg, 5.0 mg/kg, and 0.25 mg/kg, respectively, PO, q 12 h, starting the evening before surgery; n = 15 each) or methadone alone (0.5 mg/kg, SC, q 4 h starting the morning of surgery; 13). Dogs were sedated with acepromazine, and anesthesia was induced with propofol and maintained with isoflurane. A standard ovariohysterectomy was performed by experienced surgeons. Sedation and pain severity (determined with the Glasgow Composite Pain Scale—short form [GCPS-SF]) were scored for 48 hours after surgery. Rescue analgesia was to be provided if the GCPS-SF score was > 6. Dogs also received carprofen starting the day after surgery.
None of the dogs required rescue analgesia. The highest recorded GCPS-SF score was 4. A significant difference in GCPS-SF score among groups was identified at 6:30 am the day after surgery, but not at any other time. The most common adverse effect was perioperative vomiting, which occurred in 11 of the 43 dogs.
CONCLUSIONS AND CLINICAL RELEVANCE
Oral administration of a methadone-fluconazole-naltrexone formulation at either of 2 dosages every 12 hours (3 total doses) was as effective as SC administration of methadone alone every 4 hours (4 total doses) in dogs undergoing routine ovariohysterectomy. Incorporation of naltrexone in the novel formulation may provide a deterrent to human opioid abuse or misuse.
To assess the pharmacokinetics, clinical efficacy, and adverse effects of injectable methadone with the pharmacokinetic enhancer fluconazole (methadone-fluconazole), compared with the standard formulation of injectable methadone, in dogs after ovariohysterectomy. We hypothesized that 2 doses of methadone-fluconazole would provide 24 hours of postoperative analgesia.
3 purpose-bred dogs (pharmacokinetic preliminary study) and 42 female dogs from local shelters (clinical trial) were included.
Pharmacokinetics were preliminarily determined. Clinical trial client-owned dogs were blocked by body weight into treatment groups: standard methadone group (methadone standard formulation, 0.5 mg/kg, SC, q 4 h; n = 20) or methadone-fluconazole group (0.5 mg/kg methadone with 2.5 mg/kg fluconazole, SC, repeated once at 6 h; n = 22). All dogs also received acepromazine, propofol, and isoflurane. Surgeries were performed by experienced surgeons, and dogs were monitored perioperatively using the Glasgow Composite Measure Pain Scale–Short Form (CMPS-SF) and sedation scales. Evaluators were masked to treatment.
Findings from pharmacokinetic preliminary studies supported that 2 doses of methadone-fluconazole provide 24 hours of drug exposure. The clinical trial had no significant differences in treatment failures or postoperative CMPS-SF scores between treatments. One dog (methadone-fluconazole group) had CMPS-SF > 6 and received rescue analgesia. All dogs had moderate sedation or less by 1 hour (methadone-fluconazole group) or 4 hours (standard methadone group) postoperatively. Sedation was completely resolved in all dogs the day after surgery.
Methadone-fluconazole with twice-daily administration was well tolerated and provided effective postoperative analgesia for dogs undergoing ovariohysterectomy. Clinical compliance and postoperative pain control may improve with an effective twice-daily formulation.