Perioperative Pregabalin Reduces Neuropathic Pain at 3 Months after Total Knee Arthroplasty (TKA)
Asokumar Buvanendran, M.D., *Scott S. Reuben, MD, Maruti Kari, MD, Jeffrey S. Kroin, PhD, Craig Della Valle, MD, Rush University Medical Center, *Baystate Medical Center.
Introduction: Pregabalin has been shown to be effective for the treatment of chronic neuropathic pain (Pain Res Manag 2006; 11:16A-29A). Pregabalin administered before and after surgery reduced opioid use following spinal fusion surgery (Anesth Analg 2006;103:1271). This study examines the hypothesis that pregabalin administered perioperatively for patients’ undergoing total knee arthroplasty (TKA) can reduce chronic long-term pain syndromes.
Methods: Following IRB approval, a total of 146 patients having primary TKA were enrolled in this randomized, placebo-controlled, double-blind study. Patients were randomly assigned to 2 drug groups. Half of the patients received pregabalin 300 mg orally 2 hours prior to surgery, and the other half received matching placebo, at the same time point. In the operating room, patients were sedated with midazolam and a combined spinal-epidural procedure performed. At completion of surgery, epidural infusion of fentanyl/bupivacaine was initiated using continuous basal infusion with superimposed patient-controlled bolus. Patients subsequently received repeated doses of pregabalin 150 mg b.i.d. or placebo starting the day after surgery, with drug dosing continued up until day 14 post-surgery. The incidence of neuropathic pain was assessed 3 months post-surgery using the S-LANSS score, a valid diagnostic tool to assess neuropathic pain, with patients scoring ³12 considered to have neuropathic pain (J Pain 2005;6:149). The incidence of mechanical allodynia (stroking) or hyperalgesia (pressure) was also recorded. Comparison between the 2 groups was by chi-squared test.
Results: There was no difference in demographics (age, weight, etc.) between the 2 groups. At 3 months post-TKA, the incidence of patients with neuropathic pain post-TKA was lower in the pregabalin (1.49%) group compared to the placebo (11.39%) (P=0.018). The incidence of allodynia in the operated leg (fig) was also lower (P=0.0337) at 3 months for the pregabalin group (14%) than the placebo group (37%). The incidence of hyperalgesia in the operated leg was lower (P=0.0346) for the pregabalin group (20%) than the placebo group (34%). Patients who received pregabalin also had lower VAS pain scores in the operated leg at 3 months post-TKA compared to placebo (P=0.047).
Discussion: Perioperative administration of pregabalin decreased the incidence of neuropathic pain from 11.39% to 1.49% at 3 months after TKA. This suggests that pregabalin may be a useful perioperative medication for decreasing the incidence of chronic pain for patients undergoing this surgical procedure.
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