Hypersensitivity to mechanical stimuli following surgery has been reported in patients who subsequently develop chronic pain after surgery. In animals, peripheral injury increases prostaglandin production in the spinal cord, and spinal cyclooxygenase inhibitors reduce hypersensitivity after injury. We therefore tested the hypothesis that spinal ketorolac reduces hypersensitivity and acute and chronic pain after hip arthroplasty ( www.clinicaltrials.gov NCT 00621530). Sixty-two patients undergoing total hip arthroplasty with spinal anesthesia were randomized to receive 13.5 mg hyperbaric bupivacaine with spinal saline or 13.5 mg hyperbaric bupivacaine with 2 mg preservative-free ketorolac. The primary outcome was area of hypersensitivity surrounding the wound 48 h after surgery, but this only occurred in 4 patients, precluding assessment of this outcome. The groups did not differ in acute pain, acute opioid use, or pain incidence or severity at 2 and 6 months after surgery. There were no serious adverse events. Our results suggest that a single spinal dose of ketorolac does not substantially reduce acute surgical pain and is thus unlikely to reduce the risk of persistent incisional pain.
Trial registration: ClinicalTrials.gov NCT00621530.