Postoperative pain is one of the issues that concern most patients after total knee arthroplasty (TKA). Periarticular multimodal drug injection and single anesthetic agent injection have been shown to effectively reduce postoperative pain. The purpose of this study was to compare the efficacy between multimodal drug injection and single anesthetic drug injection in controlling pain after TKA using a double-blinded randomized controlled trial.
Sixty-four osteoarthritic patients who underwent primary TKA were randomized into two groups. The multimodal drug injection group (group M) received levobupivacaine 150 mg, ketorolac 30 mg and morphine 5 mg, while the single anesthetic drug injection group (group S) received only levobupivacaine 150 mg. The primary outcomes were pain level (VAS), quantity of opioid consumption (mg) and time to request the first dose of analgesic drug (min).
Multimodal drug injection provided lower pain level in the first 4 h after surgery (VAS rest: 30 vs 46, p = 0.02; VAS motion: 45 vs 66, p = 0.03). They consumed less morphine mostly in the first 8 h after surgery (5 vs 12 mg, p < 0.0001) and had approximately 2 h longer time to request the first dose of analgesic drug (254 vs 148 min, p = 0.02).
Multimodal drug injection decreases pain level, reduces morphine consumption in the early postoperative period and prolongs the analgesic effect compared to single anesthetic drug. One may consider using single anesthetic agent only in patients who have high risk of opioid or NSAIDs side effect.