Local infiltration analgesia for total knee arthroplasty: should ketorolac be added?

BACKGROUND Adequate postoperative analgesia with minimal side-effects is essential for early mobilization and recovery in patients undergoing total knee arthroplasty (TKA). High-volume local infiltration analgesia (LIA) with ropivacaine has been introduced, but effects of adjuvants are still debated. We tested the hypothesis that the addition of ketorolac to LIA significantly improves analgesia after TKA. METHODS Sixty patients undergoing TKA were randomized to receive intraoperative LIA (ropivacaine 300 mg and epinephrine 0.5 mg) combined with either ketorolac 30 mg (ketorolac group) or saline (control group). After surgery, eight bolus doses of ropivacaine 100 mg combined with either ketorolac 15 mg (ketorolac group) or saline (control group) were administered every 6 h via an intra-articular catheter. The primary outcome was postoperative consumption of i.v. morphine patient-controlled analgesia (PCA). Secondary outcomes were time to first request of i.v. morphine PCA, pain intensity, side-effects, and readiness for hospital discharge. RESULTS Consumption of i.v. morphine PCA was lower in the ketorolac group vs control group {0-6 h: 0 (0-0) vs 5 (0-10) mg, P<0.0001; 0-48 h: 10 (0-22.5) vs 48.75 (30-82.5) mg, P<0.0001 [median (inter-quartile range, IQR)]}. Time to first request of i.v. morphine PCA was longer in the ketorolac group vs the control group [490 (248-617) vs 223 (115-319) min, P=0.02, median (IQR)]. Early postoperative pain (<48 h) and readiness for hospital discharge were also significantly reduced in the ketorolac group. CONCLUSIONS LIA with ketorolac results in reduced morphine consumption, reduced pain intensity, and earlier readiness for hospital discharge.