Comparison between ropivacaine local infiltration analgesia with ketorolac or placebo for total knee replacement surgery.

Background/aims Optimal pain treatment with minimal side-effects is essential for early mobilization and recovery in patients undergoing total knee replacement surgery. Local infiltration analgesia (LIA) with local anaesthetic might be effective and adjuncts such as ketorolac may provide additional effects on opioid requirements and pain. We tested the hypothesis that adding ketorolac significantly improves analgesia after total knee replacement surgery. Methods Sixty patients were enrolled in this prospective double-blinded study and allocated to either group R (placebo) or Group RK (ketorolac 120 mg). All patients received high-volume LIA with 150 ml ropivacaine (300 mg) with epinephrine added either placebo or ketorolac (30 mg) combined with eight 10 ml ropivacaine doses (100 mg) added either placebo or ketorolac (15 mg) administered every 6 h through an intra-articular catheter for 48 h. postoperatively. The primary outcome was patient-controlled morphine consumption from 0-6 and 0-48 h after surgery. Time to first rescue administration, pain intensity (0-100 mm visual analogue scale) at rest and during mobilization and side-effects were recorded until 96 h after surgery. Results Six and forty-eight morphine consumption was significantly reduced in group RK compared with group R. Time to first rescue analgesia was significantly prolonged with 4 h in group RK [median (IQR)] 490 min (248-617) compared with 223 min (115-319) group R (P < 0.02). Pain at rest and during movement was significantly reduced for 48 h with the addition of ketorolac. Length of hospital stay was reduced with one day in group RK [median (IQR)] 2 days (2-3) compared with group R3 days (2-3) (P =0.004). Conclusions Ketorolac resulted in a 75% reduction in 48 h postoperative morphine requirements. This was also significantly associated with prolonged analgesia, reduced pain intensity scores at rest and during movement and reduced length of hospital stay.