Abstract
Background
Evidence from recent trials has supported the efficacy of periarticular analgesic injection for pain control following total knee arthroplasty (TKA). However, no randomized controlled trial has compared the efficacy of periarticular analgesic injection with that of other regimens for simultaneous bilateral TKA.
Methods
We conducted a randomized controlled trial in which patients scheduled for simultaneous bilateral TKA were randomly assigned to receive periarticular analgesic injection or epidural analgesia. In the periarticular analgesic injection group, the injection contained 7.5 mg/ml ropivacaine 40 ml, 10 mg/ml morphine hydrochloride hydrate 1.0 ml, 1.0 mg/ml epinephrine 0.6 ml, methylprednisolone 80 mg, and ketoprofen 50 mg. These agents were mixed with normal saline to a combined volume of 120 ml. The 60 ml of the cocktail was injected into each knee. In the epidural analgesia group, the catheter was placed at the L2–3 or L3–4 level, and connected to an infusion pump delivering continuous infusion (flow rate: 4 ml/h) of 100 ml of 2 mg/ml ropivacaine plus 1.0 ml of 10 mg/ml morphine hydrochloride hydrate. Surgery was managed under spinal anaesthesia. Surgical techniques and postoperative medication protocols were identical in both groups. The primary endpoint was postoperative pain at rest, quantified as the area under the curve (AUC) of the score on a visual analogue scale.
Results
Seventy-one patients with 142 knees were randomly assigned to receive periarticular analgesic injection or epidural analgesia. The flow chart presented in Figure 1 outlines the trial. The periarticular analgesic injection group had a significantly lower AUC at 4–24 hour compared with the epidural analgesia group (174.9 ± 181.5 versus 360.4 ± 360.6; p = 0.0073), while no difference in the AUC was noted at 24–72 hour (1388.1 ± 727.2 versus 1467.3 ± 810.1; p = 0.67). The consumption of diclofenac sodium suppositories as rescue analgesia was significantly lower in the periarticular analgesic injection group than in the epidural analgesia group on the night of surgery (0.16 ± 0.4 versus 0.70 ± 0.9; p = 0.0013). The incidence of nausea on the night of surgery and postoperative day 1 and that of pruritus were significantly lower in the periarticular analgesic injection group than in the epidural analgesia group (7.4 % versus 45.5 %; p = 0.0031, 7.4 % versus 54.5 %; P = 0.0003, and 0 % versus 15.2 %; p = 0.014, respectively).
Conclusions
Compared with epidural analgesia, periarticular analgesic injection following simultaneous bilateral TKA was associated with better postoperative pain relief and decreased opioid-related side-effects. Periarticular analgesic injection is preferable to epidural analgesia for postoperative pain relief after simultaneous bilateral TKA.
