Comparison of peripheral nerve block with periarticular injection analgesia after total knee arthroplasty: a randomized, controlled study.

BACKGROUND: Pain after total knee arthroplasty (TKA) is usually severe. Recently, the usefulness of local periarticular injection analgesia (PAI) and peripheral nerve block (PNB) has been reported. We report a prospective blinded randomized trial of PAI versus PNB in patients undergoing primary TKA, in accordance with the CONSORT statement 2010.

METHODS: A total of 210 patients undergoing TKA under spinal anesthesia were randomized to receive PNB group or PAI group. In the PNB group, femoral nerve block and sciatic nerve block were performed. In the PAI group, a special mixture containing ropivacaine, saline, epinephrine, morphine hydrochloride, and dexamethasone was injected into the periarticular soft tissue. Pain intensity at rest was assessed using a numerical rating scale (NRS: 0-10) after surgery. Use of a diclofenac sodium suppository (25mg) was allowed for all patients at any time after surgery, and the diclofenac sodium suppository usage was assessed. The NRS for patient satisfaction at 48 hours after surgery was examined.

RESULTS: The average NRS for pain at rest up to 48 hours after surgery was low in both groups. Within 48 hours after surgery, the diclofenac sodium suppository usage was similar in both groups. There were no significant differences in the NRS for patient satisfaction in both groups.

CONCLUSIONS: The analgesic effects of PAI and PNB are similar. PAI may be considered superior to PNB because it is easier to perform.

LEVEL OF EVIDENCE: Therapeutic Level 1.