Extended "three-in-one" block after total knee arthroplasty: continuous versus patient-controlled techniques.

UNLABELLED

This prospective, randomized, double-blinded study assessed the efficacy of patient-controlled analgesia (PCA) techniques for extended "3-in-1" block after total knee arthroplasty. A total of 45 patients were divided into three groups of 15. Over 48 h, all patients received 0.125% bupivacaine with 1 microg/mL clonidine via a femoral nerve sheath catheter in the following manner: as a continuous infusion at 10 mL/h in Group 1; as a continuous infusion at 5 mL/h plus PCA boluses (2.5 mL/30 min) in Group 2; or as PCA boluses only (10 mL/60 min) in Group 3. Pain scores, sensory block, supplemental analgesia, bupivacaine consumption, side effects, and satisfaction scores were recorded. Pain scores and supplemental analgesia were comparable in the three groups. Bupivacaine consumption was significantly less in Groups 2 and 3 than in Group 1 (P < 0.01), and in Group 3 than in Group 2 (P < 0.01). Side effects and satisfaction were comparable in the three groups. We conclude that extended "3-in-1" block provides efficient pain relief after total knee arthroplasty and that, compared with a continuous infusion, PCA techniques reduce the local anesthetic consumption without compromise in patient satisfaction or visual analog scale scores. Of the two PCA techniques tested, PCA boluses (10-mL lockout; time, 60 min) of 0.125% bupivacaine with 1 microg/mL clonidine was associated with the smallest local anesthetic consumption, and is, therefore, the recommended extended "3-in-1" block technique.

IMPLICATIONS

We demonstrated that, after total knee arthroplasty, an extended "3-in-1" block consisting of patient-controlled analgesia boluses (10 mL/60 min) of 0.125% bupivacaine with 1 microg/mL clonidine provides efficient postoperative analgesia and significantly minimizes local anesthetic consumption.