Comparison of ultrasound-guided genicular nerve block and knee periarticular infiltration for postoperative pain and functional outcomes in knee arthroplasty – A randomised trial

BACKGROUND AND AIMS: Optimal analgesia after total knee arthroplasty (TKA) enhances patients’ and surgical outcomes. The study investigated the ultrasound-guided genicular nerve block versus the periarticular infiltration in TKA. METHODS: Eighty-eight patients aged above 50 years scheduled for unilateral TKA were randomised as: Group 1 received intraoperative periarticular infiltration (0.5 mL adrenaline [4.5 µg/mL], 20 mL bupivacaine 0.5% with 89.5 mL saline) and Group 2 received immediate postoperative genicular nerve block (15 mL bupivacaine 0.25% with 2.5 g/mL adrenaline). The postoperative morphine consumption was during the first two postoperative days the primary outcome. The secondary outcomes were time to rescue analgesia, pain scores and functional outcomes. The comparison between groups was performed using the Chi-square test, the Student's t-test and the Mann–Whitney U test, as appropriate. RESULTS: The postoperative morphine consumption during the first two postoperative days and pain scores at rest at 12 h postoperatively were less in Group 1 than in Group 2 (P < 0.001). Pain scores during movement on the first postoperative day were lower in the periarticular group than the genicular group at 6, 12 and 24 h (P < 0.001). At 18 h, pain scores were higher in the periarticular group than in the genicular group at rest and movement (P < 0.001). Quadriceps motor strength scores were comparable between groups (P > 0.05). The knee range of motion and time up and go test during both days showed a statistically significant difference in the periarticular group compared to the genicular group (P < 0.05). CONCLUSION: Periarticular infiltration and genicular nerve block yield effective postoperative analgesia and functional outcomes after TKA without motor affection.