CONTINUOUS EPIDURAL ANALGESIA VS USG GUIDED CONTINUOUS SAPHENOUS NERVE BLOCK IN UNILATERAL TKA

Abstract

Background: The main indication for TKA is to improve function, pain relieve and to increase quality of life in patients with degenerative knee joint disease. TKA is associated with severe postoperative pain and effective postoperative analgesia after TKA remains a challenge. Early mobilization is a challenge after TKA when a patient has severe pain and is receiving pain treatment. Despite a comprehensive multimodal analgesic regimen, TKA is often associated with intense postoperative pain. Epidural  analgesia being a viable alternative, however, faces a relatively high failure rate and may result in side effects such as urinary retention and motor block, with the latter potentially hindering mobilization. PNB with preserved muscle function and an adequate analgesic effect is desirable. Saphenous nerve block (SaphNB) blocks the largest sensory branch of the femoral nerve to the knee, the saphenous nerve, which is a component of the adductor canal. SaphNB thus provides analgesia with only sensory blockade and is as effective as FNB in reducing postoperative pain. This prospective study compared continuous Saphenous nerve block with continuous lumbar epidural block in patients undergoing total knee arthroplasty. This study assessed the efficacy of postoperative analgesia and rehabilitation scores of continuous epidural analgesia or continuous SaphNB after total knee arthroplasty.

Material and Methods: Patients received lumbar epidural or saphenous nerve block as a component of a multimodal analgesia. Quadriceps strength and pain score, rehabilitation scores, total bupivacaine consumption and rescue analgesic consumption was assessed in both groups preoperatively and at 6 to 8, 24, and 48h post anesthesia. Thirty patients received epidural analgesia (Group E), whereas 30 patients received continuous SaphNB(Group S). Pain scores were similar between the two groups. Difference in total bupivacaine consumption was insignificant among both the groups. One patient in Group E and 2 patients in Group S required for supplemental analgesics (p<0.05). Maximum knee flexion degrees were not different between the two groups. In this study, an effective pain control was obtained with both continuous epidural analgesia and SaphNB after total knee arthroplasty.

Conclusion: The authors hypothesized that SaphNB, compared with lumbar epidural block, would exhibit less quadriceps weakness and demonstrate noninferior pain score and opioid consumption at 6 to 48 h post anesthesia. Converting an established mode of pain therapy to a modified protocol may decrease incidence of adverse events rather than improve the quality of analgesia.

Key Words: Continuous Peripheral Nerve Blocks; Adductor canal block, Postoperative Analgesia; Epidural Analgesia, Knee Arthroplasty.