Effect of perineural dexamethasone as an adjuvant to levobupivacaine in saphenous nerve block for knee arthroplasty

Background Total knee arthroplasty (TKA) is a major surgery where postoperative pain management not only aims for patients comfort but also is crucial to achieve post-operative ambulation leading to better outcome and preventing post-operative complications. Femoral nerve block is commonly used following Total knee arthroplasty for post-operative pain control but affects the quadriceps muscle strength increasing the risk of falls. Meanwhile, Adductor canal block has only sensory effect while preserving the motor power allowing for functional recovery within the first 24 hours post‑total knee arthroplasty. However, single injection nerve block is limited by its short duration. Adding adjuvants to the local anesthetic has shown prominent results in prolongation of the duration of the nerve block with dexamethasone being the most effective one. Aim of the Work to assess the efficacy of perineural dexamethasone as an adjuvant on duration of sensory blockage of Saphenous nerve block - performed by levobupivacaine -after knee arthroplasty surgery. Patients and Methods This randomized clinical trial study was carried at Ain Shams university hospitals, starting from March 2019 to August 2019. It included forty adult patients undergoing unilateral total knee arthroplasty who were randomly divided into 2 groups. A group received spinal anaesthesia followed by adductor canal block (ACB) with 19ml levobupivacaine plus 1ml normal saline and the other received spinal anesthesia followed by ACB with 19ml levobupivacaine injection plus 1ml (4mg) dexamethasone. The two groups were adequately monitored and assessed post-operatively for 24 hours and they were compared regarding analgesic outcome by recording time for first for analgesic need, total consumption of opioid and pain score during walking and climbing stairs. Side effects were also monitored and compared. Results prolongation of ACB when adding dexamethasone perineurally as an adjuvant to levobupivacaine, evident by prolongation of time for first analgesic requirement, decrease in total consumption of opioid in first 24 hours and lower pain score during walking and climbing stairs. Conclusion Adding dexamethasone as an adjuvant to ACB showed that it prolonged its duration with decrease in the post-operative pain scores and total morphine consumption.