Comparison of Saphenous Nerve Block and Oral Oxycodone for Postoperative Pain Management in Total Knee Arthroplasty: A Randomized Clinical Trial

Background: Post-operative pain management following total knee replacement (TKA) is very crucial. There is a need to introduce some available, inexpensive, and effective methods for postoperative pain management. This randomized clinical trial was done for comparing the analgesic effect of an oral inexpensive drug (oxycodone) and saphenous nerve blocko study the better method for postoperative pain management after TKA surgery.Methods: This single-blind, randomized, controlled, single-center clinical trial was performed in Baghiatallah Hospital from June 2017 to June 2018. Eighty patients were included for TKA randomly divided into two groups. Group A received a single shot ultrasound-guided saphenous nerve block and group B had an oral intake of oxycodone started before and continued every 6 hours after surgery to control post-operative pain. The pain score by visual analog scale (VAS), nausea- vomiting and diclofenac consumption were assessed postoperatively at 2, 6, 12 and 24 hours post-spinal anesthesia administration. Data were analyzed by SPSS-21 and Chi2, Fishers' exact test, and Mann-Whitney were used for comparing data between the two groups. Result: The pain intensity according to the visual analog scale at 2, 6, 12, and 24 h post-operative was 1.25±1.37, 4.12±1.11, 5.25±0.89, and 4.57±095 in group A and 1.10±0.953.77±0.99, 4.05±0.78, and 2.95±0.78 in the group B respectively that was significantly lower in the group B at 12 and 24 hours (p <0.05). The mean diclofenac use was 87.01±68.02 mg in group B and 262.04±92.05 mg in the group A (p <0.001). Also, the incidence of nausea and vomiting was significantly higher in group B compared to the other group (p <0.001). Conclusion: Oral oxycodone can control post-operative pain better than saphenous nerve block in the management of postoperative relief and reducing total additional analgesic drugs consumption. But, adverse effects such as nausea and vomiting were lower in saphenous nerve block than oral oxycodone.