The Impact of Epinephrine in the Periarticular Injection Cocktail using Ropivacaine for Total Knee Arthroplasty: A Prospective, Randomized, Double-Blind Comparison Study.

BACKGROUND: Epinephrine is used in periarticular injection using ropivacaine to produce a synergistic effect when used with local anesthetic agents but the effect has not been proven yet. The purpose of this study is to evaluate how effective epinephrine is on postoperative clinical outcomes in primary total knee arthroplasty (TKA). METHODS: One hundred sixteen cases (89 patients) who underwent primary TKA were randomized into 2 groups depending on whether epinephrine was mixed. Immediately after the operation, patient-controlled analgesia using fentanyl was initiated. The Numerical Rating Scale, the cumulative dose of fentanyl, active range of motion of the knee joint, and wound complications were evaluated postoperatively. RESULTS: There were no significant differences in mean postoperative Numerical Rating Scale, cumulative dose of fentanyl, and active range of motion between the 2 groups. Neither skin necrosis nor wound dehiscence requiring operative management for skin care was required in either group. CONCLUSION: The use of epinephrine in periarticular injection using ropivacaine after TKA did not have any effect on postoperative acute pain control and opioid usage. THE LEVEL OF EVIDENCE: Therapeutic level I.