Introduction
Postoperative pain, arthroplasty
Postoperative pain after knee arthroscopy and arthroplasty is a main factor affecting the early postoperative joint mobility and rehabilitation of patients [Ropivacaine is a pure S (-) isomer named S-(-)-1-propyl-2′,6′-pipecoloxylidide hydrochloride monohydrate. It has a pKa of 8.07 in 0.1 M KCl solution, which is approximately the same as that of bupivacaine (8.1) and is similar to that of mepivacaine. However, ropivacaine has an intermediate degree of lipid solubility compared to bupivacaine and mepivacaine. Because of its physical and chemical properties, ropivacaine produces a marked difference in sensory and motor blockades [