Intra-articular Ropivacaine versus Extra-Capsular Ropivacaine in the Management of Immediate Postoperative Pain Following Knee Arthroscopy: A Prospective, Double-Blinded, Randomized Controlled Trial

Background: Acute postoperative pain management following knee arthroscopy continues to be a controversial and unresolved issue. Our objective was to compare the efficacy of intra-articular Ropivacaine and extra-capsular Ropivacaine in patients undergoing knee arthroscopy.

Methods: In this prospective, double-blinded, randomized controlled study we evaluated 35 patients who underwent knee arthroscopy in our institution between 2014-2018. Patients were randomized to receive either 10cc intra-articular Ropivacaine and 10cc extra-capsular saline, or vice versa. Sixteen patients received 10cc intra-articular Ropivacaine and nineteen patients received 10cc extra-capsular Ropivacaine. We recorded patient Visual Analog Scale (VAS) and analgesics intake every six hours on postoperative days (POD) 0, 1 and 2.

Results: Average VAS on POD0, POD1, POD2 and overall for the intra-articular Ropivacaine group were 2, 1.6, 0.9 and 1.5, respectively. Average VAS scores for the extra-capsular Ropivacaine group were 2.8, 2.7, 1.7 and 2.4, respectively. VAS scores and analgesics intake on POD0 did not significantly differ between the groups (p value=0.14 and 0.35, respectively). Intra-articular Ropivacaine was associated with lower VAS scores on POD1, POD2 and overall (p value=0.026, 0.09 and 0.002, respectively). Analgesics intake was also lower in the intra-articular Ropivacaine group on POD1, POD2 and overall (p value=0.05, 0.029 and 0.004, respectively).

Conclusions: Intra-articular Ropivacaine is associated with lower postoperative pain and analgesics intake in patients undergoing knee arthroscopy. We believe intra-articular Ropivacaine’s superiority in sustaining longer pain relief should be weighed against the possible mild risk for chondrotoxicity.