Comparison of two delivery methods of local anesthetic distribution after intra-articular knee injection.

We studied the intra-articular distribution of radiopaque dye to compare the efficacy of a continuous low-volume infusion with an intermittent high-volume bolus infusion. Knee arthroscopy patients were randomized with 10 cc of dye infused over 2.5 hours versus 10 cc bolus of dye. Radiographs were independently evaluated. Eleven knees (low-volume infusion) filled an average of 3 of 7 compartments, while 10 knees (bolus group) had complete filling of all seven compartments (P < .001). This study supports high-volume bolus injections of local anesthetics to achieve consistent distribution to all knee compartments while enhancing pain control.