An extraordinary mechanism causing intraoperative migration of the Kirschner-wire.

Migration of Kirschner wires (K-wires) postoperatively and with use of cannulated implants intraoperatively is a well-known complication. In this article, we present an extraordinary mechanism causing intraoperative migration of a K-wire. A K-wire which was used for temporary fixation of fracture fragments migrated forwardly due to its contact with the drill bit while drilling a hole for a screw. The interaction between the K-wire and the drill bit simulated a gear wheel effect and thus the rotating K-wire advanced. Although no complications occurred in this case, we believe that the mentioned mechanism may be of importance particularly in osteoporotic patients and may cause damage to vital structures.

The efficacy of subcutaneous local analgesic infusion in the early postoperative period after bilateral total knee arthroplasty.

OBJECTIVES: This study aims to evaluate the analgesic and functional efficacy of subcutaneous local analgesic infusion (ScLAI) in the early postoperative period (especially on the second postoperative day) in patients undergoing simultaneous bilateral total knee arthroplasty with an intraoperative periarticular injection (PAI) of local analgesic cocktail. PATIENTS AND METHODS: Fifteen patients (1 male, 14 females; mean age 62 years; range 52 to 76 years) who underwent simultaneous bilateral total knee arthroplasty (30 knees) and who received the same pre- and intraoperative analgesic protocols were included in this randomized, double-blind, placebo-controlled study. By using a flexible catheter, bupivacaine was administered for ScLAI to either knee (ScLAI group) and placebo infusion was applied to the other one (control group). Postoperative visual analog scale (VAS) pain scores and knee functions were compared between bupivacain and placebo infused knees. RESULTS: In the ScLAI group, VAS pain scores were lower than the control group during knee flexion and straight leg raise activities (SLR) on the second postoperative day. ScLAI also prevented the rebound pain following intraoperative PAI of local analgesic cocktail and prolonged the analgesic efficacy period of the cocktail during both knee flexion and SLR. CONCLUSION: Subcutaneous infusion of bupivacaine in patients undergoing simultaneous bilateral total knee arthroplasty may prevent emergence of the rebound pain arising after application of intraoperative PAI of local analgesic cocktail and prolong the analgesic efficacy of the cocktail during both knee flexion and SLR activities on the second postoperative day.