NO REDUCTION IN OPIOID REQUIREMENTS OR PAIN WITH REPEATED INTRAARTICULAR APPLICATION OF LOCAL ANAESTHESIA AFTER OSTEOSYNTHESIS OF FEMORAL NECK FRACTURE.

Abstract

Introduction: Recently there has been increasing interest in postoperative pain treatment by use of wound infil-tration with local anaesthetics. The technique has been reported effective following hip and knee arthroplasty. We hypothesized that repeated installations of intraar-ticular local anaesthetic in patients with femoral neck fracture would give pain relief without side effects and reduced opioid usage.

Material and Methods: 33 patients undergoing osteo-synthesis with two Hook Pins were randomized into 2 groups in a double-blinded study (Clinical Trials.gov id: NCT00529425). In group A (Active) 19 patients received 1 peroperative (30 ml=200 mg) and 6 postoperative (10 ml=100 mg) bolus instillations of ropivacaine through an intraarticular catheter which was removed after 48 hours. In group B (placebo) 14 patients were injected with the same volume of saline water. The need for opioid rescue analgesia standardized to mg equivalent of oxyco-done and pain measured on a 5 point scale were recorded during the intervention period of two days after surgery.

Results: No significant difference in consumption of rescue analgesia was found between the groups on day one and two: Group A (16.7 mg and 15 mg, both median values) opposed to group B (10 mg and 7.5 mg, both median values), (P=0.51 and P=0.36 Mann-Whitney). Testing for insufficient use of rescue analgesia by comparing the number of pain scores exceeding a defined limit of tolerable pain showed no difference between the groups on day 1 and 2 (P=0.31 and P=0.45). Comparing the maximum pain score we found no significant difference between the groups on day 1 (P=0.41). Although not significant, the maximum pain score was higher in group A on day 2 (P=0.051). There was no difference between the median pain score on day 1 (P=0,78) but on day 2 the median pain score was significantly higher in group A (P=0,03).

Conclusion: Repeated intraarticular application of ropi-vacaine provides no reduction in opioid requirements or pain after osteosynthesis of femoral neck fracture. This suggests that the technique has no clinically relevant analgesic effect in this category of patients.