Intra-articular “Cocktail” Offers Clinical Advantages over Femoral Nerve Block for Postoperative Analgesia in Patients Undergoing Arthroscopic Hip Surgery

OBJECTIVES: Arthroscopic hip surgery has gained considerable popularity over the past several years. Attempts to optimize peri and postoperative pain control continues to represent a challenge and opportunity for clinical improvement. Multiple regional anesthesia strategies have been utilized by arthroscopic hip surgeons, including lumbar plexus and femoral nerve blockade, however these options can be associated with setbacks including technical difficulty, intravascular injection, increased post-operative fall risk and the development of peripheral neuritis. Therefore, exploration of alternative regional anesthesia strategies holds promise for improved clinical outcomes. This study aims to explore the efficacy and complication rate of intra-articular anesthetic administration in patients undergoing arthroscopic hip surgery. METHODS: A retrospective analysis of prospectively collected data was conducted to identify all patients undergoing elective arthroscopic hip surgery between November 2013 and April 2015. Subjects were stratified into either a group that had received a preoperative femoral nerve block for perioperative pain control or a group that had an intra-articular injection of local anesthetic administered by the surgical team intraoperatively. Objective data, including pre and post-op pain scores in the PACU, total dose of narcotics required perioperatively, occurrence of falls and development of peripheral neuropathy were collected for analysis. Data was compared between the two groups using linear and logistic regression modeling. Statistical significance was determined as p<0.05. RESULTS: After excluding patients who did not meet the criteria for study participation, a total of 193 patients were included in this study. At the time of surgery, one hundred eighty three patients (95%) demonstrated evidence of labralchondral pathology and bony morphology characteristic of femoroacetabular impingement (FAI). One hundred five patients (54%) received a pre-operative femoral nerve block and 88 patients (46%) received an intra-operative intra-articular injection of anesthetic agents. Linear models for post-operative pain, controlled for patient age and pre-operative pain levels, revealed that patients receiving pre-operative femoral nerve blocks had significantly less pain at discharge (p<0.05). There was no statistically significant difference in pain scores between patients receiving pre-operative femoral nerve blocks and those receiving intra-articular injections at post-operative weeks 1, 3 and 6. Patients receiving pre-operative femoral nerve blocks were found to be 3.6 times more likely to experience a post-operative fall (OR 3.58, p < 0.05) and were 14 times more likely to experience post-operative neuropathy (OR 13.99, p < 0.01) than patients receiving an intra-articular injection. CONCLUSION: Intra-articular anesthetic administration was found to be similar in efficacy to pre-operative femoral nerve blocks at reducing post-operative pain in patients undergoing hip arthroscopy. Additionally, patients receiving intra-articular injections had a significantly decreased risk of falling post-operatively or developing peripheral neuritis, known complications of femoral nerve blocks. With this information, intra-articular anesthetic administration appears to be a safe alternative to femoral nerve blocks in patients undergoing hip arthroscopy.