Abstract
Introduction: We performed a prospective double blind randomised clinical trial to measure the effect of pre-operative infiltration of local anaesthetic around arthroscopy wounds compared to post-operative infiltration on post operative pain relief. The underlying clinical principle is for therapeutic intervention to be made in advance of the pain rather than as a reaction to it.
Methods: 36 patients undergoing daycase unilateral knee arthroscopy between October 2000 and March 2001 were studied. The pre-operative group had 10ml 0.25% bupivicaine infiltrated around the arthroscopy portal site following induction of general anaesthesia (G.A.), the postoperative group received 10ml 0.25% bupivicaine after the procedure but before reversal of the G.A. Pain was assessed using a 10cm Visual Analogue Score (VAS) at pre-operative, 1, 2 and 24 hours post operative. At each assessment the patients were blinded to the previous scores that they had submitted. Oral analgesic use in the post-operative 24 hours was also recorded.
Results: There were 18 patients in each group. The mean Visual Analogue Pain Scores (VAS) were lower in the post-op group (1.3) compared to the pre-op group (1.58) at pre-operative assessment. However this difference was not statistically significant (p=0.5607).
At 1 hour post-op the mean VAS in the post-op group was 1.58 and in the pre-op group 2.59. This difference was not statistically significant (p=0.18).
The mean VAS at 2 hours post-op in the pre-op, group was 1.76 compared to 1.82 in the post-op group. This difference was not statistically significant (p=0.9932).
At 24 hours the pre-op group had a lower mean VAS (2.25) than the post-op group (2.4). This difference was however not statistically significant (p=0.7418).
Analysis of the post-operative analgesia requirement in both groups failed no reveal a statistically significant difference (p=0.3965).
Conclusion: In daycase knee arthroscopy under general anaesthesia there is no beneficial role in the use of pre-emptive local anaesthetic infiltration around the arthroscopy portal sites as compared to post-operative infiltration.
The abstracts were prepared by Mr Roger Smith. Correspondence should be addressed to him c/o British Orthopaedic Association, Royal College of Surgeons, 35-42 Lindoln’s Inn Fields, London WC2A 3PN.
