Abstract
Introduction: Polymodal anaesthesia has become the core approach for the modern anaesthetist. Femoral, sciatic and obturator nerve blockade, individually or in combination, by means of either single shot or continuous infusion, are often used as adjuncts to general anaesthesia in knee arthroplasty.
Methods: We examine the outcome of 2 groups of 100 patients from 2 surgeons and their anaesthetists. All patients received a general anaesthetic. The first group receive a single shot femoral and sciatic nerve block, the second group a standard GA and local infiltration of the surgical field. Post operatively, both groups received identical analgesic regimes and rehabilitation programmes.
Results: Length of stay was prolonged in the nerve blockade group, with 21 of the 100 patients still in hospital on day 6 versus 9 patients in the local infiltration group. An initial advantage in flexion and extension in the nerve blockade group was reversed by day 2 and persisted thereafter. Motor dysfunction was seen to be more prevalent and of longer duration in the nerve blockade group. Muscle groups supplied by the sciatic nerve were 4 times more likely to be involved than those supplied by the femoral nerve. Dysaesthesia in the sciatic nerve dermatomes was 5 times more likely within the nerve blockade group, but less likely in the local infiltration group. No significant difference in rates of VTE. Pain control was superior and less analgesia was required in the nerve blockade group. Fewer patients required urethral catheterisation in the local infiltration group. One heel ulcer occurred in the nerve blockade group. Tourniquet time, significant as a possible contributor to nerve injury, was similar.
Conclusion: Nerve blockade in knee arthroplasty not recommended.
The abstracts were prepared by Mr Matt Costa and Mr Ben Ollivere. Correspondence should be addressed to Mr Costa at Clinical Sciences Research Institute, University of Warwick, Clifford Bridge Road, Coventry CV2 2DX, UK.
