Intra-operative infiltration of local anaesthetic into peri-operative tissue has become part of the protocol of many units worldwide. It is claimed that this reduces post operative pain and improves the speed of mobilisation thereby improving the comfort of the patient and decreasing the hospital stay.

In order to test the validity of this concept we conducted a prospective randomised controlled clinical trial of 100 patients undergoing primary total hip arthroplasty or hip resurfacing. All procedures were performed by one surgeon (Miss Muirhead-Allwood) using a posterior-lateral approach. Patients were randomised to receive 30ml of 0.5% Marcaine injected under direct vision at the time of closure or no injection (placebo).

Post-operatively patients in both groups received a standardised regime of intravenous infusion of diclofenac for 48 hours and ‘rescue’ intramuscular injections of morphine on demand.

Patients’ pain levels post-operatively were independently recorded using both a verbal rating score (VRS) and a visual analogue scale (VAS) at regular intervals for the first five post-operative days. Periodicity of requests for opiate analgesia was documented. Time taken to reach mobility ‘goals’ were also documented as was time taken to discharge and patient satisfaction with the whole process.

Our results show no significant difference in the two groups previously defined and we suggest that routine use of intracapsular local anaesthetic is not indicated in primary hip replacements and surface replacements provided an adequate post-operative pain regime is already in use.