Spinal anaesthetic (SA) with intrathecal diamorphine and general anaesthetic (GA) with blocks and/or patient control analgesia (PCA) are commonly used in hip and knee replacement surgery. Drop in blood pressure, feeling light-headed and drowsiness, itching are known early complications respectively. This causes delay in patient mobilization post operatively. Our study examines the use of a local anaesthetic infuser device (LAID) (pain buster pump) for post operative pain relief after total hip or knee replacement surgery.

Forty six patients (25) THRs and (21) TKRs were included in this study. Each were given a LAID which consisted of 0.25% bupivicaine infused at 4ml/hr via an elastometric pump over 48 hours. 100mls of 0.1% bupivicaine with 0.5mg adrenaline was infiltrated locally into the wound at closure. All patients were prescribed regular analgesic as per the multimodal pain regime and an hourly pain score maintained. Rescue opioids were prescribed if pain score crossed 5. Patient satisfaction score was recorded as excellent, some or no pain relief. Eleven patients were given general anaesthetic and 25 patients were given spinal anaesthetic.

26% were able to sit out of bed within 6 hours of surgery and 65% (30 patients) were sitting out by the first post operative day. Average length of stay was 6.15 days, decreased to 4 days for patients mobilised on day zero and compared to eight days prior to this study. 21% had excellent result, 29% had some pain and 6% had poor result. 90% needed oral rescue analgesia within the first 48 hours.

LAID allowed some patients to be mobilised within 6 hours of surgery. The use of LAID helps avoids the need for PCA or diamorphine and hence its associated complications though some amount of oral rescue analgesia was necessary. Patient compliance was satisfactory. The early results are encouraging and further studies are been conducted at our hospital.