Background and Aims Early mobilisation is key for improved outcomes following knee replacement surgery¹ which is limited by good analgesic control in the postoperative rehabilitation phase. A novel sensory ultrasound guided block has been proposed involving the genicular nerve (GNB), iPACK, adductor canal (ACB) and femoral nerve (FNB) to achieve optimal postoperative analgesia and mobilisation. It is our aim to determine if this modified technique reduces opioid use, time to mobilisation and length of hospital stay (LOS) compared to other methods of perioperative analgesia for patients undergoing knee replacement surgery.

Methods Notes were collected retrospectively following approval from the local governing body for patients undergoing knee replacement surgery. A total of 30 notes were obtained; 16 patients with the novel sensory block (GNB, iPACK, ACB, and FNB) (modified); and 14 patients undergoing all other perioperative analgesic interventions (non-modified). Case notes were analysed and data collected regarding time to first mobilisation, opioid requirements postoperatively (morphine equivalents) and LOS.

Results When comparing the modified to the non-modified group; average opioid use in morphine equivalents were 81mg vs 91mg; LOS 2.6 vs 2.6 days and time to mobilisation to a standing position 6.9h vs 10.2h respectively

Conclusions Although a small population size, a modified novel regional block may reduce the time to mobilisation in patients following knee replacement surgery. Institutional bias including regular opioid prescriptions, limited staff availability and fixed discharge planning may account for no difference seen in opioid use and LOS.