A Prospective Comparison of Ultrasound-Guided Ankle Versus Popliteal Nerve Blocks for Elective Forefoot Surgery in a UK Podiatric Surgery Unit.

Abstract

Regional anaesthesia is central to perioperative care in foot surgery, yet comparative data within UK podiatric surgery services remain limited. Establishing local outcome baselines is essential for optimising care and supporting clinical scope. To compare pain intensity levels and functional recovery in patients undergoing elective forefoot surgery under ultrasound-guided ankle or popliteal nerve block. This prospective service evaluation involved 17 adults undergoing elective forefoot surgery. Participants were allocated via pragmatic, nonrandomised sequential scheduling based on surgeon preference to receive either an ultrasound-guided ankle block (n = 9) or popliteal nerve block (n = 8) using 0.5% levobupivacaine. Outcomes included sensory onset time, duration of analgesia, pain intensity (VAS), opioid consumption standardised to morphine milligram equivalents (MME), and functional recovery assessed using a modified Functional Recovery Index (FRI). Sensory onset times showed no significant difference between groups (p = 0.491). Popliteal blocks provided significantly longer analgesia than ankle blocks (23.75 vs. 12.61 hours; p = 0.038), whereas procedural discomfort was comparable (p = 0.449). Postoperative pain trajectories differed significantly (p = 0.049), with pain decreasing from Day 1 to Day 3 following ankle block but increasing following popliteal block. Opioid consumption declined over time across the cohort (p = 0.015), with no significant between-group differences. Functional recovery demonstrated a trend towards greater early improvement in the ankle group. Both ankle and popliteal blocks provided effective perioperative anaesthesia for elective forefoot surgery. Popliteal blocks offered longer analgesia, whereas ankle blocks showed a trend towards earlier mobilisation. Although limited by sample size and Type II error risk, these findings provide baseline data to inform future adequately powered studies and contribute evidence from UK podiatric day-case practice that may have relevance to wider day-case foot surgery.