Duration of analgesia and factors associated with block failure in ultrasound-guided ankle and popliteal/saphenous nerve blocks in elective foot and ankle surgery: A prospective observational study

Journal

The Foot

Year

2026

Background

Regional anaesthesia is central to perioperative analgesia in foot and ankle surgery. Ultrasound-guided ankle and popliteal/saphenous nerve blocks are widely used, yet real-world evidence on their duration of action and factors associated with block failure is limited. This study aimed to document the duration of postoperative analgesia achieved with levobupivacaine ankle and popliteal/saphenous blocks and to explore contributors to failed or incomplete blocks.

Materials & Methods

Ninety-two consecutive feet undergoing elective foot and ankle surgery received general anaesthesia with an ultrasound-guided ankle (n = 63) or popliteal (n = 29) block. The primary outcome was duration of postoperative analgesia, defined as time from block completion to first rescue analgesia. Secondary outcomes included sensory and motor recovery, pain scores, adverse events, satisfaction, and same-day discharge. Block failure was defined by early rescue analgesia, repeat block, pain-related delayed discharge, or unplanned postoperative contact.

Results

Forty-four ankle and eighteen popliteal blocks were successful. The mean duration of analgesia was 25.95 ± 11.25 h for ankle blocks and 22.25 ± 9.46 h for popliteal blocks. At 24 h, persistent sensory deficit occurred in 22 ankle and 15 popliteal blocks, reducing to one popliteal deficit at 48 h. No neurological injury, infection, readmission, A&E attendance, or helpline contact occurred. Despite a higher-than-expected failure rate, no single causative factor was identified; shorter soak-time before incision emerged as the most plausible contributor.

Conclusion

Ultrasound-guided ankle and popliteal/saphenous blocks using levobupivacaine provided prolonged, safe, and effective analgesia. Variable soak-time appears to be a key modifiable factor influencing block reliability and warrants further investigation.

Resources and Links

Phone Number: +603 2781 4519 / +603 2781 4520

https://www.sciencedirect.com/science/article/abs/pii/S0958259226000118?via%3Dihub

Consultant Name

Dr Nik Aizah Nabilla Faheem

[email protected]

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