Adductor Canal Block Coverage Limitations — FRCA Final MCQ

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ModerateRegional AnaesthesiaAdductor Canal Block Coverage LimitationsFRCA Final

A 60-year-old woman (ASA III) is having a right total knee replacement under spinal anaesthesia with a tibial nerve and common peroneal nerve block for postoperative analgesia (as components of a knee block). Which nerve is NOT blocked by the adductor canal approach and requires a separate block for complete knee analgesia?

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Correct answer: D — Common peroneal nerve

The adductor canal block targets the saphenous nerve, nerve to vastus medialis, and sometimes the posterior branch of the obturator nerve. It does NOT block the sciatic nerve or its terminal branches (common peroneal and tibial nerves). For complete knee analgesia after TKR, particularly for posterior knee pain, additional blockade of the sciatic nerve (or its components – popliteal sciatic block) or periarticular local anaesthetic infiltration by the surgeon is required. The iPACK block (interspace between popliteal artery and capsule of the knee) is increasingly used to address posterior knee pain without causing foot drop.

Reference: RCOA – 2023 – Regional anaesthesia module; Tran DQ – 2019 – Knee block strategies for TKR