Which landmark or ultrasound-guided nerve block is most appropriate for analgesia following total knee replacement, sparing quadriceps strength for early rehabilitation?

• A Femoral nerve block — excellent analgesia but causes quadriceps weakness impeding rehabilitation
• B Sciatic nerve block — covers posterior knee pain adequately for all TKR patients
• C Spinal anaesthesia with hyperbaric bupivacaine is the only effective analgesia for TKR
• D Adductor canal block (saphenous nerve block) — provides medial knee analgesia via saphenous nerve with minimal quadriceps motor block ✓

Explanation

The adductor canal block (ACB) targets the saphenous nerve (terminal sensory branch of the femoral nerve) within the adductor canal (Hunter's canal) at mid-thigh level. It provides excellent medial and anteromedial knee analgesia with minimal motor blockade of the quadriceps (vastus medialis is largely spared), allowing earlier ambulation and physiotherapy compared to femoral nerve block which causes significant quadriceps weakness and fall risk. IPACK (infiltration between the popliteal artery and the capsule of the knee) block combined with ACB covers posterior knee pain. ACB has largely replaced femoral nerve block in modern TKR ERAS pathways.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.