Femoral Nerve Block

Adductor Canal block

Sciatic Nerve Block

Usual volume of LA (mls)



10 - 15

10 - 20

10 - 25

Nerves covered

Terminal sensory branches of obturator, CPN and

tibial nerves

Local & systemic effects

Femoral nerve

Saphenous nerve

Posterior Tibial nerve at popliteal fossa


Safer blocks than central neuraxial blocks especially in patients with coagulopathy or patients on antiplatelet agents.

1) Localised to periarticular region with sparing of vastus muscles;

2) Minimal weakness thus facilitates early rehabilitation;

3) Relatively easy to perform with lower risk of nerve injury;

4) Potential of covering saphenous nerve.

1) Performed by surgeon and thus less concern of graft infection;

2) Studies have shown that it works as well as Femoral nerve block;

3) Do not require additional ultrasound machine/trained anaesthetist.

1) Simple and superficial block that can be performed by most anaesthetist;

2) Proven to have opioid sparing and pain scores in knee procedures [2] .

1) Simple and superficial block that can be performed by most anaesthetists;

2) Avoids blockade of the vastus lateralis and vastus intermedius with less impairment of hip flexion.

1) Definitive coverage of the posterior knee;

2) Relatively easy to perform.


1) Relatively deep block compared to the other peripheral nerve blocks;

2) LA spread may affect sciatic nerve with potential of motor blockade;

3) Performed near surgical site hence risk of surgical site contamination;

4) New technique with few studies;

5) Few anaesthetists performs the technique;

6) Ideal approach and volume yet to be determined.

1) Large volume required with risk of LA toxicity;

2) Variability in technique, volume and concoction by various surgeons;

3) Not pre-emptive and hence risk of wind up phenomenon.

1) Results in motor blockade with risk of fall and delayed rehabilitation;

2) Has not been found to be more advantageous than multimodal analgesia [2] ;

3) Does not cover posterior aspect of the knee.

1) Blocked performed at site of tourniquet may increase the risk of nerve injury (direct pressure, LA axonal toxicity and needle penetration);

2) May still block the branches to the Vastus medial is if large volume is given;

3) The Adductor canal or sub Sartorius definition is still controversial.

1)Foot drop may occur if the common peroneal nerve is blocked;

2) May delay rehabilitation and discharge;

3) Does not cover anterior aspect of the knee.