Glossary
Nerve block (adductor canal block)
Quick answer
A nerve block is an injection of local anaesthetic around a specific nerve to numb part of the leg. The adductor canal block, given in the inner thigh, eases knee pain for many hours while largely keeping the thigh muscle working, explains Doha knee surgeon Dr. Pablo Gelber at Aman Hospital.
What it is
Using an ultrasound probe to see the nerves, the anaesthetist places a fine needle and injects local anaesthetic close to the target nerve. For knee surgery the common choice is the adductor canal block, in a channel along the inner middle thigh, which numbs sensory nerves to the front and inside of the knee.
Other blocks can be added for the back of the knee. Sometimes a thin catheter is left to extend the effect.
Why it matters for patients
Good pain control in the first day lets you move, start exercises and walk sooner, and reduces the need for strong opioid tablets. Because the adductor canal block mostly spares the quadriceps, early walking is usually safer than with older femoral nerve blocks.
The block typically lasts somewhere between 12 and 24 hours. Starting regular pain tablets before it wears off avoids a sudden jump in pain.
How it is given
It is usually given just before or after surgery, alongside a spinal or general anaesthetic. Side effects are uncommon: bruising, brief tingling or, rarely, longer-lasting numbness. Use your walking aid as advised, because the leg can feel less reliable while the block is working.
Frequently asked questions
Why did my knee start hurting the night after surgery?
That is often the block wearing off. Taking the prescribed pain relief on schedule, before the numbness fully fades, helps keep pain steady.
Is a nerve block given for ACL surgery too?
Often, yes. Many ACL reconstructions and other major knee procedures use a nerve block to make the first night more comfortable.
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