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Lumbar plexus block

We hope the information on this page will be helpful to you. If you have any questions please ask a member of the Pain Relief Clinic nursing staff who will be happy to help you.

The procedure that you have had done to you is known as a lumbar plexus or ‘psoas compartment’ block. It is usually given for pain arising from the hip joint as a result of osteoarthritis, but can also help with other types of hip pain such as residual pain after hip replacements, even though the hip joint is artificial. A common indication is for patients awaiting hip replacement, which may be a wait of several months, to provide better pain relief than pain-killing medication. It can also be given to patients for whom a hip replacement is indicated but who are physically unfit for this major operation.


Treatment and side-effects

Local anaesthetic has been injected on to the nerves which go to the hip joint. The local anaesthetic temporarily numbs the nerves and interrupts the ‘pain cycle’ that keeps the pain going in your hip. It does not destroy the nerves - they recover fully within 24 hours - but the pain that they carry takes a long time to build up again.

For several hours - sometimes until well into the next day - your leg will feel weak and numb, as far down as just below the knee. You may also have 'pins and needles'. You will probably be unable to walk properly until the next day and you should not attempt to do so without help until the leg feels normal again.

The pain relief which results from these blocks can then start immediately or sometimes take a week or two to develop. It can then last for up to 5 or even 6 months. As it is a simple and safe procedure, it can be repeated as often as needed.


If possible, you should go to bed or at least lie down when you return home. The following day try to arrange for someone else to help out so that you are doing the bare minimum, but you do not have to stay in bed.

The pain relief should allow you to gradually increase your activities. It is important that you do not immediately take up unaccustomed exercise until your muscles have time to acclimatise to it. It is suggested that you start exercising in a mild fashion, taking two walks a day but limiting the distance and time to the level that you know you can manage easily.


It would be appreciated if you could contact the clinic (01604) 545065 in four weeks’ time to report the result to us. If you need to see us again, an appointment can be made to see us directly.


Useful websites


Other information

Northampton General Hospital operates a smoke-free policy. This means that smoking is not allowed anywhere on the Trust site, this includes all buildings, grounds and car parks.

Leaflets, information, advice and support on giving up smoking and on nicotine replacement therapy are available from the local Stop Smoking helpline on 0845 6013116, the free national helpline on 0300 123 1044, email: and pharmacies.


Car parking at Northampton General Hospital is extremely limited and it is essential to arrive early, allowing ample time for parking. You may find it more convenient to be dropped off and collected.


This information can be provided in other languages and formats upon request including Braille, audio cassette and CD. Please contact (01604) 523442 or the Patient Advice & Liaison Service (PALS) on (01604) 545784, email:


Updated February 2021

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