Radial tunnel syndrome is compression of the radial nerve in the forearm, just below the elbow. It causes a deep ache on the outer side of the forearm that is worse with gripping and twisting, and it is very commonly mistaken for tennis elbow. There is no numbness and usually no weakness, which is a large part of why it gets missed. Most cases settle with activity change, therapy and time. Where the diagnosis is clear and the symptoms have not settled, releasing the nerve relieves the pain. The operation takes 30 to 45 minutes as a day procedure.
What is radial tunnel syndrome?
The radial nerve runs down the outer side of the arm and divides just below the elbow. One of its branches, the posterior interosseous nerve, dives into the forearm muscles through a short tunnel formed by muscle edges, fibrous bands and blood vessels. That tunnel is the radial tunnel, and it runs from the level of the elbow joint to the lower edge of the supinator muscle, a distance of about five centimetres.
The nerve can be squeezed at several points along it. The most common is the arcade of Frohse, a firm fibrous edge at the top of the supinator muscle that the nerve passes underneath. Others are the sharp tendinous edge of one of the wrist extensor muscles, a fan of small blood vessels that crosses the nerve, and the lower edge of the supinator where the nerve emerges.
The branch involved is almost purely a motor nerve, and that is the key to the whole condition. Compression irritates it enough to produce pain but not enough to stop it working. So there is no numbness, because this nerve carries no sensation from the skin of the hand, and usually no weakness. What is left is pain on its own, and pain on its own is a difficult thing to attribute to a nerve. That is why the condition is both under-diagnosed and over-diagnosed, depending on who is looking.
Symptoms
Most people describe:
- A deep, aching pain in the upper forearm on the outer side, a few centimetres below the bony point of the elbow
- Pain that is worse with gripping, and with twisting movements such as turning a screwdriver, using a door handle or wringing out a cloth
- Aching at night, or a forearm that feels tired and heavy after a day of use
- Tenderness when pressing over the muscle a few centimetres below the elbow, rather than on the bony point itself
- A sense of weakness in the grip, usually because gripping hurts rather than because the muscles are actually weak
- No numbness and no pins and needles
If you do have numbness in the hand, the problem is a different nerve or a different site. Carpal tunnel syndrome and cubital tunnel syndrome are the two to think about first.
Radial tunnel syndrome and tennis elbow
These two are confused constantly, in both directions, and it is worth understanding why.
Tennis elbow is a problem of the tendon where the wrist extensor muscles attach to the bony point on the outside of the elbow. Radial tunnel syndrome is a problem of a nerve running through the muscle a few centimetres further down. They hurt in almost the same place, both are aggravated by gripping, and several of the examination tests that are positive in one are also positive in the other.
Three things separate them in practice.
- Where it is tender. Tennis elbow is tender on the bony point itself. Radial tunnel is tender over the muscle roughly four centimetres below it. A small difference in centimetres and a large one in meaning.
- How the pain behaves. Radial tunnel pain tends to be a deeper and more constant ache, and it more often disturbs sleep.
- What has already been tried. Radial tunnel is most often reached as a diagnosis after treatment for tennis elbow has not worked. A lateral elbow that has had rest, therapy and one or two injections and has still not settled is worth reassessing rather than injecting again.
The two can also occur together, so finding one does not exclude the other. Where both are present, treating only one explains why the elbow is better but not right.
Where both are contributing and both need treating, they can sometimes be dealt with in the same operation. That is decided case by case rather than as a routine, and we would talk it through with you beforehand.
Causes and risk factors
- Repetitive forearm rotation under load. Turning, twisting and screwing movements, particularly with tools.
- Forceful repeated gripping. Often in combination with the above rather than on its own.
- A previous elbow injury or fracture, or surgery around the elbow.
- Anatomy. The firmness of the fibrous edges the nerve passes under varies from person to person, and some people simply have a tighter tunnel.
- A space occupying lesion. Uncommon, but a ganglion, a lipoma or a swollen joint lining can press on the nerve, and this is the group in whom a scan changes the management.
In many people there is no clear cause.
How it is diagnosed
This is the difficult part of the condition and it is worth being straightforward about it. There is no single test that proves radial tunnel syndrome. The diagnosis is made by putting the history, the examination and the response to a diagnostic injection together, and by ruling out the conditions that would explain the symptoms better.
Clinical examination
Tenderness over the radial tunnel rather than over the bony point of the elbow. Pain reproduced by resisting rotation of the forearm with the elbow straight, and by resisting extension of the middle finger. Neither test is specific on its own, because both can be positive in tennis elbow. It is the pattern taken together, and the location of the tenderness, that is informative.
Nerve conduction studies
We arrange nerve conduction studies for everyone with this presentation. They serve two purposes, and neither of them is confirming radial tunnel syndrome.
The first is to rule out the problems that would explain your symptoms better. Compression of the other nerves at the wrist and the elbow is commoner than this, more treatable and far easier to confirm, and none of them should be missed while attention is on the forearm.
The second is to record how the nerves are working before anything is done. That baseline is what any later study is measured against, so if the picture changes, or if recovery after an operation is slower than expected, there is something to compare against rather than a guess.
The studies themselves are usually normal in radial tunnel syndrome, because compression here is often intermittent and this is not a nerve that is easy to study electrically. A normal result does not exclude the diagnosis, and that is the single most common reason the condition is dismissed. A normal baseline is still worth having.
Imaging
Not needed to make the diagnosis. An ultrasound or an MRI is useful where something is suspected to be pressing on the nerve, such as a ganglion or a lipoma, or where the elbow joint itself needs assessing.
Diagnostic injection
The most useful test available. A small volume of local anaesthetic is placed into the radial tunnel. If the pain settles for the duration of the anaesthetic, that supports the diagnosis, and it is also the best guide we have to whether an operation will help. If it does not settle, the diagnosis should be questioned rather than the injection repeated.
We arrange this under ultrasound guidance, so that the anaesthetic reaches the tunnel itself rather than the nerve trunk higher up. An injection placed too high numbs the whole forearm, which relieves the pain whatever its cause and therefore tells us nothing.
We would strongly prefer to have a positive block before operating and it is unusual to proceed without one, though a convincing history and examination can carry the decision where a block is equivocal or impractical.
Non-surgical treatment
Most people should start here and many need nothing more. As a general guide we would like around three months of non-surgical treatment behind us before considering an operation, though that is a guide rather than a rule and it moves either way depending on how you are going and how clear the picture is. Recovery here is often slow, and the time is deliberate rather than a delay.
Activity change
The most effective single measure, and the least popular. The movements that provoke it are repetitive forearm twisting and forceful grip, so the useful changes are to tools, technique and the amount of time spent on the aggravating task rather than stopping using the arm.
Hand therapy
Our therapists work on nerve gliding, on the tightness in the forearm muscles that contributes to the compression, and on the grip and forearm mechanics that keep provoking it. Having therapy on site means this starts the same week rather than after another referral.
Splinting
A splint resting the wrist, and sometimes the forearm, reduces the pull of the muscles through the tunnel and can settle symptoms, particularly at night. It suits some people and not others, and it is worth a trial rather than a long commitment.
Corticosteroid injection
An injection of corticosteroid with the local anaesthetic can settle symptoms as well as help confirm the diagnosis. We arrange these under ultrasound guidance rather than injecting in the rooms, for the same reason as above. We would not repeat an injection more than twice at the same site.
Surgery
Radial tunnel decompression releases the structures that are compressing the nerve so that it has room to move. The nerve itself is not repaired or moved. It is freed.
The approach is from the back of the forearm, through the interval between two of the extensor muscles. Every point at which the nerve can be compressed along the tunnel is released: the fan of small vessels crossing it, the tendinous edge of the wrist extensor muscle, the firm fibrous edge at the top of the supinator, and the lower edge of the supinator where the nerve emerges. Releasing all of them matters, because a single tight point left behind is one of the reasons a decompression fails to relieve the pain.
It is a day surgery procedure under a general anaesthetic with a local anaesthetic block for comfort afterwards, and takes approximately 30 to 45 minutes. The incision is closed with dissolving skin sutures, and a tape bandage covers the wound under a soft dressing.
What to expect from the result
Results here are less predictable than for carpal tunnel or cubital tunnel release, and it is better to know that before deciding than afterwards. Where the diagnosis is confident, and particularly where the diagnostic block gave clear relief, most people get good relief of their pain.
Where the diagnosis was uncertain, or where the lateral elbow has more than one thing wrong with it at once, the result is less reliable. That is the main reason we do not rush to operate on this condition, why non-surgical treatment usually runs for some months first, and why the block matters as much as it does.
Recovery, week by week
Indicative, and it varies with your job and with how long the symptoms were present beforehand.
Timeframe
What to expect
Day of surgery
Your forearm and hand may feel numb or tingly for up to 24 hours because of the local anaesthetic block. You can move your fingers before you leave hospital, and you will be encouraged to keep the shoulder and wrist moving.
Days 1 to 4
Keep the soft dressing clean and dry. Keep the arm elevated to reduce swelling. Move your fingers, wrist and shoulder regularly, and move the elbow gently.
Day 4 or 5
You will be referred to a hand therapist. They take down the outer bandage, keep the tape dressing on the skin intact, and start you on gentle elbow and forearm movement.
Days 5 to 14
The tape bandage can get wet in the shower. Dab it dry afterwards. If it comes off, replace it with new tape. Use the hand and wrist as tolerated, and avoid forceful gripping and twisting.
Two weeks
Your progress is reviewed and the wound is checked. The skin sutures dissolve and do not need removing. If needed, a new tape bandage goes on for another three to five days.
Two to six weeks
Increasing use of the arm for light tasks, with therapy progressing movement and starting gentle strengthening. The forearm often aches through this period, which is expected rather than a setback.
Six weeks onwards
A graded return to heavier use and to full strengthening, guided by your hand therapist.
Three months and beyond
The ache in the forearm continues to settle over several months. Nerve pain resolves more slowly than wound pain, and improvement continuing past three months is normal.
Driving and work
Driving and office work at four to five days, once the elbow moves freely. Light manual work two to four weeks. Heavy work six weeks.
Hand therapy
Therapy matters here both before and after surgery. Beforehand it is often what settles the condition without an operation, and it is a large part of what those months before surgery are for.
Afterwards, therapy starts at day 4 or 5, earlier than after most hand operations, because the elbow stiffens quickly and because the nerve needs to glide rather than scar in place. The therapist takes down the dressing, starts gentle elbow and forearm movement at the right pace, manages the swelling and rebuilds grip without returning straight to the loading that caused the problem. Our therapists are on site, so this happens on time rather than at the mercy of another waiting list.
Risks and complications
Radial tunnel decompression is a routine operation and complications are uncommon. They can include:
- Wound healing problems or infection.
- Bleeding or bruising. Usually minor and settles on its own.
- Temporary weakness of finger and thumb extension. The nerve has to be handled to free it and can be slow to settle afterwards. Permanent weakness is rare.
- A numb patch of skin on the back of the forearm, from small sensory nerves near the incision.
- Elbow or forearm stiffness.
- Ongoing pain, or relief that is incomplete. This is more likely after this operation than after carpal tunnel or cubital tunnel release, and more likely where the diagnosis was uncertain to begin with.
- Ongoing tenderness around the scar.
- Another procedure may be required in the future.
When to be seen sooner
Contact us, or see your GP, if you have:
- Weakness extending the fingers or the thumb, or a wrist that will not lift
- Numbness or pins and needles in the hand, which points to a different nerve problem
- Lateral elbow pain that has not settled after several months of appropriate treatment
- A lump appearing in the forearm or around the elbow
- Pain that began suddenly after an injury rather than gradually
If you have had surgery with us and have questions or concerns afterwards, phone the rooms during office hours on (08) 7127 0365.
Other nerve compression in the arm
The ulnar nerve can be compressed at the elbow, which is cubital tunnel syndrome and is much more common than radial tunnel, or at the wrist in Guyon's canal. The median nerve can be compressed at the wrist, which is carpal tunnel syndrome and is the most common of all, or less often in the forearm. Each has its own pattern, and the distribution of the numbness is usually what separates them. Radial tunnel is the odd one out, because it produces no numbness at all.
Frequently asked questions
Is this the same as tennis elbow?
No, although they are easily confused and they can occur together. Tennis elbow is a tendon problem at the bony point on the outside of the elbow. Radial tunnel syndrome is a nerve being compressed in the muscle a few centimetres further down. The tenderness sits in a different place, and radial tunnel more often aches at night. If your tennis elbow has been treated properly and has not settled, this is one of the reasons why.
My nerve conduction test was normal. Does that mean I do not have it?
No. Nerve conduction studies are usually normal in radial tunnel syndrome and a normal result does not exclude it. We arrange them for everyone with this presentation, but not to confirm this diagnosis. They rule out the other nerve compressions that would explain your symptoms better, and they record how your nerves are working before treatment starts, which is the baseline that anything done later is measured against.
Why do I have pain but no numbness?
Because the branch of the nerve involved carries almost no sensation from the skin. It is a motor nerve, so when it is irritated it produces pain rather than numbness. If you do have numbness in the hand, something else is going on and it is worth saying so at your appointment.
Do I need an injection before surgery?
Almost always, yes. The diagnostic block is the most useful test we have. If your pain settles while the local anaesthetic is working, that supports the diagnosis and it is the best guide to whether an operation will help. It is unusual to operate without one, although a very clear history and examination can carry the decision where a block is equivocal or impractical.
How long should I try non-surgical treatment?
Around three months is the usual guide rather than a fixed rule, and it moves either way depending on how you are progressing and how clear the diagnosis is. This condition often settles slowly with activity change and therapy, and operating early on an uncertain diagnosis is the main way people end up disappointed.
How long does the operation take, and will I be asleep?
Approximately 30 to 45 minutes, as a day surgery procedure under a general anaesthetic, with a local anaesthetic block given at the same time for comfort afterwards. You go home the same day.
Do I need my stitches removed?
No. The skin is closed with dissolving sutures. You are still reviewed at two weeks to check the wound and your progress.
Will the surgery definitely fix the pain?
It is the most honest question on this page and the answer is no. Where the diagnosis is confident and the diagnostic block gave clear relief, most people do well. Where the diagnosis was uncertain, or where there is more than one thing wrong with the elbow, results are less reliable than for the commoner nerve releases. We will tell you which of those two situations you are in before you decide.
When can I drive and go back to work?
Driving and office work at four to five days, once the elbow moves freely. Light manual work at two to four weeks. Heavy work at six weeks. There is no legislation covering surgery and driving, so the test is whether you can control the car safely, including in an emergency. Some insurers will not cover damage or liability if you had recent surgery, if you were wearing a splint or a cast while driving, or if you were taking pain medication that could affect your driving, so it is worth contacting your insurer before you plan to drive again. We will give you a realistic estimate for your specific job before the operation, and a certificate.
Can you treat my tennis elbow at the same time?
Sometimes. Where both problems are genuinely contributing and both need treating, they can be dealt with in the same operation. It is decided case by case rather than as a routine, and we would go through it with you beforehand.
Will my arm be weak afterwards?
Usually not in the long term. The nerve has to be handled to free it, so some temporary weakness of finger and thumb extension can occur and can take time to settle. Permanent weakness is rare. Grip often feels stronger once the pain settles, because gripping was what hurt.
What does the surgery cost?
You will receive written informed financial consent setting out the surgeon, anaesthetist and hospital fees, your Medicare rebate and your health fund's contribution before anything is booked. Phone the rooms on (08) 7127 0365 for an estimate.
Do I need a referral?
A referral from your GP or another specialist means you can claim a Medicare rebate on the consultation. We can see you without one, but the rebate will not apply.
Written and clinically reviewed by Dr Paul van Minnen, MD, PhD, EBOPRAS, FRACS (Plast)
Last reviewed 10 September 2026