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When Tennis Elbow Treatment Doesn’t Work, This Is the First Thing to Reconsider
Radial tunnel syndrome is a squeezed nerve just below the outer elbow. It causes a deep, aching pain in the upper forearm, three or four finger-widths below the bony point, usually WITHOUT numbness. Most people settle with 3 to 6 months of changing how they twist and grip, a night splint and nerve gliding. Surgery is for the minority who don’t.
You were diagnosed with tennis elbow. You did the eccentric loading, wore the strap, had the injection, gave it months.
BUUUUUUUUUT it just doesn’t get better, and the pain has always felt slightly lower down the forearm than where everyone keeps pressing.
That gap matters.
Radial tunnel syndrome produces an aching, deep forearm pain that mimics tennis elbow closely enough to be treated as tennis elbow for a year. Another round of tendon treatment won’t touch it, cos the tendon was never the main problem.
The single most useful distinction is where the tenderness is.
Tennis elbow is tender right on the bony point. Radial tunnel is tender three or four finger-widths below it, in the muscle bulk of the upper forearm.
What is the radial tunnel?
The radial nerve runs down the outside of the arm, crosses the elbow, and splits.
One branch handles sensation on the back of the hand. The other, the posterior interosseous nerve, dives into the forearm muscles to run the ones that straighten your fingers and thumb.
Over roughly five centimeters of that dive it passes several tight spots:
- fibrous bands in front of the radial head,
- a cluster of small vessels crossing it,
- the firm edge of one of the wrist extensor muscles, and then
- the arch it enters as it burrows into the supinator muscle.
That very arch is where most of the trouble sits.
Two things squeeze it there. Repeated forceful twisting of the forearm, because the supinator itself contracts around the nerve. And repeated gripping with the elbow straight, which is a lot of jobs and most racquet and throwing sports.
Radial tunnel syndrome symptoms: pain, not numbness
This is the confusing part, and worth being clear on.
The branch being compressed is almost purely a motor nerve. It doesn’t supply skin. So radial tunnel syndrome produces pain without numbness, which is not what most people expect from a trapped nerve.
- A deep, tiring ache in the upper outer forearm.
- Often worse at night, and worse after a day of gripping.
- Can radiate up towards the elbow or down towards the wrist.
- Grip feels weak, but because it hurts, not because the muscles have stopped working.
If the same nerve is compressed hard enough to actually stop working, you get a different problem entirely: weakness with no pain, and fingers that won’t lift. That’s posterior interosseous nerve palsy, and it’s a separate article. Numbness or burning on the back of the thumb is the OTHER branch, and that’s Wartenberg’s syndrome.
Is it tennis elbow or radial tunnel? Three things to check yourself
- Where the tenderness lives. Press on the bony point of the outer elbow, then press about four finger-widths below it into the meat of the forearm. Radial tunnel is worse at the second spot. Compare against your other arm.
- Resisted middle finger. Straighten your elbow, straighten your fingers, and have someone push down on your middle finger only while you resist. Pain in the upper forearm rather than at the elbow points at the radial tunnel.
- Resisted twisting. Elbow straight, palm down. Try to turn your palm upwards against resistance. Deep forearm pain there is the supinator working, and the supinator is where the nerve is.
Tender on the bone: tendon. Tender below the bone, in the muscle: think nerve.
Not sure the pain is even in this spot? Elbow pain by location and forearm pain by location sort the lookalikes.
How is radial tunnel syndrome diagnosed?
I’d rather say this than have you find it elsewhere and wonder.
Radial tunnel syndrome is genuinely contested. There’s no test that settles it: nerve conduction studies are frequently normal, because the compression is intermittent and dynamic rather than constant. Some surgeons treat it routinely and some doubt it’s a distinct condition at all.
- Examination is the backbone: the tenderness spot and the two resisted tests above, plus a check that finger and thumb lifting strength is normal.
- A diagnostic injection of local anesthetic into the radial tunnel is the closest thing to proof. Pain that disappears for a few hours afterwards is meaningful evidence.
- Ultrasound or MRI mainly rules things out, such as a ganglion or a fatty lump near the radial head pressing on the nerve. That’s uncommon, but it changes the plan completely.
It also frequently coexists with tennis elbow rather than replacing it, which is part of why the picture gets muddy. Having one doesn’t rule out the other.
(What I’d take from that: it’s a reasonable thing to raise if you’ve failed months of good tennis elbow treatment. It’s not a reasonable first assumption.)
Radial tunnel syndrome treatment
Almost all of the work is load management, and the loads are specific.
- Stop the repeated forceful twisting. Screwdrivers, wringing, ratchets, jar opening, serving and topspin in racquet sports. This is the biggest single lever. Use a power drill, an electric jar opener, a wrench with a longer handle.
- Avoid gripping hard with the elbow straight. Bend the elbow and the nerve loads differently. Carry things closer to your body, palm up where you can.
- Night splint. Keeps the elbow bent, the forearm turned palm-up and the wrist slightly extended, which takes tension off the nerve. Worn at night, usually trialed for 6 to 8 weeks.
- Rethink the strap. A tennis elbow strap sits almost exactly over the radial tunnel. Some people find it helps. If yours makes the ache worse, it’s pressing on the nerve, so take it off. See the tennis elbow counterforce strap.
- Nerve gliding and gentle loading (below).
- Then time. A meaningful trial is 3 to 6 months, not 3 to 6 weeks.
Exercises for radial tunnel syndrome
None of these should reproduce sharp pain. Mild stretch is fine. Tingling that lingers more than a minute after means ease off.
- Radial nerve glide. Stand with your arm by your side, elbow straight. Turn your palm to face backwards, curl your fingers and bend your wrist down. Gently draw your hand back and slightly away from your body until you feel a mild pull along the forearm. Hold 2 seconds, release. 10 reps, twice a day.
- Wrist extensor stretch. Elbow straight, palm down. Use the other hand to gently bend the wrist down. Hold 20 to 30 seconds, 3 reps, twice a day. Ease off if it lights up the nerve ache.
- Forearm turning, unloaded. Elbow bent at your side, palm up then palm down, slowly. 10 reps, 3 times a day. Keeps the supinator moving without squeezing it.
- Isometric holds (from week 2 to 4, if settling). Elbow bent to 90 degrees. Hold your wrist up against your other hand without moving. Hold 10 seconds, 5 reps, twice a day.
- Light strengthening (from week 6, if settled). Wrist curls palm down with a light weight (a full water bottle), 2 sets of 15, once a day. Build slowly. Twisting strength comes back last.
How long does radial tunnel syndrome take to settle?
Good news on the window. Pain-only radial tunnel doesn’t run on a clock. The nerve is irritated, not being destroyed, so time is on your side and there’s no penalty for giving conservative care a proper go.
The window only starts closing if WEAKNESS appears: fingers or thumb that won’t lift fully. That means the nerve has stopped conducting, and that one shouldn’t wait.
- Weeks 0 to 2: load changes and the night splint. Many people notice the night ache easing first.
- Weeks 2 to 6: nerve glides, stretches and isometrics added. Day-to-day ache should be trending down, even if gripping still provokes it.
- Weeks 6 to 12: graded strengthening and a gradual return to heavier work and sport.
- Months 3 to 6: the point to judge it. Clearly better? Keep going. No change at all? That’s when the diagnostic injection and the surgery conversation come in.
Can I work, drive and play sport with radial tunnel syndrome?
- Desk work: yes. Keep the mouse close, forearm supported, and avoid a death grip on it.
- Manual work: usually yes, with the twisting cut back. Power tools over hand tools. Swap tasks across the day.
- Driving: yes. Hold the wheel lightly, and avoid long drives with your arm stretched straight.
- Gym: pulling and pressing are often fine with a neutral or palm-up grip. Heavy straight-arm gripping (deadlifts, farmer’s carries) and wrist-curl variations wait until it settles.
- Racquet sports: drop the topspin-heavy shots and serving volume first. A slightly bigger grip and lower string tension take some load off. Full return usually by weeks 8 to 12 if the ache is settling.
When does surgery come in?
Surgical decompression releases the tight points along the tunnel. It’s considered after 3 to 6 months of proper conservative care has failed, ideally with a convincing response to a diagnostic injection.
Recovery is roughly 6 to 12 weeks back to normal use: desk work within 1 to 2 weeks, light lifting from about 4 to 6 weeks, heavy gripping from about 8 to 12 weeks. A deep ache can take a few months longer to fully settle.
The honest framing is that results are less predictable than tennis elbow surgery. Patients who responded well to a diagnostic injection tend to do better than those who didn’t.
Get it checked today if
- After an injury or a crush, the forearm is tight, swollen and the pain is out of proportion, especially when someone straightens your fingers. That’s acute compartment syndrome, and it’s an ER visit.
- You suddenly can’t lift your fingers or thumb.
- The forearm is red, hot and swollen, with fever.
Get it checked if
- Finger or thumb lifting is getting weaker, even slowly.
- You can feel a lump near the outer elbow or upper forearm.
- Numbness or burning appears on the back of the hand or thumb.
- Night pain is still waking you after 6 weeks of splinting and load changes.
- No meaningful change after 3 months of proper conservative care.
Months of tendon treatment can’t fix a nerve problem. Press four fingers lower before you try round two.
Written by Nigel Chua, hand occupational therapist in practice since 2005. Thousands of hands, wrists and elbows assessed and treated. My credentials are here. This article explains; it doesn’t examine. Forearm pain with actual weakness, rather than just pain, needs assessing now.
Every article on this site is written using the Closing Window Method: name the window your condition runs on, find where you are in it, and act while it’s still open.