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Maryland Orthopedic Specialists
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Elbow

Radial Tunnel Syndrome

Radial tunnel syndrome is an often-overlooked cause of lateral forearm pain resulting from compression of the posterior interosseous nerve (PIN) — the deep motor branch of the radial nerve — as it passes through the radial tunnel near the elbow. It is frequently misdiagnosed as refractory tennis elbow, delaying appropriate treatment. At Maryland Orthopedic Specialists, careful physical examination allows us to distinguish the two conditions and direct the right therapy from the start.

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What is radial tunnel syndrome?

Radial tunnel syndrome is compression of the posterior interosseous nerve — a branch of the radial nerve — as it passes through the radial tunnel near the outer elbow. It causes deep, aching pain in the forearm without the weakness or numbness of true nerve palsy, and is frequently mistaken for lateral epicondylitis (tennis elbow).

The radial tunnel extends from the radiocapitellar joint to the distal edge of the supinator muscle, a span of approximately 5 cm. The posterior interosseous nerve — a purely motor branch — travels through this tunnel and is susceptible to compression at several anatomic sites, most importantly the arcade of Frohse: the fibrous proximal edge of the supinator muscle that arches over the nerve.

Additional compression points include the fibrous bands anterior to the radiocapitellar joint, the radial recurrent vessels (the "leash of Henry"), and the distal edge of the supinator.

Key distinction from tennis elbow:

  • Tennis elbow (lateral epicondylitis): maximal tenderness over the lateral epicondyle (ECRB origin).
  • Radial tunnel syndrome: maximal tenderness 4–5 cm distal to the lateral epicondyle, over the radial tunnel / arcade of Frohse.
  • Radial tunnel syndrome typically produces aching forearm pain without the classic grip-strength weakness of other nerve compression syndromes; pure motor deficit (PIN palsy with finger/wrist drop) is a distinct, more severe entity.
  • Both conditions can co-exist.

Risk factors include repetitive forearm pronation/supination, repetitive elbow extension, lipoma or ganglion within the tunnel, and prior radial head fracture.

Treatment options

Conservative

A 3 to 6 month trial of conservative therapy is recommended before considering surgery. Activity modification reduces repetitive supination and pronation, while physical therapy addresses forearm flexibility, nerve gliding, and progressive strengthening. Elbow extension splinting is helpful when flexion postures aggravate symptoms. NSAIDs manage day-to-day discomfort, and a corticosteroid injection into the radial tunnel can provide meaningful relief in refractory cases and serves as both a therapeutic and diagnostic tool.

Surgical Procedure

Elbow Arthroscopy

Minimally invasive joint scope to address loose bodies, osteochondritis dissecans, posterior impingement, and selected cases of refractory lateral epicondylitis through small portals at the elbow.

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Frequently Asked Questions

Why was I told I have tennis elbow when it's really radial tunnel?
The two conditions produce overlapping lateral arm/forearm pain. The key differentiator is tenderness location: at the epicondyle (tennis elbow) versus 4–5 cm more distal (radial tunnel). Both can coexist.
Will I lose the ability to use my fingers?
Radial tunnel syndrome is a pain syndrome without motor loss. True PIN palsy (with finger/wrist drop) is a separate, more serious diagnosis that requires urgent evaluation.
Is surgery often needed?
No — most patients improve with conservative management. Surgery is reserved for those who remain symptomatic after a thorough non-operative trial.
How is radial tunnel syndrome treated without surgery?
Non-operative treatment focuses on reducing nerve compression and allowing inflammation to settle. This includes activity modification to avoid repetitive forearm rotation and elbow extension, anti-inflammatory medications, and a forearm or elbow splint to rest the area. Physical therapy addresses nerve mobilization (neurodynamic techniques) and stretching of the structures at the radial tunnel. Corticosteroid injections can be helpful diagnostically and therapeutically. Most patients with true radial tunnel syndrome who commit to conservative management for 3–6 months experience meaningful improvement without surgery.
What does recovery from radial tunnel surgery look like?
After surgical decompression of the radial nerve at the radial tunnel, patients typically wear a soft dressing for 1–2 weeks and can begin gentle elbow motion shortly after the procedure. Return to light desk work is possible within 2–4 weeks, while return to heavier manual labor or repetitive forearm use usually takes 6–12 weeks. Nerve recovery is gradual — if nerve compression was longstanding, complete resolution of pain or weakness may take 3–6 months or longer. Your MOS surgeon will guide your rehabilitation and set realistic expectations based on how long symptoms were present before decompression.

Meet the specialists

Peter G. Fitzgibbons, MD

Peter G. Fitzgibbons, MD

Hand Surgery · Orthopedic Surgery

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Related conditions

Posterior Elbow Impingement
Medically reviewed by Peter G. Fitzgibbons, MD, MD
Last reviewed June 16, 2026

References

  1. Roles NC, Maudsley RH. Radial tunnel syndrome: resistant tennis elbow as a nerve entrapment. Journal of Bone and Joint Surgery — British Volume. 1972;54(3):499–508. https://doi.org/10.1302/0301-620X.54B3.499
  2. Sotereanos DG, Varitimidis SE, Giannakopoulos PN, Westkaemper JG. Results of surgical treatment for radial tunnel syndrome. Journal of Hand Surgery. 1999;24(3):566–570. https://doi.org/10.1053/jhsu.1999.0566
  3. American Academy of Orthopaedic Surgeons. Radial Tunnel Syndrome — OrthoInfo. https://orthoinfo.aaos.org/en/diseases--conditions/radial-tunnel-syndrome (accessed May 2026).
  4. Naam NH, Nemani S. Radial tunnel syndrome. Orthopedic Clinics of North America. 2012;43(4):529–536. https://doi.org/10.1016/j.ocl.2012.07.022