12/06/2026
𝐑𝐚𝐝𝐢𝐚𝐥 𝐓𝐮𝐧𝐧𝐞𝐥 𝐒𝐲𝐧𝐝𝐫𝐨𝐦𝐞: 𝐓𝐡𝐞 𝐒𝐭𝐮𝐛𝐛𝐨𝐫𝐧 "𝐓𝐞𝐧𝐧𝐢𝐬 𝐄𝐥𝐛𝐨𝐰"
Lateral elbow pain is almost instantly diagnosed as Lateral Epicondylitis (Tennis Elbow). But when traditional tendon-loading exercises, braces, and friction massages fail to bring relief, the true culprit is often neurological: Radial Tunnel Syndrome (RTS).
Recent literature emphasizes that this nerve entrapment is consistently under-recognized, leading patients to undergo months of ineffective tendinopathy treatments for what is actually a compression neuropathy.
👉 What Is Radial Tunnel Syndrome?
RTS is the compression of the deep branch of the posterior interosseous nerve (PIN), a branch of the radial nerve, as it passes through the proximal forearm.
Unlike most nerve compressions that cause numbness and tingling, RTS primarily causes deep, aching pain. Because it doesn't present with classic cutaneous sensory loss, it easily flies under the radar.
👉 Pathophysiology
The radial nerve can be pinched at dynamic anatomical choke points around the elbow. The most frequent site of entrapment is the proximal aponeurotic edge of the supinator muscle, known as the Arcade of Frohse.
Normal pressure inside the radial tunnel is around 50mmHg, but with passive stretching of the supinator (like forced wrist flexion), the pressure can drastically increase to 250mmHg, crushing the nerve.
👉 Typical Pain Distribution
Patients typically present with:
• A deep, aching pain in the dorsoradial proximal forearm
• Pain that increases during forearm rotation and lifting activities
• Muscle weakness that is secondary to pain rather than actual muscle denervation
👉 Key Clinical Signs
Several clinical findings can differentiate RTS from classic Tennis Elbow:
✔️ Maximal Tenderness Location: In lateral epicondylitis, tenderness is directly over the epicondyle. In RTS, maximal tenderness is located 3 to 5 centimeters distal to the lateral epicondyle, right over the mobile wad of the supinator arch.
✔️ Provocative Testing: Passive forearm pronation combined with wrist flexion directly reproduces pain at the radial tunnel.
✔️ Diagnostic Ultrasound: Neuromuscular ultrasound can now identify the presence of distal pseudoneuromas and nerve edema in chronic RTS cases.
👉 Why It Is Frequently Misdiagnosed
Because both conditions share a region and trigger movements, RTS is frequently confused with lateral epicondylitis; in fact, the two conditions coexist in approximately 5% of patients.
👉 Evidence-Based Treatment Approaches
Treating the extensor tendon won't decompress the nerve.
📌 Conservative management
• Activity modification is the first line of treatment, specifically avoiding prolonged elbow extension combined with forearm pronation and wrist flexion
• Temporary splinting to restrict provocative ranges of motion
• Strengthening and mobility exercises to enhance flexibility and prevent further compression
📌 Interventional options
• Local triamcinolone (corticosteroid) injections are frequently used, though recent 2024 placebo-controlled trials suggest they may not offer superior long-term clinical outcomes compared to placebo.
• Surgical decompression (approached dorsally or volarly) remains an option for refractory cases.
📌 Clinical Takeaway
If your "Tennis Elbow" patient has point tenderness in the muscle belly rather than the bone, stop loading the tendon. Shift your focus to decompressing the radial nerve to finally break the cycle of chronic pain.
✅ References
• Hand (N Y), 2026 – Clinical Outcomes of Operative Management for Radial Tunnel Syndrome According to Surgical Approach: A Systematic Review.
• Clinical Neurophysiology, 2025 – Diagnostic neuromuscular ultrasound of radial tunnel syndrome with the presence of a distal pseudoneuroma.
• Journal of Hand Surgery, 2024 – Investigating the Effect of Triamcinolone Local Injection on Clinical Outcomes of Patients With Radial Tunnel Syndrome: A Placebo-Controlled Clinical Trial.
