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Radial Tunnel Syndrome

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Radial tunnel syndrome — causes forearm pain, weakness straightening fingers, and is distinct from tennis elbow.

Updated Oct 20264 citations

Radial tunnel syndrome causes aching pain in the upper outer forearm, just below the elbow. Kieran Hirpara 4.0

What you're feeling

The main symptom is pain on the outside of your forearm, near your elbow. It is usually worst at a tender spot a few centimetres below the bony point on the outside of your elbow. Pressing on that spot is often sore. The pain can spread down the back of your forearm towards your wrist.

Certain movements make it worse. Turning your palm up against resistance, or straightening your middle finger against resistance, can bring the pain on. So can activity that keeps loading your forearm. Many people notice the pain flares after work or sport rather than at rest.

This condition affects a nerve that supplies muscles rather than skin. That means you are unlikely to have numbness or tingling, and the nerve itself usually works normally. The problem is pain, not weakness or loss of feeling.

Day to day, the pain tends to show up in tasks that need gripping and twisting. Lifting a kettle, turning a door handle, using a screwdriver or wringing out a cloth can all hurt. Because the tender spot sits near the outside of the elbow, this condition is often mistaken for tennis elbow, and the two can occur together.

There is no single test that confirms this condition. Your surgeon reaches the diagnosis from your story and an examination, checking for that specific tender spot and the pattern of your pain.

Watch for these signs. See your GP or ask for a specialist review if your symptoms are not settling, are getting worse over weeks, wake you at night, or stop you working or using your arm. Go to the emergency department the same day if your arm becomes hot, red, swollen and painful, especially with a fever, or if your hand turns pale, cold, white or blue. If you cannot reach the clinic after hours or on a weekend, go to your nearest emergency department.

What's actually happening

The pain comes from a nerve, not from the elbow joint itself. A nerve is a cable that carries signals between your brain and your muscles. One branch of the radial nerve runs down the outside of your forearm, past the elbow, to supply the muscles that straighten your wrist and fingers.

Along that stretch, several separate structures sit close to the nerve. The edge of a muscle, a fibrous band, or a small group of crossing blood vessels can each press on it. This is not one narrow passage. It is more like a walking track with several possible pinch points along the way, any of which can squeeze the cable running beside it.

When one of those structures presses on the nerve, the nerve becomes irritated and sore. That is why the pain sits at a tender spot below the bony point on the outside of your elbow, and why turning your palm up or straightening your middle finger against resistance makes it worse. Those movements pull the muscles this nerve supplies, and the irritated nerve complains.

The nerve still works, so your muscles keep working and you feel no numbness or tingling. The problem is irritation and pain, not loss of signal. Because the sore spot sits so close to the outside of the elbow, the pain is easily mistaken for tennis elbow, which affects a tendon in the same neighbourhood. The two can even happen together.

What we can do about it

Dr Kieran Hirpara, an upper-limb surgeon at Mater Private Hospital Rockhampton, starts with the least invasive options that suit your condition. Patients are generally referred to our clinic by their GP; if a physiotherapist has suggested you see us, you will still need a referral from your GP in order to be eligible for the Medicare rebate. At the clinic we take a history, examine your arm, and arrange imaging if it will help. For this condition we usually try non-operative care first, and consider surgery when that has not given enough improvement.

The first step is changing how you use your arm. Cutting back the gripping and twisting tasks that flare the pain gives the irritated nerve a chance to settle. Hand therapy aims to settle the pain and rebuild your tolerance for loading the forearm, so work and daily tasks become comfortable again. We ask you to give this a fair trial before thinking about anything further.

Pain medication and anti-inflammatories can help you through a flare. They settle the soreness while the other measures do their work. They do not fix the pressure on the nerve itself.

If non-operative care has not given enough improvement, surgery is an option. The operation is called a radial tunnel release. It works by freeing the nerve at each of the places where a nearby structure is pressing on it. Before recommending it, we check carefully where the nerve is being squeezed, so the operation targets the right spot and disturbs as little surrounding tissue as possible. Because the diagnosis rests on your story and examination rather than one clear test, we treat the decision to operate as a shared one, made together once you understand what surgery can and cannot settle.

What to expect

For most people, this condition does not damage the nerve. The nerve keeps working, so your muscles keep working and you do not lose feeling. The problem is pain, and pain from an irritated nerve can take a long time to settle. It rarely goes away overnight, and it often flares with gripping and twisting tasks before it eases.

The honest picture is that this condition is hard to predict. Some people settle with rest, activity changes and hand therapy. Others keep having pain despite good non-operative care. There is no reliable test to confirm the diagnosis, which makes it harder to say in advance which group you will fall into. What we can say is that the pain tends to come and go with how much you load your forearm, rather than building steadily.

If non-operative care works, the pain eases gradually over weeks to months as the nerve becomes less irritated. You would expect to find daily tasks like lifting a kettle or turning a door handle less painful first, before heavier work feels normal again. If surgery is done after non-operative care has not helped enough, recovery is also gradual rather than instant, and some people still have some pain afterwards.

If the condition is left alone, it may settle on its own, but it can also persist or keep flaring whenever you return to the tasks that aggravate it. There is no way to know in advance which will happen. What tends to matter is giving treatment a fair trial and not pushing through pain that is not settling.

If your symptoms are not settling, are getting worse over weeks, wake you at night, or stop you working or using your arm, see your GP or ask for a specialist review. Go to the emergency department the same day if your arm becomes hot, red, swollen and painful, especially with a fever, or if your hand turns pale, cold, white or blue. If you cannot reach the clinic after hours or on a weekend, go to your nearest emergency department.

When to see someone

The warning signs for this condition are about pain that will not settle, not about danger. See your GP or ask for a specialist review if your forearm pain has not settled after a fair trial of rest and activity changes, or if it keeps stopping you working or using your arm. Ask sooner rather than later if the tender spot below the outside of your elbow is a prominent feature, or if turning your palm up or straightening your middle finger against resistance reliably brings the pain on. These patterns point towards this condition rather than tennis elbow, and they are worth sorting out properly.

This condition does not usually damage the nerve, so sudden weakness of your wrist or fingers is not a typical part of it. If you do notice new weakness in straightening your wrist, fingers or thumb, ask for a specialist review promptly rather than waiting, because that pattern suggests a different nerve problem that is assessed on its own timeline.

Go to an emergency department the same day if your arm becomes hot, red, swollen and painful, especially with a fever, or if your hand turns pale, cold, white or blue. If you cannot reach the clinic after hours or on a weekend, go to your nearest emergency department.

In more depth

Advanced reading: the deeper science (optional)

This section goes further than you need for your own treatment decisions. Radial tunnel syndrome is worth the extra reading for an uncomfortable reason: it is the condition on this site with the weakest evidence base, there is no test that confirms it, and being told plainly how uncertain it is should form part of any decision to operate.

There is no confirmatory test

Most nerve compressions can be demonstrated. Carpal tunnel syndrome produces slowed conduction across the wrist; cubital tunnel produces it across the elbow. Radial tunnel syndrome characteristically does not, the nerve branch involved supplies muscle rather than skin, so there is no numbness to map, and nerve conduction studies are frequently normal.

The diagnosis therefore rests on the pattern of pain, tenderness a few centimetres distal to the lateral epicondyle rather than over it, and the response to a local anaesthetic block. Each of those is suggestive; none is definitive. Contemporary reviews describe ongoing controversy regarding both diagnosis and outcomes [1].

The practical consequence is a high rate of confusion with tennis elbow, which sits immediately adjacent and can coexist. Persistent "tennis elbow" that has not responded to good treatment is one of the commonest circumstances in which radial tunnel syndrome is eventually considered.

The evidence for treating it is genuinely thin

A systematic review of interventions found a tendency that surgical decompression might be effective, and, the more remarkable finding, that the effectiveness of conservative treatments is unknown, because for most of them no studies were available at all [2].

That is not the usual "evidence is limited" formulation. For most non-operative treatments offered for this condition, the studies have not been done. Current reviews still place non-surgical management first, with decompression a viable option for refractory cases [1], and that ordering reflects reasonable caution rather than demonstrated superiority.

What that means for a decision

Two things follow, and they pull in opposite directions.

Against early surgery: the diagnosis cannot be confirmed, so an operation may be decompressing a nerve that is not the source. Where a decompression fails, it is often impossible to determine whether the operation was inadequate or the diagnosis was wrong.

For considering it in the right patient: there is no evidence base supporting the alternatives either, so waiting is not the evidence-backed option people assume. It is simply the lower-risk one.

The reasonable position is that a confident diagnosis matters more here than anywhere else on this site, a consistent history, examination localising to the radial tunnel rather than the epicondyle, imaging excluding a space-occupying lesion, and ideally a convincing response to a diagnostic block before an irreversible step is taken.

A related but different problem

Posterior interosseous nerve palsy, weakness of finger and thumb extension rather than pain, is a distinct entity with clearer management. Where imaging shows no compressive lesion, conservative management should be tried first, with surgery reserved for demonstrated compressive lesions and for failure of conservative treatment [3]. Where there is no space-occupying lesion, a trial of non-operative management is advisable, with exploration recommended if there is no sign of muscle recovery after 6 weeks of observation, or if weakness is progressive [4].

Those are concrete thresholds, and their existence is the clearest illustration of the contrast: when the nerve visibly stops working, the literature can say what to do and when. When it only hurts, it cannot.

---

Reviewed by Dr Kieran Hirpara · 7 August 2026.

Talk to your treating clinician for advice specific to you.

For an appointment with the CQ Hand + Upper Limb team, ask your GP about a referral or visit www.cqupperlimb.com.

References for the advanced reading

1. Wolf JM, Patel R, Ghosh K. Radial tunnel syndrome: review and best evidence. J Am Acad Orthop Surg. 2023;31(15):813-9.
2. Huisstede B, Miedema HS, van Opstal T, de Ronde MT, Verhaar JA, Koes BW. Interventions for treating the radial tunnel syndrome: a systematic review of observational studies. J Hand Surg Am. 2008;33(1):72.e1-72.e10.
3. McGraw I. Isolated spontaneous posterior interosseous nerve palsy: a review of aetiology and management. J Hand Surg Eur Vol. 2018;44(3):310-6.
4. Sigamoney KV, Rashid A, Ng CY. Management of atraumatic posterior interosseous nerve palsy. J Hand Surg Am. 2017;42(10):826-30.

Evidence & references

This is the clinical evidence summary written for health professionals. It is technical, and it lists the research this page was built from. You do not need to read it to understand your treatment or to make a decision about it.

Overview

• Radial tunnel syndrome is relatively uncommon but is an important cause of lateral forearm pain [1].
• Clinical examination is a crucial part of the diagnosis of radial tunnel syndrome [1].
• The duration of symptoms averaged 2.3 years before a definitive diagnosis of radial tunnel syndrome was made [2].
• The diagnosis of radial tunnel syndrome remains clinical [5].
• Adherence to a defined protocol is useful in diagnosing radial tunnel syndrome [5].
• The issue surrounding radial tunnel syndrome traditionally has been properly identifying it clinically [7].
• Compression of the radial nerve at the elbow is of moderate frequency compared to the ulnar tunnel syndrome [9].
• A case of bilateral radial tunnel syndrome with signs discordant with traditionally used clinical diagnostic tests was successfully relieved with surgical decompression [6].
• The Rule-of-Nine test effectively specifies the site of tenderness for the diagnosis of radial tunnel syndrome [11].

Anatomy & Pathophysiology

Clinical Presentation & Diagnostic Challenges

• Radial tunnel syndrome is a relatively uncommon but important cause of lateral forearm pain [1].
• Clinical examination is a crucial component of the diagnosis for radial tunnel syndrome [1].
• The average duration of symptoms before a definitive diagnosis of radial tunnel syndrome was 2.3 years [2].
• Prominent focal tenderness in the area of the radial tunnel is a principal diagnostic criterion for radial tunnel syndrome [20].
• In radial tunnel syndrome, symptoms do not occur in the distribution of the purportedly affected nerve, which distinguishes focal tenderness from a positive Phalen's test in carpal tunnel syndrome [20].
• Skeptics note that radial tunnel syndrome presents with normal neurologic function and no confirmatory electrodiagnostic evidence of nerve dysfunction, contrasting with other well-described entrapment neuropathies [20].

Etiology & Pathophysiology

• There is dispute over the etiology of radial tunnel syndrome, with some skeptics questioning its status as a viable entrapment neuropathy [20].
• The posterior interosseous nerve carries unmyelinated (group IV) afferent fibers from the wrist capsule and small myelinated (group IIA) afferent fibers from muscles along its distribution [20].
• Unmyelinated group IV fibers are associated with nociception and pain [20].
• The current best evidence for the conservative management of radial tunnel syndrome consists primarily of expert opinion and inferences from studies on other nerve compressions [3].

Relevant Elbow Anatomy

• The elbow is a trocho-ginglymoid joint consisting of medial and lateral articulations that afford bony stability [63].
• The ulnohumeral joint is formed by the articulation of the trochlea with the ulna within the greater sigmoid notch [63].
• The radiocapitellar joint is formed by the articulation of the capitellum and radial head [63].
• The radius is held in close approximation to the ulna at the proximal radioulnar joint by the annular ligament [63].
• The lateral epicondyle is the origin of the lateral extensor musculature [63].
• The radial nerve enters the interval between the brachialis and brachioradialis muscles in the proximal angle of the lateral approach to the elbow [66].
• The deep branch of the radial nerve enters the supinator muscle [66].
• The posterior interosseous nerve is located just superficial to the anterior joint capsule at the level of the radiocapitellar joint [75].
• At the level of the radial neck, the posterior interosseous nerve may come in direct contact with the joint capsule [75].
• Supination increases the linear distance between the posterior interosseous nerve and the radial head [107].

Classification

• Radial tunnel syndrome (RTS) and posterior interosseous nerve (PIN) compression are distinct entities with different clinical presentations but share identical potential sites of nerve interference [29].
• The author of [29] proposes unifying RTS and PIN compression as mild and severe forms of one disease to simplify nomenclature [29].
• The authors of [52] recommend viewing radial tunnel syndrome and posterior interosseous nerve syndrome as a single condition presenting along a spectrum of nerve entrapment [52].
• Radial tunnel syndrome is a pain syndrome caused by compression of the posterior interosseous nerve at the proximal forearm [22].
• The diagnosis of radial tunnel syndrome remains clinical, and adherence to a defined protocol is useful in diagnosing this condition [5].
• A differential latency of ≥0.30 ms was considered indicative of radial tunnel syndrome [16].
• Radial tunnel syndrome is an illness construct based on a speculative pathophysiology with no verifiable pathophysiology or accepted reference standard for diagnosis [14].
• Skeptics note that the signs and symptoms of RTS contrast from other well-described entrapment neuropathies in that there is prominent focal tenderness, normal neurologic function, and no confirmatory electrodiagnostic evidence of nerve dysfunction [20].
• Prominent focal tenderness in the area of the radial tunnel remains one of the principal diagnostic criteria for RTS [20].
• Focal tenderness at the radial tunnel in RTS differs from a positive Phalen's test in carpal tunnel syndrome in that the symptoms do not occur in the distribution of the purportedly affected nerve [20].
• There has been no randomized controlled trial that compares surgical with nonsurgical treatment or with a placebo for RTS [20].
• Skeptics of RTS point to the great variability of surgical results reported in the literature as one of the characteristics of placebo surgery [20].

Clinical Presentation

• Radial tunnel syndrome is a relatively uncommon cause of lateral forearm pain [1].
• Radial tunnel syndrome and posterior interosseous nerve compression are distinct entities with different clinical presentations [29].
• The author proposes unifying radial tunnel syndrome and posterior interosseous nerve compression as mild and severe forms of one disease to simplify nomenclature [29].
• The authors recommend viewing radial tunnel syndrome and posterior interosseous nerve syndrome as a single condition presenting along a spectrum of nerve entrapment [52].
• Prominent focal tenderness in the area of the radial tunnel is one of the principal diagnostic criteria for radial tunnel syndrome [20].
• In radial tunnel syndrome, symptoms do not occur in the distribution of the purportedly affected nerve, which differs from a positive Phalen's test in carpal tunnel syndrome [20].
• A diagnosis of radial tunnel syndrome should be considered in patients with forearm and wrist pain that has not responded to more conventional treatment [13].
• The diagnosis of radial tunnel syndrome remains clinical, and adherence to a defined protocol is useful in diagnosing the condition [5].
• The issue surrounding radial tunnel syndrome has traditionally been properly identifying it clinically [7].
• A case of bilateral radial tunnel syndrome presented with signs discordant with traditionally used clinical diagnostic tests [6].
• Muscle denervation edema or atrophy along the distribution of the posterior interosseous nerve is the most common MR finding in radial tunnel syndrome [32].
• A symptomatic double-level entrapment of the posterior interosseous branch of the radial nerve has been described [51].
• Compression of the radial nerve at the elbow is of moderate frequency compared to ulnar tunnel syndrome [9].
• The annual incidence rate of posterior interosseous nerve entrapment is estimated to be 0.03% [88].
• The most frequent location of radial nerve entrapment is around the elbow, specifically involving the posterior interosseous nerve branch [88].
• The radial tunnel spans 5 cm, extending from the humero-radial joint and running distally between the deep and superficial heads of the supinator [88].
• The radial tunnel is bounded laterally by extensor carpi radialis longus and extensor carpi radialis brevis muscles and medially by biceps tendon and the brachialis [88].
• The roof of the radial tunnel is formed by brachioradialis [88].
• The floor of the radial tunnel is the elbow-joint capsule [88].
• Potential sites of entrapment in the radial tunnel include capsular tissue of the radiocapitellar joint, hypertrophic crossing branches of leash of Henry, the leading proximal tendinous and medial edge of ECRB, the arcade of Frohse, and the distal border of the supinator between its two heads [88].
• The arcade of Frohse is noted to be the most common site of entrapment in the radial tunnel [88].
• Clinical criteria for radial tunnel syndrome include activity-related pain, maximal tenderness 3–5 cm distal to the lateral epicondyle, pain exacerbation with forearm supination, radiation to the dorsoradial aspect of the forearm, and a positive Lister test [81].
• A clinical diagnosis of radial tunnel syndrome requires 4 of 5 diagnostic signs and symptoms, with one being maximal tenderness 3–5 cm distal to the lateral epicondyle [81].
• Physical examination for radial tunnel syndrome includes wrist flexion and forearm pronation, the Rule of Nines test, and assessment of weakness and pain with resisted long finger extension [86].
• The history for radial tunnel syndrome includes extensor musculature "forearm aching" [86].

Investigations

Clinical Diagnosis

• A diagnosis of radial tunnel syndrome should always be born in mind when dealing with patients with forearm and wrist pain that has not responded to more conventional treatment [13].
• It is important to understand the anatomic course and distribution of the radial nerve in order to make an accurate diagnosis [24].

Electrodiagnostic Studies

Imaging

• Neuroimaging should be considered as a complementary diagnostic method in posterior interosseous neuropathy [132].
• Dynamic ultrasonographic assessment of changes in the AP diameter and CSA is an effective diagnostic tool for identifying radial tunnel syndrome [121].
• Ultrasonography, computed tomography, and magnetic resonance imaging revealed the location of the ganglion in every patient with radial nerve palsy caused by a ganglion [124].
• The authors acknowledge that their study does not establish diagnostic accuracy or a reference standard for radial tunnel syndrome [49].

Treatment

Non-Operative Management

• Current best evidence for the conservative management of radial tunnel syndrome consists primarily of expert opinion and inferences taken from studies on other nerve compressions and related syndromes [3].
• The effectiveness of conservative treatments for radial tunnel syndrome is unknown because, for most treatments, no studies are available [48].
• Prospective evaluation of a single corticosteroid injection demonstrated improvement in standardized outcomes measures of pain and function at one year in 75% of patients presenting with symptoms of radial tunnel syndrome [8].
• Nonsurgical management is first-line for radial tunnel syndrome [4].
• The two most common nerve entrapment disorders about the elbow, including radial tunnel, should be initially managed conservatively before considering surgical intervention [80].

Operative Management

• Surgical decompression remains a viable option for refractory cases of radial tunnel syndrome despite ongoing controversy regarding diagnosis and outcomes [4].
• There is a tendency that surgical decompression of the radial tunnel might be effective in patients with radial tunnel syndrome [48].
• The authors advocate for surgery in high radial nerve entrapment neuropathy cases resistant to conservative treatment, emphasizing the importance of dissecting the entire length of the fibrous tunnel [17].
• This study indicates that pain in patients with radial tunnel syndrome may be treated successfully by surgical decompression of the superficial branch of the radial nerve [104].
• The results of radial tunnel release have been sufficiently good thus far as to warrant some attention, with an overall significant improvement in 99 of 108 cases (91.7%) when combined with other series [19].
• Nineteen patients (20 extremities) felt satisfied and helped and believed they gained improved function because of surgical decompression of the radial tunnel [27].
• The authors believe that a high rate of morbidity is associated with both the disease and its treatment, suggesting that great caution has to be taken before performing radial tunnel release [26].
• The authors suggest that great caution be taken before performing radial tunnel release and strict adherence to the indications noted during the preoperative examination [50].

Evidence Limitations and Controversy

• There has been no randomized controlled trial that compares surgical with nonsurgical treatment or with a placebo for radial tunnel syndrome [20].
• Skeptics of radial tunnel syndrome point to the great variability of surgical results reported in the literature as one of the characteristics of placebo surgery [20].
• Although radial tunnel syndrome is classically described as a nerve compression and entrapment syndrome, there is dispute over its etiology [20].

Complications

• A high rate of morbidity is associated with both radial tunnel syndrome and its treatment [26].
• In a case of congenital compression of the radial nerve, the patient was followed for an additional 3 months without clinical improvement in radial nerve function [12].
• Nerve injury is an uncommon though troublesome complication of fractures or dislocations of the elbow [39].

Recovery

• A patient with congenital compression of the radial nerve was followed for an additional 3 months without clinical improvement in radial nerve function [12].
• In a patient with posterior interosseous-nerve syndrome secondary to rheumatoid synovitis where the duration of entrapment was more than two years, a tendon transfer was used as treatment [139].
• Isolated posterior interosseous nerve neurectomy has shown excellent clinical outcomes, with few patients experiencing recurrent pain at long-term follow-up [123].

Key Evidence

• [L5] Radial tunnel syndrome is relatively uncommon but is an important cause of lateral forearm pain, with clinical examination being a crucial part of the diagnosis. [1] (10.1197/j.jht.2006.02.005)
• [L4] The duration of symptoms averaged 2.3 years before a definitive diagnosis of radial tunnel syndrome was made. [2] (10.1016/s0363-5023(83)80201-9)
• [L5] Current best evidence for the conservative management of radial tunnel syndrome (RTS) consists primarily of expert opinion and inferences taken from studies on other nerve compressions and related syndromes. [3] (10.1197/j.jht.2006.02.020)
• [L4] The article reviews the anatomy, diagnosis, and treatment of radial tunnel syndrome, noting that while nonsurgical management is first-line, surgical decompression remains a viable option for refractory cases despite ongoing controversy regarding diagnosis and outcomes. [4] (10.5435/jaaos-d-23-00314)
• [L4] The diagnosis of radial tunnel syndrome remains clinical, and adherence to a defined protocol is useful in diagnosing this condition. [5] (10.1016/s0266-7681(98)80015-6)
• [L5] A case of bilateral radial tunnel syndrome with signs discordant with traditionally used clinical diagnostic tests was successfully relieved with surgical decompression. [6] (10.1177/15589447211029045)
• [L5] The issue surrounding radial tunnel syndrome traditionally has been properly identifying it clinically. [7] (10.1097/01.bth.0000231580.32406.71)
• [L4] Prospective evaluation of corticosteroid injection demonstrated improvement in standardized outcomes measures of pain and function at one year in 75% of patients presenting with symptoms of radial tunnel syndrome. [8] (10.1016/j.jhsa.2017.06.095)
• [Paper] Compression of the radial nerve at the elbow is of moderate frequency compared to the ulnar tunnel syndrome. [9] (10.1016/j.main.2004.10.006)
• [L4] The Rule-of-Nine test effectively specifies the site of tenderness for the diagnosis of radial tunnel syndrome. [11] (10.1177/230949900401200115)
• [L5] The patient was followed for an additional 3 months, without clinical improvement in radial nerve function. [12] (10.1016/s0363-5023(89)80099-1)
• [L4] A diagnosis of radial tunnel syndrome should always be born in mind when dealing with patients with forearm and wrist pain that has not responded to more conventional treatment. [13] (10.1016/s0266-7681(05)80152-4)
• [L5] Radial tunnel syndrome is an illness construct based on a speculative pathophysiology with no verifiable pathophysiology or accepted reference standard for diagnosis. [14] (10.1016/j.jhsa.2010.03.020)
• [L4] A differential latency of ≥0.30 ms was considered indicative of radial tunnel syndrome. [16] (10.1016/s0363-5023(98)80163-9)
• [Case_report] The authors advocate for surgery in high radial nerve entrapment neuropathy cases resistant to conservative treatment, emphasizing the importance of dissecting the entire length of the fibrous tunnel. [17] (10.1016/j.jse.2025.02.060)
• [L4] The results of radial tunnel release have been sufficiently good thus far as to warrant some attention, with an overall significant improvement in 99 of 108 cases (91.7%) when combined with other series. [19] (10.1016/s0363-5023(79)80105-7)
• [L5] [20] (10.1016/j.jhsa.2009.10.016)
• [L5] Radial tunnel syndrome is a pain syndrome caused by compression of the posterior interosseous nerve at the proximal forearm. [22] (10.1016/j.ocl.2012.07.022)
• [L5] It is important to understand the anatomic course and distribution of the radial nerve in order to make an accurate diagnosis. [24] (10.1007/s11420-011-9238-8)
• [L5] The authors believe that a high rate of morbidity is associated with both the disease and its treatment, suggesting that great caution has to be taken before performing radial tunnel release. [26] (10.1097/00130911-200212000-00010)
• [L4] Nineteen patients (20 extremities), however, felt satisfied and helped and believed they gained improved function because of surgical decompression of the radial tunnel. [27] (10.1016/s0363-5023(97)80086-x)
• [L5] Radial tunnel syndrome (RTS) and posterior interosseous nerve (PIN) compression are distinct entities with different clinical presentations but share identical potential sites of nerve interference; the author proposes unifying them as mild (RTS) and severe (PIN compression) forms of one disease to simplify nomenclature. [29] (10.1177/1753193420953990)
• [L4] Muscle denervation edema or atrophy along the distribution of the posterior interosseous nerve is the most common MR finding in radial tunnel syndrome. [32] (10.1148/radiol.2401050028)
• [L4] Nerve injury is an uncommon though troublesome complication of fractures or dislocations of the elbow. [39] (10.1016/s0020-1383(79)80015-7)
• [L4] [48] (10.1016/j.jhsa.2007.10.001)
• [Paper] The authors acknowledge that their study does not establish diagnostic accuracy or a reference standard for radial tunnel syndrome. [49] (10.1177/17531934261463150)
• [L4] The authors suggest that great caution be taken before performing radial tunnel release and strict adherence to the indications noted during the preoperative examination. [50] (10.1053/jhsu.1999.0566)
• [L5] A symptomatic double-level entrapment of the posterior interosseous branch of the radial nerve is described. [51] (10.1016/s0363-5023(83)80202-0)
• [L5] The authors advocate for consistent use of the terminology distinguishing the deep branch of the radial nerve (DBRN) and the posterior interosseous nerve (PIN), and recommend viewing radial tunnel syndrome and posterior interosseous nerve syndrome as a single condition presenting along a spectrum of nerve entrapment. [52] (10.1177/17531934241254706)
• [L2] [81] (10.1016/j.jhsa.2024.09.023)
• [L5] [88] (10.1016/j.jisako.2024.03.001)
• [L4] This study indicates that pain in patients with radial tunnel syndrome may be treated successfully by surgical decompression of the superficial branch of the radial nerve. [104] (10.1177/1753193408099832)
• [L5] Supination increases the linear distance between the PIN and radial head and should be considered to increase the safe working volume whenever intra-articular procedures are performed on the anterolateral aspect of the elbow. [107] (10.1016/j.jse.2018.08.019)
• [L4] Dynamic ultrasonographic assessment of changes in the AP diameter and CSA is an effective diagnostic tool for identifying radial tunnel syndrome. [121] (10.1177/17531934261443138)
• [L4] Isolated PINN have shown excellent clinical outcomes, with few patients experiencing recurrent pain at long-term follow-up. [123] (10.1177/1558944717692093)
• [L4] Ultrasonography, computed tomography, and magnetic resonance imaging revealed the location of the ganglion in every patient. [124] (10.1016/s0363-5023(10)80102-9)
• [L4] Neuroimaging should be considered as a complementary diagnostic method in PINS. [132] (10.1212/wnl.0000000000003287)
• [L4] In the third patient, in whom the duration of entrapment was more than two years, a tendon transfer was used as treatment. [139] (10.2106/00004623-197355040-00009)

References

[1] Radial Tunnel Syndrome: A Surgeon's Perspective. Journal of Hand Therapy. 2006. DOI: 10.1197/j.jht.2006.02.005

[2] Radial tunnel syndrome: A spectrum of clinical presentations. The Journal of Hand Surgery. 1983. DOI: 10.1016/s0363-5023(83)80201-9

[3] Management of Radial Tunnel Syndrome: A Therapist's Clinical Perspective. Journal of Hand Therapy. 2006. DOI: 10.1197/j.jht.2006.02.020

[4] Radial Tunnel Syndrome: Review and Best Evidence. Journal of the American Academy of Orthopaedic Surgeons. 2023. DOI: 10.5435/jaaos-d-23-00314

[5] Radial Tunnel Syndrome: Diagnosis and Management. Journal of Hand Surgery. 1998. DOI: 10.1016/s0266-7681(98)80015-6

[6] Radial Tunnel Syndrome: Case Report and Comprehensive Critical Review of a Compression Neuropathy Surrounded by Controversy. HAND. 2021. DOI: 10.1177/15589447211029045

[7] A Unified Approach to Radial Tunnel Syndrome and Lateral Tendinosis. Techniques in Hand & Upper Extremity Surgery. 2006. DOI: 10.1097/01.bth.0000231580.32406.71

[8] Prospective Evaluation of Single Corticosteroid Injection in Radial Tunnel Syndrome. The Journal of Hand Surgery. 2017. DOI: 10.1016/j.jhsa.2017.06.095

[9] Compressions du nerf radial au coude. Chirurgie de la Main. 2004. DOI: 10.1016/j.main.2004.10.006

[11] A New Clinical Test for Radial Tunnel Syndrome—The Rule-of-Nine Test: A Cadaveric Study. Journal of Orthopaedic Surgery. 2001. DOI: 10.1177/230949900401200115

[12] Congenital compression of the radial nerve. The Journal of Hand Surgery. 1989. DOI: 10.1016/s0363-5023(89)80099-1

[13] Radial Tunnel Syndrome. Journal of Hand Surgery. 1995. DOI: 10.1016/s0266-7681(05)80152-4

[14] Radial Tunnel Syndrome. The Journal of Hand Surgery. 2010. DOI: 10.1016/j.jhsa.2010.03.020

[16] Differential latency testing: A more sensitive test for radial tunnel syndrome. The Journal of Hand Surgery. 1998. DOI: 10.1016/s0363-5023(98)80163-9

[17] High radial nerve entrapment neuropathy: an anatomical cadaver study and case report. Journal of Shoulder and Elbow Surgery. 2025. DOI: 10.1016/j.jse.2025.02.060

[19] The radial tunnel syndrome. The Journal of Hand Surgery. 1979. DOI: 10.1016/s0363-5023(79)80105-7

[20] Unusual Compression Neuropathies of the Forearm, Part I: Radial Nerve. The Journal of Hand Surgery. 2009. DOI: 10.1016/j.jhsa.2009.10.016

[22] Radial Tunnel Syndrome. Orthopedic Clinics of North America. 2012. DOI: 10.1016/j.ocl.2012.07.022

[24] Posterior Interosseous Neuropathy: Electrodiagnostic Evaluation. HSS Journal®: The Musculoskeletal Journal of Hospital for Special Surgery. 2012. DOI: 10.1007/s11420-011-9238-8

[26] Radial Tunnel Syndrome. Techniques in Hand and Upper Extremity Surgery. 2002. DOI: 10.1097/00130911-200212000-00010

[27] Radial tunnel syndrome: Long-term results of surgical decompression. The Journal of Hand Surgery. 1997. DOI: 10.1016/s0363-5023(97)80086-x

[29] Radial tunnel syndrome: definition, distinction and treatments. Journal of Hand Surgery (European Volume). 2020. DOI: 10.1177/1753193420953990

[32] MR Imaging Features of Radial Tunnel Syndrome: Initial Experience. Radiology. 2006. DOI: 10.1148/radiol.2401050028

[39] Acute nerve injury as a complication of closed fractures or dislocations of the elbow. Injury. 1979. DOI: 10.1016/s0020-1383(79)80015-7

[48] Interventions for Treating the Radial Tunnel Syndrome: A Systematic Review of Observational Studies. The Journal of Hand Surgery. 2008. DOI: 10.1016/j.jhsa.2007.10.001

[49] Re: Role of high-resolution dynamic ultrasonography in the evaluation of posterior interosseous nerve compression at radial tunnel: a prospective case-control study. Journal of Hand Surgery (European Volume). 1934. DOI: 10.1177/17531934261463150

[50] Results of surgical treatment for radial tunnel syndrome. The Journal of Hand Surgery. 1999. DOI: 10.1053/jhsu.1999.0566

[51] Double-entrapment radial tunnel syndrome. The Journal of Hand Surgery. 1983. DOI: 10.1016/s0363-5023(83)80202-0

[52] Nomenclature of the radial nerve: distinguishing between the deep branch of the radial nerve and the posterior interosseous nerve. Journal of Hand Surgery (European Volume). 2024. DOI: 10.1177/17531934241254706

[63] Orthopaedic Knowledge Update 13 Ebook Without Multimedia. Anatomy, Biomechanics, Physical Examination, and Imaging of the Elbow > Anatomy > Bony Anatomy.

[66] Campbell S Operative Orthopaedics 4 Volume Set. LATERAL APPROACHES.

[75] Green S Operative Hand Surgery. PERTINENT ANATOMY AND PORTALS.

[80] Orthopaedic Knowledge Update 13 Ebook Without Multimedia. Elbow Degenerative Conditions and Nerve Disorders > Summary.

[81] Investigating the Effect of Triamcinolone Local Injection on Clinical Outcomes of Patients With Radial Tunnel Syndrome: A Placebo-Controlled Clinical Trial. The Journal of Hand Surgery. 2025. DOI: 10.1016/j.jhsa.2024.09.023

[86] Orthopaedic Knowledge Update 13 Ebook Without Multimedia. Anatomy, Biomechanics, Physical Examination, and Imaging of the Elbow > Biomechanics > Clinical Examination.

[88] Current concepts of surgical approach for radial nerve entrapment around the elbow. Journal of ISAKOS. 2024. DOI: 10.1016/j.jisako.2024.03.001

[104] Radial Tunnel Syndrome: Emphasis on the Superficial Branch of the Radial Nerve. Journal of Hand Surgery (European Volume). 2009. DOI: 10.1177/1753193408099832

[107] The posterior interosseous nerve crosses the radial head midline and increases its distance from bony structures with supination of the forearm. Journal of Shoulder and Elbow Surgery. 2019. DOI: 10.1016/j.jse.2018.08.019

[121] Role of high-resolution dynamic ultrasonography in the evaluation of posterior interosseous nerve compression at radial tunnel: a prospective case-control study. Journal of Hand Surgery (European Volume). 2026. DOI: 10.1177/17531934261443138

[123] Outcomes Following Isolated Posterior Interosseous Nerve Neurectomy: A Systematic Review. HAND. 2017. DOI: 10.1177/1558944717692093

[124] Diagnosis of radial nerve palsy caused by ganglion with use of different imaging techniques. The Journal of Hand Surgery. 1991. DOI: 10.1016/s0363-5023(10)80102-9

[132] Posterior interosseous neuropathy. Neurology. 2016. DOI: 10.1212/wnl.0000000000003287

[139] Posterior Interosseous-Nerve Syndrome Secondary to Rheumatoid Synovitis. The Journal of Bone & Joint Surgery. 1973. DOI: 10.2106/00004623-197355040-00009