Radial Tunnel Syndrome
1. Introduction
Radial tunnel syndrome is a less common type of upper limb compressive neuropathy (nerve irritation) compared to conditions such as carpal or cubital tunnel syndrome (1,4). Usually, this condition involves the posterior interosseous nerve (PIN). This is a branch of the radial nerve that is responsible for movement (1, 7). It runs from just below a bony structure of the humerus bone of the elbow called the lateral epicondyle, underneath/through a muscle called the supinator and into the radial tunnel (2,6,1). The radial tunnel is a small space formed by the surrounding structures of the radial nerve, such as blood vessels and muscles (1,7,3). This tunnel is where the nerve irritation or compression can occur due to a narrowing of the space (2). There can be several reasons for such narrowing, which will be explained in more detail in the causes section.
Frequently Asked Questions
Radial tunnel syndrome affects a nerve (posterior interosseous) running on the outer aspect of the upper forearm and most commonly presents with pain. (1)
- Not common.
- Although nerve compression conditions of the upper limb are not rare, those that involve the radial nerve occur less frequently (1,4).
- Radial tunnel syndrome involves the posterior interosseous nerve (a branch of the radial nerve) and has an annual incidence rate of approximately 0.003% of the general population (8).
- No.
- With the right rehabilitation approach this generally recovers well.
- It is not linked to other serious conditions.
- It is reported that those between 30 to 50 years of age are more likely to develop this condition (8).
- Females develop this condition more frequently than males (4,8).
- Pain in forearm just below the elbow and on the outside of the arm (4,1,5).
- Pain may radiate down the forearm to the wrist and fingers (4).
- Tenderness over the lateral forearm area (1, 2, 8).
- May be aggravated by repeated movements, such as straightening the elbow, rotating the forearm or flexing the wrist (4, 8).
- Pain may be worse at night (4, 8).
- You could experience muscle weakness (likely due to pain) or mild sensory changes in the forearm (1, 4).
- Following the advice provided by your physiotherapist is important.
- Activity modification – try to avoid aggravating movements and use your symptoms as a guide (2).
- Splinting the forearm may be advised (2).
- Occupational Health- advice around potential workplace adaptations to reduce aggravation of symptoms.
- Recovery tends to take place within 3 – 6 months (8).
We recommend consulting a musculoskeletal physiotherapist to ensure exercises are best suited to your recovery. If you are carrying out an exercise regime without consulting a healthcare professional, you do so at your own risk. Book online with us today to get a programme tailored to your specific needs.
2. Signs and Symptoms
Symptoms can vary between people, in location and in severity. Some of the most common symptoms are detailed below.
- Pain usually experienced on the outside of the forearm just below the elbow (4,1,5).
- Pain may radiate down the forearm towards the wrist and fingers (4).
- You may find that your pain is aggravated by repeated movements, such as straightening the elbow, rotating the forearm or flexing the wrist (4,8).
- It could also become more noticeable at night (4,8).
- Usually when the lateral forearm area is pressed or palpated, it will feel tender (1,2,8).
- Finally, it is possible you will experience muscle weakness (likely due to pain) or sensory changes in the forearm (1, 4).
3. Causes
There is research to suggest that the main cause of symptoms can be due to the irritation or compression of the radial nerve in the radial tunnel (3), however the exact reason for compression is debated.
As this tunnel is a small space, any narrowing in size will likely impact the structures inside. A common cause of narrowing is swelling as this reduces the space available in the tunnel, making the nerves more susceptible to compression or irritation. Swelling can occur for several reasons, such as:
- Diabetes.
- Thyroid conditions.
- Rheumatoid arthritis.
- Renal problems.
- Injury or trauma to the forearm (such as a fracture).
- Fluid retention during pregnancy. (2)
Other research suggests that repeated rotation movements of the forearm can cause intermittent and dynamic compression of the radial nerve (1), for example during work related activities.
4. Risk Factors
This is not an exhaustive list. These factors could increase the likelihood of someone developing radial tunnel syndrome. It does not mean everyone with these risk factors will develop symptoms.
- It is reported that those between 30 to 50 years of age are more likely to develop this condition (8).
- Females can develop this condition more frequently than males (4,8).
- Being clinically overweight.
- Movements or work involving repetitive forearm rotation (7,1).
5. Prevalence
Nerve compression conditions of the upper limb are common, but those that involve the radial nerve occur less frequently than those involving the median or ulnar nerve (1,4).
Radial tunnel syndrome that involves the posterior interosseous nerve (a branch of the radial nerve) has an annual incidence rate of approximately 0.003% of the general population (8).
6. Assessment & Diagnosis
Musculoskeletal physiotherapists and other appropriately qualified healthcare professionals can provide you with a diagnosis by obtaining a detailed history of your symptoms. A series of physical tests might be performed as part of your assessment to rule out other potentially involved structures and gain a greater understanding of your physical abilities to help facilitate an accurate working diagnosis.
Your treating clinician will want to know how your condition affects you day-to-day so that treatment can be tailored to your needs and personalised goals can be established. Intermittent reassessment will ascertain if you are making progress towards your goals and will allow appropriate adjustments to your treatment to be made.
7. Self-Management
As part of the sessions with your physiotherapist, they will help you to understand your condition and what you need to do to help you recover. This may include reducing the amount or type of activity, as well as other advice aimed at reducing your pain, such as using a splint to offload the forearm (2). It is important that you try and complete the exercises you are provided as regularly as possible to help with your recovery. Rehabilitation exercises are not always a quick fix, but if done consistently over weeks and months then they will, in most cases, make a significant difference.
8. Rehabilitation
Research is very clear that modifying activities and the stress on the nerve is the key element which stimulates recovery (2, 5).
Below are three rehabilitation programmes created by our specialist physiotherapists targeted at addressing radial tunnel syndrome. In some instances, a one-to-one assessment is appropriate to individually tailor targeted rehabilitation. However, these programmes provide an excellent starting point as well as clearly highlighting exercise progression.
9. Radial Tunnel Syndrome
Rehabilitation Plans
Our team of expert musculoskeletal physiotherapist have created rehabilitation plans to enable people to manage their condition. If you have any questions or concerns about a condition, we recommend you book an consultation with one of our clinicians.
What Is the Pain Scale?
The pain scale or what some physios would call the Visual Analogue Scale (VAS), is a scale that is used to try and understand the level of pain that someone is in. The scale is intended as something that you would rate yourself on a scale of 0-10 with 0 = no pain, 10 = worst pain imaginable. You can learn more about what is pain and the pain scale here.
The basic programme is the earliest stage of rehabilitation and so it serves as an introduction to exercise and movement. It is designed to maintain the flexibility of the soft tissues of the forearm and wrist, as well as to increase the mobility of the radial nerve through nerve gliding exercises.
- 0
- 1
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- 910
The intermediate plan is the next progression of the basic plan and the focus changes to firmer stretches for the forearm and wrist to improve nerve, tendon and muscle flexibility/mobility. It also places more emphasis on strengthening the forearm and wrist muscles (especially those that rotate the forearm) using relatively little equipment, such as a resistance band or a weight.
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- 1
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- 3
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- 5
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- 7
- 8
- 910
Finally, the advanced programme is the last progression, and it is tailored towards those who require a higher level of function. It comprises of more challenging and complex exercises which will load the affected structures in the forearm and wrist more to build muscle strength and improve resilience.
- 0
- 1
- 2
- 3
- 4
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- 7
- 8
- 910
10. Return to Sport / Normal life
For patients wanting to achieve a high level of function or return to sport, we would encourage a consultation with a physiotherapist as you will likely require further progression beyond the advanced rehabilitation stage.
As part of a comprehensive treatment approach, your musculoskeletal physiotherapist may also use a variety of other pain-relieving treatments to support symptom relief and recovery. Whilst recovering you might benefit from further assessment to ensure you are making progress and to establish appropriate progression of treatment. Ongoing support and advice will allow you to self-manage and prevent future reoccurrence.
11. Other Treatment Options
Pain relief medications can help ease your symptoms. For example, non-steroidal anti-inflammatory medications (NSAIDS) can alleviate pain (2), however it is advised that you consult with an appropriate healthcare professional prior to starting any medication.
In rare cases corticosteroid injections (2) can also be used as an adjunct to physiotherapy if symptoms are more severe and pain cannot be managed, or if pain is excessively exacerbated by exercise. This is injected locally to the tender area of your forearm to provide short-term pain relief (4). Again, this might enable you to move your arm more so you can progress with your rehabilitation.
Conservative treatments are recommended for a trial of 6 months (4) as they are non-invasive and have positive outcomes on function. However, if you have sufficiently tried all other non-surgical treatments and they have not been successful in reducing your symptoms, then a specialist opinion with a view of surgery could be an option (8).
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References
- Patterson JMM, Medina MA, Yang A, et al. (2022) Posterior interosseous nerve compression in the forearm, AKA radial tunnel syndrome: a clinical diagnosis Hand. 10(1), pp.42-45
- S Silver, CC Ledford, KJ Vogel and JJ Arnold (2021) Peripheral nerve entrapment and injury in the upper extremity. American Family Physician. 103 (5) pp275-285
- Lepich, T., Karaś, R., Kania, K., Machnik-Broncel, J., Barszczewski, K., Szewczyk, W., & Bajor, G. (2024). Anatomical and clinical aspects of the posterior interosseous nerve of the forearm. Medical Studies, 40(1), pp61.
- Bo Tang, J. (2020) Radial tunnel syndrome: definition, distinction and treatments. Journal of Hand Surgery (European Volume), 45(8), pp.882-889.
- Marchese, J., Coyle, K., Cote, M., and Wolf, J.M. (2019) Prospective evaluation of a single corticosteroid injection in radial tunnel syndrome. HAND, 14(6), pp.741-745.
- Thurston, A. (2013) Radial tunnel syndrome. Orthopaedics and Trauma, 27(6), pp.403-408.
- Perez, C.S., Medrano, B.G., Mateos, J.I.R., Martin, B.C., Martin, O.F., and Ferrero, M.A.M. (2014) Radial tunnel syndrome: results of surgical decompression by a postero-lateral approach. International orthopaedics, 38(10), pp.2129-2135.
- Moradi, A., Ebrahimzadeh, M.H., and Jupiter, J.B. (2015). Radial tunnel syndrome, diagnostic and treatment dilemma. Archives of Bone and Joint Surgery, 3(3), p.156.