Pain below the outside of the elbow is not always tennis elbow. Radial tunnel syndrome is a possible nerve-related cause of deep proximal forearm pain, while tennis elbow involves the common extensor tendon origin. The conditions can be difficult to distinguish and may coexist. A diagnosis-led assessment matters before choosing a tendon injection such as platelet-rich plasma (PRP).
If gripping a suitcase, lifting equipment or using a mouse has become uncomfortable, the first task is to locate the problem accurately. Treatment should follow the likely source of pain and its effect on function, rather than the treatment you happened to search for first.
Where is radial tunnel pain felt?
A review of compressive neuropathies describes radial tunnel pain as deep aching in the lateral forearm, typically several centimetres below the bony outer elbow. Tennis elbow is more associated with tenderness at the lateral epicondyle itself. This is a useful distinction for examination, not a reliable self-diagnosis rule.
Pain can overlap, and other conditions can produce a similar pattern. Your clinician should assess where the tenderness is greatest, what movements reproduce symptoms and whether the neck, joint or surrounding tendons could be involved. A generic label of elbow pain does not provide enough information to choose an injection.
Does it cause numbness or weakness?
Classic radial tunnel syndrome is described mainly as pain, without the motor dysfunction associated with posterior interosseous nerve syndrome. Pain can make effort feel weak, but true loss of finger or thumb extension is a different finding and needs clinical attention.
Do not assume new weakness is simply a painful tendon. A clinician may assess wrist, finger and thumb extension and look for other neurological or tendon problems. New or progressive weakness, particularly after an injury, should be assessed promptly rather than waiting for a routine PRP appointment.
Ask about a diagnosis-led assessment
How is the diagnosis assessed?
History and examination are central. Resisted forearm rotation or finger extension may reproduce symptoms, but no single manoeuvre should be treated as definitive proof. The examiner also considers tennis elbow and other potential explanations.
Nerve-conduction studies and electromyography may help investigate alternative diagnoses or motor nerve involvement. They are not uniformly abnormal in radial tunnel syndrome. A normal test therefore needs interpretation alongside the clinical findings rather than an automatic conclusion that the pain cannot be nerve-related.
Will I need an ultrasound or MRI?
Imaging is selected to answer a specific question. A scan may be helpful if a mass, joint disease, trauma or another structural cause is suspected. The neuropathy review describes MRI's role in investigating space-occupying lesions and muscle changes in relevant nerve syndromes.
A scan report should not replace an examination. Ask how a finding relates to the symptoms and whether it changes management. If your pain has persisted despite treatment for tennis elbow, reviewing the original diagnosis may be more useful than repeating the same procedure.
What does this mean for PRP?
PRP research in tendon conditions cannot automatically be applied to nerve compression. A proposed tendon injection should have a clear tendon diagnosis, a reason to expect benefit and an explanation of uncertainty. The sources used for this article do not establish PRP as a standard treatment for radial tunnel syndrome.
That distinction protects your time and your recovery plan. An injection aimed at a tendon will not necessarily address a separate nerve problem. If a clinician proposes any injection around a nerve, discuss the exact purpose, alternatives, anatomical risks and evidence for that specific procedure.
Discuss the right next step for your symptoms
What treatment pathway might follow?
Management depends on the diagnosis, symptom duration, work and sport demands, and neurological findings. A clinician may discuss changes to aggravating activity and an appropriate rehabilitation plan. Persistent or uncertain cases may benefit from a hand or upper-limb specialist opinion.
Avoid repeatedly provoking severe pain with home diagnostic tests. Record which everyday actions cause symptoms instead. If a previous programme made things worse or produced no useful change, bring the details so the next assessment can reconsider the problem rather than simply starting again.
When is more urgent assessment appropriate?
Seek prompt advice for new finger or wrist weakness, increasing loss of function, significant injury or a rapidly worsening condition. A hot swollen joint with fever needs urgent medical assessment. Sudden weakness accompanied by speech, facial or other stroke-like symptoms requires 999.
These warnings are about choosing the right medical pathway. Routine PRP assessment should not delay evaluation of a potentially urgent nerve injury or other acute problem.
What should I bring to an appointment?
Bring previous imaging reports, treatment dates, rehabilitation exercises and a concise description of your work and activities. Be specific about pain versus actual loss of movement. Tell the clinician whether symptoms began suddenly or developed gradually.
At The London PRP Clinic, an enquiry can start with an assessment of the pain source and whether PRP belongs in the plan at all. A clear explanation of diagnosis, options and next steps is the foundation of a worthwhile treatment decision.
Enquire about assessment before choosing PRP
Evidence and further reading
Reviewed for publication: 3 November 2026. General information, not a diagnosis or a substitute for individual medical advice. Appointment route, suitability and complete fees are confirmed for your enquiry.