Author:

Abstract:

Lateral elbow pain is a common problem in clinical practice. Entrapment of the posterior interosseous nerve (PIN), the deep branch of the radial nerve, may be the origin. The nerve can be compressed traumatically or atraumatically. It is exposed to pressure at different locations during its course through the radial tunnel, especially during repeated pronation and supination. There are two clinical manifestations of the PIN syndrome: on the one hand, there is a clinical picture with a predominant weakness without pain, while on the other hand, a predominant pain without weakness occurs. The first manifestation is easily diagnosed. An electromyography confirms the clinical picture. An ultrasound and an MRI might reveal an underlying cause of the syndrome. The second manifestation however, particularly characterized by subjective pain, is hard to diagnose. It is often confused with a common extensor tendinopathy. Until now, the pathogenesis of this second form is still debated. The treatment of a non-traumatic lesion of the PIN is usually conservative. Surgery is appropriate in case of a structural cause or when a conservative strategy falls short.