What is the anterior interosseous syndrome?
Anterior interosseous syndrome is caused by entrapment of the anterior interosseous branch of the median nerve.
It can be provoked by blunt trauma or repetitive flexion at elbow and wrist such as using an ice pick.
The site of entrapment is between the tendinous origins of the pronator teres and the flexor digitorum superficialis.
On occasion, it is caused by either a viral or inflammatory process.
Symptoms include pain in the forearm and wrist. Easy fatigability and weakness in the distal flexors of the thumb and index finger are often noted.
Creating a tight O-ring sign with the thumb and index finger is not possible; instead a flattened, weak pinch is made.
How is anterior interosseous syndrome treated?
Antiinflammatory medications, local steroid/anesthetic injection, pregabalin, gabapentin, duloxetine, or tricyclic antidepressants (TCAs) such as nortriptyline can be tried. If these fail, surgical decompression may be necessary.