The intersection syndrome is a rare, special form of tendonitis, located at the junction of the first and second tendon compartment.
On the thumb side of the back of the hand, the abductor pollicis longus and the extensor pollicis brevis extend below the extensor retinaculum in the first tendon, crossing the extensor carpi radialis brevis and the extensor carpi radialis longus muscle in the second tendon.
Like most handheld tendinaginous syndromes, the syndrome is associated with frequent and repetitive movements of the wrist. Therefore, the syndrome occurs more frequently in athletes, especially those involved as rowers and weightlifters.
Clinically, a tender painful swelling 2 cm proximal to the tabatière, in severe cases with redness and crepitus. Pain occurs when stretching the wrist against resistance. Often there is a positive Finkelstein test (pain with a maximum thumb in the fist and passive passive ulnar abduction in the wrist).
The most important differential diagnosis is thought to be a Tendovaginitis de Quervain. The primary treatment of choice is a conservative therapy trial with short-term immobilization in functional position and a systemic anti-inflammatory therapy, additively, a local cortisone injection can be performed.
In the case of unsuccessful conservative treatment, surgical treatment (splitting of the second tendon and local synovectomy) may become necessary with the aim of allowing the tendon to glide freely.