distal intersection syndrome
The distal intersection syndrome relates to tenosynovitis of the extensor pollicis longus (EPL) tendon (3 extensor compartment), where it crosses the extensor carpi radialis longus (ECRL) and brevis (ECRB) tendons (2 extensor compartment) . It is distinct from intersection syndrome which occurs more proximally in the forearm at the intersection of the first and second extensor compartments.
Anatomy
The crossing of the second extensor compartment is typically located just distal to Lister’s tubercle. The tendon sheaths of the EPL and the ECRB are connected by a communicating foramen . This is probably why inflammation of the EPL tendon spreads to the second compartment or vice versa.
Clinical presentation
Pain and swelling over Lister’s tubercle. Less commonly, local crepitus during thumb movements.
Pathology
Etiology
Various mechanisms, including:
- attrition is related to a biomechanical pulley effect by Lister’s tubercle (overuse syndrome)
- direct blunt trauma of the EPL tendon
- distal (not necessarily displaced) radius fracture
Trauma is the most frequent cause. EPL tenosynovitis usually occurs within 8 weeks, but can still be found years after an injury.
Risk factors
- rheumatoid arthritis
- systemic lupus erythematosus
- gout
- degenerative carpal joint disease
Radiographic features
Ultrasound
May show peritendinous edema and fluid within the tendon sheaths at the intersection point between the 2 and 3 dorsal extensor tendon compartments .
MRI
Typically shows features of peritendinous edema (peritendinitis) around the 2 and 3 extensor compartment tendons, extending proximally from the crossover point of the EPL in the dorsal wrist.
Treatment and prognosis
An early operative release is advocated due to a high risk of EPL tendon rupture (drummer boy’s palsy) .
Differential diagnosis
On imaging consider:
Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu EPL tenosynovitis: