Subluxation ECU

Anatomy

 

6th compartment

- fibro-osseous tunnel overlying 1.5 cm to 2.0 cm of distal ulna

- held tight by the extensor carpi ulnaris tendon sheath

- the extensor retinaculum passes around the ulna to insert on the palmar aspect of the carpus

- extensor retinaculum is a separate structure from the ECU tendon sheath

 

Mechanism

 

Forced supination, palmar flexion, and ulnar deviation

- ECU tendon can rupture or attenuate the extensor carpi ulnaris tendon sheath

- dislocate in a palmar and ulnar direction

- the tendon relocates on forearm pronation

 

Most common in tennis players

 

Symptoms

 

Clicking or snapping of ECU with rotation

- may cause pain

 

Tends to dislocated dorsally with supination

 

Management

 

Acute cases

 

Immobilization in a long-arm plaster splint in pronation 

 

Chronic cases

 

Operative reconstruction of the extensor carpi ulnaris tendon sheath

- using extensor retinaculum