Extensor carpi ulnaris tendinopathy

Dr Henry Knipe et al.

Extensor carpi ulnaris (ECU) tendinopathy is varied and includes tendinosis, (stenosing) tenosynovitis, tendon instability and rarely rupture. 

Athletes at increased risk of ECU tendinopathy include those who participate in 1,2:

  • racquet sports, e.g. tennis
  • club sports, e.g. golf
  • high-impact contact sports, e.g. rugby

Patients typically present with ulnar-sided wrist pain and/or pain on wrist extension. Localized swelling may be present. 

A positive ECU synergy test appears sensitive although not 100% specific for ECU tendinopathy. With the elbow in 90º flexion and the forearm in full supination, resistance to thumb abduction with counter pressure on the middle finger. Reproduction of dorsal-ulnar wrist pain is considered positive for ECU tendinopathy although the test may also be positive in triangular fibrocartilage complex or lunotriquetral pathology 1.

Numerous pathologies can affect the ECU tendon 2:

  • tenosynovitis
    • causes by repetitive wrist flexion/extension, especially in supination
    • in non-athletes, consider rheumatoid arthritis
    • stenosing tenosynovitis is rare
  • tendinosis
    • results from overuse
  • tendon instability
    • ranges from subluxation to gross dislocation
    • results from ECU subsheath injury/dysfunction
    • usually the result of single acute trauma

Ultrasound and MRI are the mainstays of ECU tendon imaging, with ultrasound offering the advantage of dynamic assessment, Doppler interrogation for inflammation and assessment of the contralateral ECU tendon 2

Other causes of ulnar-sided wrist pain should be considered such as 2,3:

  • triangular fibrocartilage complex injury
  • lunotriquetral ligament injury
  • distal radio-ulnar arthropathy
  • ulnar styloid fracture
  • ECU tendon sheath becomes more prominent distal to the ulnar styloid and should not be mistaken for tenosynovitis 2
Share article

Article information

rID: 65488
Synonyms or Alternate Spellings:
  • ECU rupture
  • Extensor carpi ulnaris rupture
  • ECU subluxation
  • Extensor carpi ulnaris subluxation
  • ECU stenosing tenosynovitis
  • Extensor carpi ulnaris stenosing tenosynovitis
  • ECU tenosynovitis
  • Extensor carpi ulnaris tenosynovitis
  • ECU tendinopathy

Support Radiopaedia and see fewer ads

Cases and figures

  • Axial images at l...
    Case 1: ECU tendinopathy and split tear
    Drag here to reorder.
  • Case 2: ECU subluxation
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.