ECU Subluxation: Symptoms, Causes & Treatment

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The ECU tendon sheath can be irritated by repetitive flexion and extension of the wrist. Repetitive sporting activities often lead to the development of tenosynovitis.

Tendinopathy is thought to be an adaptive response of the tendon to repetitive stress and/or trauma and may progress through different stages –  reactive tendinopathy, tendon disrepair and degenerative tendinopathy.

Tendon instability can vary from minor subluxation of ECU during rotational movements to dislocation and forearm locking.

Then you can have disruption of the subsheath of the ECU – this means the tendon doesn’t sit in its natural groove. This type of condition is commonly associated with sports such as rugby, football and water polo.

The ECU is important for wrist extension and ulnar deviation, but also in providing stability to the ulnar side of the wrists. Its position changes with forearm supination and pronation, therefore it needs to be mobile, yet stable.

The ECU synergy test is useful to detect tendinitis, whereas with active contraction of the ECU you can observe the snapping of the tendon as it leaves the groove.


Conservative treatment:

  • Munster splint to prevent forearm rotation = rest
  • load management and isometric exercises
  • US guided cortisone injection
  • Surgery is mainly required if major instability is present.

Very rarely will an operation be conducted for tenosynovitis itself, as this does tend to resolve with conservative treatment and nothing structurally that needs changing.

Surgery repositions the ECU sub-sheath more radially to avoid it subluxing ulnar and volar during supination.

If you are suffering from ECU Subluxation and would like it examined by one of our fully qualified therapists, please call us at Melbourne Hand Therapy today (03) 9899 8490 or leave an enquiry and we will get back to you as soon as possible.

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