June 15, 2021 7 min read

Answer a fun quick question about ECU tendinopathy, learn more about what defines this condition and find some helpful tips on the best hand therapy treatment.

Answer this Quick Question

Which of the following may be the cause of ulnar sided wrist pain;

  1. ECU tenosynovitis
  2. TFCC sprain
  3. Lunotriquetral ligament tear
  4. All of the above

Answer: d) All of the above


ECU Tendinopathy Defined

Definition: ECU tendinopathy is, as the name suggests, pathology of the Extensor Carpi Ulnaris (ECU) tendon and / or its sheath / subsheath in the sixth dorsal compartment of the wrist. There is some discussion in the literature as to whether it is just the tendon / sheath or indeed the edge of the pulley (extensor retinaculum) itself.

Anatomy:ECU originates from the lateral epicondyle of the humerus and inserts into the base of the 5th metacarpal. It lies in the sixth dorsal wrist compartment, which is the most ulnar one. The extensor retinaculum sits across the dorsum of the wrist and divides the extensor tendons into different compartments. The extensor retinaculum acts as a pulley and stops the tendon from bowstringing, holding it close to the bone over the ulnar styloid groove. As its name suggests, the ECU tendon extends the wrist in an ulnarward direction.


ECU tendinopathy

Pathomechanics:  When the forearm is in full supination, the ECU tendon sits quite dorsally, whereas in full pronation, it moves more ulnarward (lying in the ulnar groove, it moves as the ulnar rotates). Tension on the extensor retinaculum and subsheath is greater during activities performed in full supination. Tension is even greater when the movement includes wrist flexion and ulnar deviation. Usually, ECU tenosynovitis arises when there is repeated stress to this area of the wrist, from repetitively performing an activity requiring wrist flexion/extension (particularly in supination, and often with ulnar deviation). Repetitive friction of the tendon under the pulley results in the pulley and or tendon/sheath becoming inflamed. The more inflamed these structures become, the more they swell, which in turn increases the friction / irritation, so it becomes a vicious cycle.

There may be associated underlying tendinopathy. Reactive tendinopathy may be the result of forceful loading or direct trauma. The tendon remains structurally intact, but thickens and becomes stiffer. Tendon disrepair may occur with ongoing excessive loading – the structure of tendon itself begins to change, with greater matrix breakdown, increased vascularity and neuronal ingrowth. Degenerative tendinopathy is more common in older athletes due to chronic overloading. The tendon no longer efficiently adapts to load, thus collagen becomes progressively disorganised, with advanced matrix breakdown, which can lead to partial tear and rupture.

Clinical signs and symptoms: Clients will usually present reporting pain at the ulnar side of the wrist, most often over the ulnar styloid. It is painful with movement of the wrist and the sixth dorsal wrist compartment is usually tender to palpate over or just distal / proximal to the ulnar styloid. There may be swelling / redness / heat (not always present). If there is instability or injury to the supporting subsheath, the client may often report a snapping or popping sensation over the ulnar groove when they rotate the forearm.

Possible risk factors: ECU tenosynovitis, tendinopathy or instability may be sports related (e.g. tennis, golf, rugby), and players are more at risk if there is already some instability. Sometimes it is as the result of one acute sharp wrist flicking movement, or even as the result of a direct blow to the ulnar styloid. ECU tenosynovitis is also commonly seen in those with Rheumatoid Arthritis. Instability can occur when there is disruption of the supporting structures (ECU subsheath). This most commonly occurs when moving between pronation and supination, with the wrist flexed and ulnar deviated (think tennis, golf, rugby).

Clinical tests:

ECU synergy test: The client’s elbow is resting on the table, with forearm fully supinated and elbow at 90deg flexion, wrist neutral and fingers fully extended. Hand therapist holds the client’s thumb and long finger with one hand, while palpating the ECU tendon over the ulnar styloid with the other. The client then tries to extend his / her thumb against the therapist’s resistance. A positive test is when their pain is reproduced over the ECU tendon at the ulnar aspect of the wrist.

Observation and palpation: look for swelling / redness / heat (not always present) and palpate for tenderness over the ECU tendon at the level of the ulnar styloid. Sometimes the muscle belly itself is also TOP. When the tendon is subluxing, you may be able to palpate the snapping of the tendon as it pops out of the ulnar groove.

Imaging: X-rays will not usually be of benefit as they do not show the soft tissue structures. Ultrasound scans can give quick and accurate results, as they will show thickening to the tendon / sheath, increased vascularity, inflammation of structures, etc, and dynamic USS may be able to demonstrate if there is some instability.

Hand Therapy for ECU Tendinopathy

The goal of hand therapy for these clients is pain free return to full function. The focus of hand therapy is splinting, anti-inflammatory modalities, education and activity modification, followed by strengthening once acute symptoms have settled.


Splinting the wrist in 30deg extension and slight ulnar deviation appears to be the most useful. This can be achieved by a below elbow splint or cast. Some clinicians prefer to use an above elbow cast / splint, keeping the forearm fully pronated, so that the ECU rests comfortably in the ECU ulnar groove, although there is no strong evidence to prove that this is any more beneficial, and is certainly less functional for the client. Your splint selection should be based on severity, exacerbating activities, lifestyle, timeframes, etc.


Clients who understand the anatomy and biomechanics associated with their condition are more likely to understand how certain activities and / or positions /movements can exacerbate their symptoms. This makes it easier to understand how to modify activities, to prevent ongoing exacerbation of symptoms.  

Here are my top 3 hand therapy techniques for ECU tendinopathy:

  1. Splinting.As mentioned above, your splint selection should be based on severity, exacerbating activities, lifestyle, timeframes, etc. In acute presentations of tendinosis or ECU tenosynovitis, symptoms should start to settle within a week of below elbow splinting (which may be assisted by NSAIDs if your client can tolerate them). An off the shelf option may be sufficient, such as the Jura Black Wrist Brace or for something slightly longer and streamlined, try the Latex Free Wrist Brace Long. Once symptoms are settling well and only a light support is required, or to assist with a return to sport / work, an excellent choice is the Juraprene Short Wrist Wrap Universal 
  1. Education / activity modification. Clients need to understand the anatomy and bio/pathomechanics of this condition, so that they can easily learn to modify activities so prevent symptom exacerbation. They should avoid or modify activities demanding repetitive wrist extension, or for those with an instability, avoid pronation / supination with wrist flexed and ulnar deviated (i.e. where the ECU is most unstable). Wearing a splint can really help the client to understand what activities are using the provocative positions / movements.  
  1. Anti-inflammatory modalities. I like to use acupuncture for its anti-inflammatory effects. If this is part of your hand therapy toolkit (and your client is willing!), by all means try it! You may like to use ice and gentle STM with a topical anti-inflammatory cream. In the subacute and later stages, many clients find heat more soothing. I also advise the client to discuss with their doctor or pharmacist regarding anti-inflammatory medication, as these together with splinting provides the best outcome.


You could also try:

  1. Gentle stretching of the wrist and thumb, starting in the pain free range can really help. When the wrist and thumb are splinted 24/7 for 6 weeks, the structures can become very tight, so to prevent this your client should remove their splint and gently stretch several times per day (but again, stressing the PAIN FREE RANGE). It is often easier to achieve a comfortable stretch after heat and massage.
  1. Strengthening / loading. Soft tissues do not like to be immobilised for long periods. Having the wrist splinted 24/7 may result in weakening and poor organisation of the collagen fibres and increased cross linking between fibres. Isometric loading can very effectively prevent or reverse these effects, and because the loading is isometric it does not cause further friction / irritation of the inflamed soft tissues. It is important, however, that the loading not place more strain on an already irritated retinaculum, or in a position of instability. I get clients to work in pronation, resist wrist extension into ulnar deviation, loading only to a point of about 2/10 discomfort, then holding that position for up to 20 seconds or until the discomfort dissipates. (This is based on Mulligan Pain Relief Phenomenon exercises). Once they can perform these pain free, you can begin eccentric loading and then progress further, to sports specific strengthening.  
  1. Corticosteroid injection.In 75% of cases, these clients settle with full time splinting and NSAIDs. If this is unsuccessful after ~6/52, CSI could be considered as about 98% settle with corticosteroid injection into the sixth dorsal wrist compartment. I usually refer clients on to a specialist to have this administered with or without ultrasound guidance. I advise the client to go back into their splint for 7-10 days post-CSI and then get them back to Hand Therapy, to commence the isometric loading program, to ensure benefits are long lasting.

[It is worth noting that about 2% are unsuccessful with these modalities and may need to proceed to surgical intercompartmental release / decompression. Post-operatively I would undertake wound cares, scar management, early pain free AROM and isometric loading. They may or may not continue with intermittent splint use, depending on surgeon’s protocols / preference].


Suitable supports

My professional favourite for ECU tendinosis / tenosynovitis is the Jura Black Wrist Brace

View our full range of wrist supports

We have an excellent range of wrist supports that may be suitable for your clients.

What are your tips for treating ECU tendinosis / tenosynovitis?

This blog is a discussion format. We have listed our views above but would love to know what you think, what your comments are or how you best treat ECU tendinosis / tenosynovitis in your practice. Feel free to email us at info@therapyproductsaustralia.com