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Extensor Carpi Ulnaris Tenosynovitis Pilot Study

A pilot study undertaken by the Merivale Hand Clinic in conjunction with Ram Chandru (Orthopaedic Hand and Wrist Surgeon)

The extensor carpi ulnaris (ECU) muscle plays an important role in wrist movement and also provides stability to the outer side of the wrist.

ECU tendonitis is the result of inflammation of the ECU tendon. This condition is most common in non-athletes, however ECU injuries frequently occur in tennis, golf and the rugby codes. Raphael Nadal is probably the best known tennis player to succumb to ECU tendonitis, withdrawing from both the French Open and Wimbledon in 2016 due to injury. The ECU tendon sheath can be irritated and become inflamed by repetitive forward and backwards movement of the wrist, or when the tendon is put under excessive load. This results in pain with gripping and twisting movements of the wrist e.g. opening bottles.

Signs and symptoms of ECU tendonitis include:

  • Tenderness directly over the ECU tendon
  • Swelling or fullness of the tendon sheath
  • Pain with twisting movements e.g. opening doors, opening jars or bottles

This pilot study was undertaken to establish whether a corticosteroid injection (CSI) followed by three weeks immobilisation in a cast and hand therapy improves day-to-day function and reduces the patient experience of pain in ECU tendinopathy.

Figure 1.0 ECU tendon (in yellow) passing through a tunnel with the wrist in pronation Figure 1.1 A glum Raphael Nadal announcing his withdrawal from the French Open in 2016.

The study was limited to those patients with ECU tendon inflammation only. Following assessment, a corticosteroid injection was administered to the ECU tendon sheath by the surgeon. Following this, the affected wrist was immobilised in a cast for 3 weeks. After this time a removable splint was used for a further 3 weeks and wrist exercises were started.

Figure 1.2. Removable splint

Measures were taken initially at 6 weeks post injection, 12 weeks post injection and finally at 6 months post injection.


  • 17 participants were included in this study. Of those, 41% were male and 59% were female.
  • The average age of participants was 37 years (range 21 – 70 years old).
  • The average time from injury to corticosteroid injection was 15 weeks (range 6 – 58 weeks).
  • 88% of participants were right hand dominant. 6% were left hand dominant and 6% were ambidextrous.
  • Two thirds of participants injured their dominant hand.
  • Results were best demonstrated by outcomes from the QuickDASH questionnaire (Disability of the Arm, Shoulder and Hand). This questionnaire (which assesses a person’s symptoms and their ability to manage certain activities) is scored out of 100. A higher score indicates greater difficulty doing daily tasks. A score of zero indicates normal daily function. The trend shown by the QuickDASH for this study showed significant improvement for most participants.
  • QuickDASH score improved on average by 33 points.

Results of this pilot study seem to indicate that a CSI followed by three weeks immobilisation in a Muenster cast and with hand therapy input improves a patient’s functional abilities and reduces the experience of pain in ECU tendinopathy.

Clinically this result reflects what is being seen in our hand therapy clinics. All patients followed up were pleased they had received the CSI and subsequent plaster immobilisation of the wrist and forearm. In fact, results have encouraged us to use the same treatment approach for patients experiencing other common conditions involving tendonitis, especially those conditions that are severe and not settling with simple splinting alone.

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