Management and Outcomes
ECU Tendinosis
Acute tendinosis of the ECU usually responds to non-operative measures of rest, activity modification, splintage (in a position of 30° wrist extension and ulnar deviation) or, occasionally, immobilisation in a short-arm plaster cast in the same position for a 3-week period.
Some prefer to rest the wrist in a long-arm cast with the forearm in pronation, so that the ECU tendon sits comfortably located within the dorsal ulnar groove. There is no evidence to support one type of cast over another.
Rehabilitation strategies are based on the severity of tendinopathy. Treatment of the early reactive phase consists of load management and isometric exercises until the pain settles (typically over 5–10 days). Load can then be increased in stages. Ibuprofen is thought to be a helpful adjunct during this phase.
In chronic tendinopathy, without a sudden increase in pain, a combination of load management, eccentric work, isometrics and strength exercises are likely to help. Some of the changes within the tendon may be reversible but it is likely this is a condition that will need to be managed in the long term.
If symptoms are not relieved by non-operative measures an injection of steroid into the fibro-osseous sheath should be considered. A preliminary injection of local anaesthetic can be used for diagnostic confirmation and also as a mechanical hydrodissector to create space within the sheath for subsequent steroid injection.
Injections are best performed under US guidance; to ensure accurate placement of injectate and to avoid intratendinous injection (and risk of precipitating subsequent rupture).
In patients with persistent ECU tendinosis, cocompartment release should be considered. This involves division of the intercompartmental septum between the fifth and sixth extensor compartments, hence increasing the compartmental volume without threatening its stabilising function.
Return to athletic activity should be based on rehabilitation goals of range of motion and strength. These should ideally reach 80% of the uninjured side before returning to sports.
ECU Instability
Asymptomatic subluxation of the ECU tendon does not always require treatment. However, in cases of tendon instability associated with secondary tendinosis, conservative management of the tendinosis alone is unlikely to be successful.
Early diagnosis of an acute traumatic unstable ECU tendon may be managed by reduction of the subluxed tendon and immobilisation for a period of up to 6 weeks. Reduction is achieved by positioning the wrist in radial deviation and the forearm in pronation. The tendon will relocate into the ulnar groove and should then be maintained in this position by application of a long-arm cast. A report of 28 professional tennis players demonstrated successful outcome in all cases of tendon instability when treated with a prolonged period of immobilisation of up to 4 months. This prolonged immobilisation regime obviously has an impact on athletic conditioning and performance and may not be favoured in some circumstances.
In chronic subluxation surgical reconstruction of the sixth extensor compartment may be indicated, particularly in an elite athlete. Different techniques have been reported using a sling created from the remaining extensor retinaculum. These type of reconstructions are termed 'non-anatomic' because they do not recreate the normal anatomy of the ECU complex. The repair must not be too tight to prevent smooth gliding of the newly stabilised tendon with wrist movement.
Anatomic reconstructions are indicated when the periosteum and tendon sheath strip off the distal ulna and the tendon subluxes within an expanded subsheath. The subsheath is reattachment on the ulnar groove with a series of small bone anchors. Twenty of 21 patients treated in this way, at an average of 17 months after injury, returned to their previous sport or employment with no reports of recurrent subluxation.