EXTENSOR CARPI ULNARIS TENDINOPATHY

Amanda Cooper

• Anatomy

• Biomechanics

• Injury Pathology

• Assessment

• Treatment

OVERVIEW

• Origin: − Middle third of the posterior border of

ulna − Lateral epicondyle of humerus

• Insertion: − Dorso-ulnar aspect of the base of the 5th

metacarpal

• Innervation: − Posterior interosseous nerve (C7 & C8), the

continuation of deep branch of radial nerve

• Main Action: − Wrist extension and ulnar deviation. It also

assists to provide stability at the wrist.

Anatomy

• Fibro-osseous tunnel – Distal ulna - ulnar groove – 1.5 to 2cm length band of connective tissue

(ECU subsheath)

• Stabilises the tendon at the level of the distal ulna

• ECU subsheath lies deep to the extensor retinaculum

• The overlying extensor retinaculum courses over the ECU and distal ulna to attach to the pisiform and triquetrum. Does not play a role in stabilising the ECU tendon.

• Linea jugata provides dynamic stability

Anatomy

• Linea Jugata

Anatomy

• Linea Jugata

Anatomy

• Shallow osseous groove

• Anomalous tendinous slips (EDM)

Anatomical Variations

• Pronation – Straight course

– Minimal force on subsheath

• Supination – ECU radially translates forming ulnar directed obtuse angle

– This angle is further increased with wrist flexion and ulnar deviation

– Maximal force on subsheath

Biomechanics

1. ECU Subluxation

2. ECU Tenosynovitis

3. ECU Rupture

Injury Pathology

• Associated Injuries / Differential Diagnosis – TFCC injury

– Lunotriquetral instability

– DRUJ injury

– Ulnar styloid non-union

Differential Diagnosis

• Requires an injury to the ECU subsheath

• ECU tendon is no longer maintained within its fibro-osseous groove

• Usually occurs as a result of acute injury – Forceful supination, flexion and ulnar deviation

• Tennis, golf, weight lifting, rodeo

• Cricket, forceful twisting of a drill

• Can develop into a chronic injury if left untreated

ECU Subluxation

Injury is classified into three groups: A. Stripping injury

B. Ulnar sided rupture of subsheath

C. Radial sided rupture of subsheath

ECU Subluxation

A. Stripping injury − ECU subsheath is stripped at its ulnar attachment, forming a false

pouch into which the ECU tendon can sublux (supination)

Stripping of subsheath at ulnar attachment resulting in subluxation during supination

Normal subsheath preventing subluxation

ECU Subluxation

B. Ulnar sided rupture of subsheath – Likely most common pattern of injury – Subluxes in supination with relocation of tendon upon pronation

C. Radial sided rupture of subsheath – Tendon is more likely to relocate lying above the ruptured subsheath. – Functional healing of the tendon is prevented

Supination Pronation

Ulnar sided rupture

Radial sided rupture

Relocates beneath ruptured subsheath

Relocates atop ruptured subsheath

ECU Subluxation

ECU Tenosynovitis & Tendinosis • Insidious onset

• Chronic stress is placed upon the tendon resulting in inflammation of its synovial lining, causing tenosynovitis – Office workers, Boiler maker, Chicken Treat

• Over time, stress may also lead to tendon degeneration and altered collagen content, resulting in tendinosis with or without partial tears.

• Second most common site of wrist tendinopathy in athletes – Racquet sports, golf, rowing

• Frequent early finding in patients with RA

• Blue arrow = fluid surrounding the ECU tendon

• Red asterisk = reactive marrow oedema

• Yellow asterisk = Normal ECU tendon

• Red arrow = ECU subsheath

• Blue arrow = extensor retinaculum

ECU Tenosynovitis & Tendinosis

T1 Weighted axial image STIR axial image

• Rare

• Characteristic cascade of events – Initial acute luxation event

– Low grade persistent pain (often with accompanying tenosynovitis)

– Local steroid injections (may have provided temporary relief)

– Increasing pain limits wrist activity, and subsequent imaging reveals the tendon rupture

• Decreased grip strength

ECU Rupture

• Tendon is absent

• Red arrow = subsheath is thickened

• Red arrowhead = chronically torn from radial aspect

ECU Rupture

• Location of pain &/or swelling – Dorso-ulnar wrist

• Onset of symptoms – Acute vs. gradual onset

• Mechanism of injury – Forceful supination, flexion, ulnar deviation

– Repetitive ulnar deviation

Assessment

• Tendon stability – Painful snapping or clicking sensation of the ECU tendon during

provocative testing • Active supination

• Passive supination

• Active supination, flexion and ulnar deviation

• MMT – Resisted wrist extension and ulnar deviation

– ECU synergy test (Ruland & Hogan 2008)

Clinical Assessment

1. Elbow flexed 90°; forearm in full supination; wrist neutral; fingers in full extension

2. Examiner grasps patients thumb and middle finger and palpates the ECU tendon with the other hand. The patient then abducts the thumb against resistance

3. Presence of both ECU and FCU muscle contraction is confirmed

4. Re-creation of pain along the dorsal ulnar aspect of the wrist is considered to be a positive test for ECU tendonitis

ECU Synergy Test

• MRI (supination)

• Dynamic ultrasound

(pronation & supination)

Imaging

• Rest

• NSAIDs

• Immobilisation (splinting or casting)

• Ergonomic assessment

• Activity modification

Conservative Management

• ECU Subluxation – Maintain forearm in pronation. Wrist in slight extension and radial

deviation

– 6-12 weeks

– Mixed results in literature

Conservative Management

• ECU Tenosynovitis – Ulnar gutter to prevent ulnar deviation

– Advise patient to avoid forearm rotation

– 3-6 weeks

Conservative Management

Activity Analysis & Modification

• Activity Analysis – Identification of tasks involving repetitive ulnar

deviation

– Ergonomic assessment

• Activity Modification – To enable the person to continue with activity

• Use other hand

• Alternative grip

• Assistive devices or equipment

Ergonomic Equipment

• Avoid ulnar deviation – Whale mouse: designed to promote a relaxed

hand position and neutral deviation at the wrist

– Split keyboard: maintains neutral alignment

• Indications: – ECU tenosynovitis/tendinosis who remain symptomatic despite

conservative treatment

– Torn subsheath ends widely separated

– Tendon lies outside the torn subsheath (radial sided tears)

– ECU rupture

Medical Management

• Corticosteroid injection (with caution)

Medical Management

• Surgery – Direct repair

– Subsheath reconstruction

• Radially based extensor retinacular flap

• Free retinacular graft

– Sulcus deepening

– Tenosynovectomy (+/- tendon debridement)

– Tendon graft from palmaris longus for ECU ruptures

Medical Management

• Immobilisation in extension & pronation for 4 weeks post surgery

Conclusion • Important to have an understanding of the different types of

injuries that can occur as this will affect your treatment plan – ECU subluxation versus ECU tenosynovitis

– Start by looking at the mechanism of injury

Conclusion • ECU subluxation

– Acute injury – forceful supination, flexion, ulnar deviation

– Focus is on limiting supination

– Sugar tong versus wrist gauntlet

– Need for further study into the effectiveness of splinting for ECU subluxation

• Does the location of the tear have an impact i.e. ulnar versus radial sided subsheath tears

• Importance of the linea jugata

Conclusion • ECU tenosynovitis

– Gradual onset – repetitive ulnar deviation

– Focus is limiting ulnar deviation

– Importance of OT role in activity analysis and modification.

– ECU synergy test

Thank you

Allende, C., Le Viet, D. (2005). Extensor Carpi Ulnaris Problems at the Wrist – Classification, Surgical Treatment and Results. Journal of Hand Surgery, 30B (3), 265-272. Inoue, G., Tamura, Y. (1998). Recurrent dislocation of the extensor carpi ulnaris tendon. British Journal of Sports Medicine, 32, 172-177. Jeantroux, J., Becce, F., Guerini, H., Montalvan, B., Le Viet, D., Drape, JL. (2011). Athletic injuries of the extensor carpi ulnaris subsheath: MRI findings and utility of gadolinium-enhanced fat-saturated T1-weighted sequences with wrist pronation and supination. European Society of Radiology, 21, 160-166.

Thomas, G.J. (2012). Pathologies of the Extensor Carpi Ulnaris (ECU) Tendon and its Investments in the Athlete. Hand Clinics, 28, 345-356. Patterson, S., Picconatto, W., Alexander, J., Johnson, R. (2011). Conservative Treatment of an Acute Traumatic Extensor Carpi Ulnaris Tendon Subluxation in a Collegiate Basketball Player: A Case Report. Journal of Athletic Training, 46(5), 574-576. McAuliffe, J. (2010). Tendon Disorders of the Hand and Wrist. Journal of Hand Surgery, 35A, 846-853. Ruland, R., Hogan, C. (2008). The ECU Synergy Test: An Aid to Diagnose ECU Tendonitis. Journal of Hand Surgery, 33A, 1777-1782.

References

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