Extensor Hallucis Longus Tear: EHL Tendon Rupture Diagnosis and Surgical Repair

Extensor hallucis longus (EHL) tendon tear is an injury to the primary extensor of the great toe — the tendon responsible for lifting the great toe during walking, running, and toe clearance during swing phase. EHL ruptures are less common than Achilles or peroneal tendon injuries but produce a recognizable clinical picture: inability to extend the great toe against resistance, a palpable gap or soft tissue mass at the dorsal ankle or midfoot, and a characteristically dropped great toe during walking. EHL tears occur either from acute lacerations (the most common cause — the dorsal foot is vulnerable to crush injuries and puncture wounds that directly cut the tendon), direct contusion, or rarely from degenerative attrition at the extensor retinaculum. Diagnosis is clinical with MRI confirmation, and treatment ranges from splinting for incomplete tears to primary repair or tendon transfer for complete ruptures, with excellent functional results when treated appropriately.

EHL Tendon Tear: Anatomy, Mechanisms, and Clinical Assessment

Category	Details
Anatomy	Origin: middle fibula and interosseous membrane, anterior compartment. Course: anterior compartment → under extensor retinaculum between tibialis anterior (medially) and EDL (laterally) → inserts on dorsal base of distal phalanx of great toe. Function: primary great toe dorsiflexion (MTP and IP joints); assists ankle dorsiflexion; assists midfoot inversion. EHL provides ~20% of total ankle dorsiflexion; tibialis anterior provides 80%.
Injury mechanisms	Laceration (most common): dorsal foot lacerations from machinery, lawn mowers, glass, knives; tendon visible in wound or palpable gap confirms diagnosis. Contusion/crush: heavy object impact on dorsal foot at extensor retinaculum. Degenerative: rare spontaneous rupture at retinaculum crossing in elderly; similar to tibialis anterior pattern. Closed avulsion: forced plantarflexion under load (rare — usually at IP joint insertion = mallet toe equivalent).
Clinical presentation	Complete rupture: great toe lies in plantarflexion at rest; patient cannot extend great toe actively; palpable gap at injury site; visible retraction of proximal tendon end. Partial tear: great toe extension weakened but possible against some resistance; tenderness + swelling at tear site. Laceration: open wound + inability to extend = confirmed; surgical exploration mandatory — never assume tendon intact with open dorsal foot wound without direct exploration or imaging.
Functional significance of complete EHL loss	Great toe drops into plantarflexion during swing phase → catches on ground → increased trip/fall risk. Ankle dorsiflexion modestly reduced (EHL contribution ~20%). Walking on level ground generally managed with compensatory strategies if no repair. Stairs and uneven terrain: more problematic. Running: significant limitation — toe push-off impaired. IP joint plantarflexion deformity develops over time if not corrected (chronic dropped great toe).
Imaging	Ultrasound: dynamic assessment of tendon continuity; identifies gap, partial vs. complete, fluid in tendon sheath; operator-dependent but excellent for EHL given superficial location. MRI: complete tendon characterization — gap measurement, tendon stump location, tissue quality, associated injuries (adjacent tendons, bone, ligament in crush injury). Preferred for surgical planning in closed injuries or when tendon gap location uncertain.
Associated injuries	Laceration: check all structures in wound (tibialis anterior, EDL, dorsal neurovascular bundle — dorsalis pedis artery, deep peroneal nerve sensory branch). Crush: 1st and 2nd metatarsal fractures; cuneiform fractures; EHL and EDL simultaneous injury. Any open dorsal foot wound with mechanism to cut tendon: surgical exploration required — cannot be excluded clinically in open wounds.

EHL Tendon Tear: Treatment by Injury Type and Outcomes

Treatment	Indications	Technique / Protocol	Expected Outcome
Conservative (splinting)	Partial EHL tear (<50% tendon cross-section on imaging); complete tear in elderly sedentary patient; patient unwilling or unfit for surgery.	Short leg cast or CAM boot in neutral to slight toe extension 4-6 weeks. IP joint extension splinting for distal avulsion. PT after immobilization: active range of motion, progressive great toe extension strengthening.	Partial tears: 70-80% satisfactory function with conservative management; fibrous healing of partial tear allows continued extension function. Complete tear non-operative: great toe remains dropped; AFO toe plate prevents toe drag during walking; functional compromise permanent.
Primary repair (acute complete tear)	Complete EHL rupture within 4-6 weeks of injury; good tissue quality; active patient. Lacerations: repair at same operative session as wound debridement (ideally within 12-24 hours of injury).	Longitudinal dorsal incision; identify proximal and distal stumps; resect degenerative or contaminated tissue; repair with 3-0 or 4-0 non-absorbable running suture (modified Kessler core + running epitendinous); boot immobilization 6 weeks in neutral.	Excellent results in 85-90% with early primary repair; full great toe extension recovery at 3-4 months; return to sport 4-6 months. Best results with acute repair vs. delayed.
Reconstruction — EHL to EHB transfer	Chronic complete EHL tear (>6 weeks) with retraction; gap >3cm; poor native tissue quality; failed primary repair.	Extensor hallucis brevis (EHB) transfer: EHB harvested from lateral dorsal foot, rerouted to base of distal phalanx or proximal phalanx of great toe, secured to provide active toe extension. EHB is shorter and weaker than EHL but adequate for functional great toe extension. Interpositional autograft (plantaris) or allograft for gap bridging in appropriate patients.	EHB transfer: 75-85% functional great toe extension recovery; good for daily activities and most sports; patient satisfaction high.
Postoperative protocol (surgery)	All surgically treated EHL tears.	Non-weightbearing boot 2 weeks (wound healing); progressive weightbearing boot 4-6 weeks; PT at 6 weeks — passive then active great toe extension; return to normal shoe 8-10 weeks; return to sport 4-6 months.	Full great toe extension recovery expected with repaired or reconstructed EHL; strengthening 3-6 months post-op for complete return to sport.

At Balance Foot & Ankle in Howell and Bloomfield Township, any open dorsal foot laceration with inability to extend the great toe undergoes urgent surgical exploration — the EHL tendon cannot be confidently assessed as intact without direct visualization or MRI in open wounds, and delayed repair of a divided tendon beyond 2-3 weeks significantly increases reconstruction complexity due to tendon retraction and adhesion formation. Call (810) 206-1402.

For a complete clinical overview: Ankle Pain Conditions Guide — location-by-location ankle pain diagnosis and treatment

More questions patients ask

What causes an extensor hallucis longus tear?

EHL tears are caused by: direct laceration (most common — from lawn mower injuries, sharp objects), forced plantarflexion under load (suddenly catching the toe), and chronic tendinopathy with eventual rupture (rare). Laceration injuries must be repaired urgently to prevent retraction of the tendon ends. Closed ruptures from forced plantarflexion are less common but are the type most often missed on initial evaluation.

How is an EHL tear treated?

Partial tears (less than 50% of tendon thickness) are treated with immobilization in a boot with slight dorsiflexion for 6 weeks, followed by physical therapy. Complete ruptures require surgical repair — direct end-to-end repair within 2–3 weeks, or tendon grafting/transfer if presentation is delayed. Untreated complete EHL ruptures leave the big toe unable to lift (dropfoot of the hallux), causing tripping and shoe fit problems.

How long is recovery after EHL repair?

After surgical EHL repair: non-weight-bearing cast for 4 weeks, protected weight-bearing in a boot for 4 more weeks, then progressive return to activity. Full recovery to running and sport takes 4–6 months. The repair success rate is high when performed within the first few weeks of injury. Delayed repair requires more complex reconstruction with longer recovery.

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