Achilles tendon rupture !
An Achilles tendon rupture is a tear of the big tendon above the heel; it often feels like a kick to the calf and makes pushing off weak.
Updated 2026-10-29
Structures involved
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- Gastrocnemius (inner head)
- Gastrocnemius (outer head)
- Soleus
- Calcaneus
- Plantaris
- Heel bursae
- Sural nerves
- Flexor hallucis longus
- Tibial nerve
In the clinical exam
Why it happens
What it is
A partial or complete tear of the Achilles tendon, the common tendon of the gastrocnemius and soleus that inserts on the calcaneus, usually a few centimetres above the heel.
Who gets it
Typically affects middle-aged adults who play sport occasionally ("weekend athletes"), more often men. Football and racquet sports are common settings.
Causes
- Sudden push-off with the knee straight
- Unexpected forced dorsiflexion of the ankle
- Violent dorsiflexion of a plantar-flexed foot, e.g. a fall from height
Risk factors
- Pre-existing Achilles tendinopathy
- Fluoroquinolone antibiotics
- Systemic or local corticosteroids
- Intermittent sport without conditioning
- Older age and male sex
- Inflammatory and metabolic diseases (e.g. gout, chronic kidney disease)
Pathophysiology
The tendon's mid-portion has a relatively poor blood supply, a watershed area where degeneration builds up. A sudden eccentric load on a weakened tendon makes the fibres fail, most often 2–6 cm above the insertion. The torn ends can retract, and plantar flexion strength falls.
Classification
- Acute or chronic (missed, neglected) rupture
- Partial or complete
- By site: mid-substance, insertional, musculotendinous junction
Symptoms and signs
- Sudden pain in the back of the heel, often like being kicked or hit
- A pop or snap at the moment of injury
- Weak push-off; difficulty walking on tiptoe or climbing stairs
- Swelling and bruising above the heel
- A palpable gap in the tendon
Diagnosis
- Clinical
- Thompson test (squeezing the calf does not move the foot), palpable gap, increased resting dorsiflexion compared with the other side (Matles test). Clinical diagnosis is usually reliable.
- Tests
- Usually none.
- Imaging
- Ultrasound confirms the tear and measures the gap; MRI if unclear or chronic. X-ray excludes calcaneal avulsion.
Differential diagnosis
- Achilles tendinopathy or partial tear
- Medial gastrocnemius strain ("tennis leg")
- Plantaris rupture
- Deep vein thrombosis
- Calcaneal avulsion fracture
- Ankle fracture
Goal of treatment
Heal the tendon at the right length and tension to restore push-off strength, with the least re-rupture and complication risk.
Treatment
- Conservative
- Non-operative care: a boot or cast with the foot pointed down, then gradually brought up, with early functional rehabilitation.
- Surgical
- Surgical repair (open or minimally invasive) is often offered to active patients; it may lower re-rupture risk but adds wound and nerve risks. Evidence varies.
- Surgical
- Chronic ruptures may need reconstruction, for example a flexor hallucis longus tendon transfer.
- Rehabilitation
- Structured rehabilitation for range of motion, calf strength and return to sport over months.
Complications
- Re-rupture
- Tendon healing elongated, with weak push-off
- Wound infection or breakdown after surgery
- Sural nerve injury
- Deep vein thrombosis during immobilisation
Prognosis
Most patients return to walking and many to sport, but full recovery takes months and some calf weakness may persist.
Prevention
- Gradual conditioning before sport
- Caution with fluoroquinolones and corticosteroids, especially in older adults
Test yourself
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How is the Thompson test performed and what is a positive result?
With the patient prone, the examiner squeezes the calf. In a complete rupture the foot does not plantar-flex.
Where does the Achilles tendon usually rupture?
In the relatively poorly perfused mid-portion, roughly 2–6 cm above its insertion on the calcaneus.
Which antibiotic class is associated with Achilles tendon rupture?
Fluoroquinolones, especially in older adults and with corticosteroid use.
Why can a patient with a complete rupture still plantar-flex the foot weakly?
Other muscles (tibialis posterior, long toe flexors, fibularis muscles) can still plantar-flex, which can mask the diagnosis.
Related conditions
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Achilles Tendon Rupture (StatPearls (NCBI Bookshelf), 2023).
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