Summary

The Achilles tendon is the largest tendon in the human body and provides the attachment of the converged soleus and gastrocnemius muscles to the calcaneus. Achilles tendon ruptures often result from indirect trauma related to sports and exercise and primarily affect men between the ages of 30–50 years. Pre-existing degenerative conditions and certain drugs (e.g., local glucocorticoid injections) have been linked with an increased risk of complete or partial Achilles tendon rupture. Patients may experience a sudden onset of sharp pain in the tendon at the back of the ankle, usually accompanied by a popping or snapping sound or sensation. A positive Thompsons test may be followed by an ultrasound or MRI to confirm the Achilles tendon rupture. Both conservative and surgical treatments are recommended. Surgical treatment is associated with a lower risk of Achilles tendon re-rupture. However, complications linked to surgery, such as infection and hemorrhage, must be taken into consideration.

Epidemiology

Peak incidence: 30–50 years
Sex: ♂ > ♀
Most common in people that are active in sports or recreational activity

References:^[1]^[2]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

Anatomy of the Achilles tendon
- Largest tendon in the human body
- Provides the attachment of the converged soleus and gastrocnemius muscles to the calcaneus
Mechanism of injury
1. Indirect trauma from physical activities (e.g., tennis, basketball)
2. Rarely, direct trauma or longstanding paratenonitis (possibly with tendinosis)
Risk factors
- Pre-existing degenerative conditions (including polyarthritis)
- ↓ Physical conditioning (poor physical condition)
- Medication
  - Local injections of glucocorticoids
  - Systemic glucocorticoids
  - Immunosuppressants

References:^[3]

Classification

Complete rupture (most common)
Less common:
- Partial rupture
- Avulsion of the bony insertion of the Achilles tendon at the calcaneus

Clinical features

Popping or snapping sound/sensation when the injury occurs
Sudden, severe pain in the Achilles tendon
Difficulty mobilizing: loss of plantar flexion power on the affected side
Deformity: calf swelling; (e.g., hematoma) and/or palpable interruption of the affected Achille's tendon
Clinical test
- Thompson test: squeezing the calf (e.g., gastrocnemius muscle) of the patient, in prone position with legs extended
  - Normal: results in passive plantar flexion
  - Rupture: absent passive plantar flexion

Normal plantar flexion does not rule out a suspected Achille's tendon tear!
Always compare the symptomatic side with the opposite normal side!

References:^[3]^[1]

Diagnostics

Mainly a clinical diagnosis
Imaging is indicated to evaluate the extent of the injury and/or to exclude other suspected pathologies.
- Ultrasound (best initial test)
- X-ray: mainly to rule out suspected bone fractures
- MRI (confirmatory test): only imaging modality that can distinguish between a partial and complete rupture

References:^[4]

Treatment

Both conservative and surgical approaches are recommended, but the indications for conservative vs surgical treatment are controversial.

Conservative therapy
1. Rest, analgesia, serial casting
2. Rehabilitation
Surgical therapy
1. Open or percutaneous tendon repair
2. Casting
3. Rehabilitation

References:^[3]^[5]

Complications

Re-rupture
Contractures and/or scarring → permanent limited range of motion

References:^[3]

We list the most important complications. The selection is not exhaustive.

Prognosis

Excellent prognosis with early treatment
Repair of complicated cases (e.g., following re-rupture) has a poorer outcome.

References:^[3]