Achilles tendon rupture

The Achilles tendon attaches the converged soleus and gastrocnemius muscles to the calcaneus. Achilles tendon ruptures most often result from indirectly transmitted forces during physical activity and primarily affect men aged 30–50 years. Preexisting degenerative conditions and certain medications (e.g., fluoroquinolones) have been linked with an increased risk of Achilles tendon rupture. Symptoms include a sudden onset of sharp pain in the tendon at the back of the ankle, usually accompanied by a popping or snapping sound and/or sensation and a weakened ability or inability to plantar flex. Diagnosis is clinical and may be confirmed on ultrasound or MRI. Management options include conservative and surgical treatments. Surgery is associated with a lower risk of Achilles tendon re-rupture.

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

References:^[1]

Epidemiological data refers to the US, unless otherwise specified.

• Mechanism of injury ^[2][3]
  • Indirectly transmitted forces during physical activity (e.g., tennis, basketball)
  • Rarely, direct trauma or spontaneous rupture due to chronic Achilles tendinopathy or degenerative changes
• Risk factors ^[4]
  • Preexisting degenerative conditions
  • Poor physical conditioning ^[5]
  • Medications
    • Glucocorticoids, e.g., local injections, systemic
    • Fluoroquinolones ^[6]
    • Bisphosphonates
  • Diabetes
  • Achilles tendinopathy
  • Hyperparathyroidism
  • Renal failure

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

• Signs and symptoms ^[2]
  • Popping or snapping sound and/or sensation when the injury occurs
  • Sudden, severe pain in the posterior aspect of ankle and foot
  • Inability to bear weight
  • Weakened ability or inability to plantar flex the affected ankle
• Physical examination ^[2][5]
  • Calf swelling (e.g., hematoma)
  • Palpable interruption of the affected Achilles tendon
  • Matles test: With the patient prone and the knees flexed to 90°, observe the ankles.
    • Normal: both ankles at same angle
    • Rupture: increased dorsiflexion of the affected ankle
  • Thompson test: With the patient prone and feet off the end of the bed, squeeze the calf and observe the ankle.
    • Normal: passive plantar flexion
    • Rupture: absent passive plantar flexion

Normal plantar flexion does not rule out a suspected Achilles tendon tear. Always compare the symptomatic side with the uninjured side. ^[2]

Clinical evaluation ^[7]

Clinical diagnosis of Achilles tendon rupture is based on ≥ 2 of the following examination findings:

• Abnormal Thompson test
• Abnormal Matles test
• Decreased plantar flexion strength
• Palpable Achilles tendon gap

More than 20% of acute Achilles tendon ruptures are missed and subsequently become chronic ruptures. ^[8]

Imaging ^[2][9]

Consider imaging to confirm the diagnosis and/or exclude other suspected pathologies (e.g., fracture).

• Initial testing: x-ray
  • Mainly used to exclude suspected fractures
  • Potential findings include:
    • Opacification of the space anterior to the Achilles tendon
    • Thickening or irregular contour of Achilles tendon
• Confirmatory studies: ultrasound and/or MRI
  • Can distinguish partial- and full-thickness tears
  • Ultrasound findings include hypoechoic gaps between torn tendon fibers and/or hyperechoic hematoma.
  • MRI findings include heterogenous signal between torn tendon fibers and/or a fluid-filled gap in full-thickness rupture.

• Ankle fracture
• Ankle sprain
• Calcaneus fracture
• Retrocalcaneal bursitis
• Stress fracture
• Achilles tendinopathy
• Arthritis (e.g., osteoarthritis, gout, pseudogout, septic arthritis)

The differential diagnoses listed here are not exhaustive.

Achilles tendon ruptures may be managed conservatively or surgically; there is no consensus on which treatment modality is optimal. Treatment decisions are based on patient factors (e.g., age, comorbidities) and made in consultation with orthopedics. ^[2][7]

Initial management ^[2]

• Provide oral analgesia, e.g., acetaminophen, NSAIDs.
• Immobilize the affected foot in either of the following:
  • Walking boot with maximal heel lift
  • Splint with the foot in plantar flexion (e.g., in a posterior ankle splint)
• Establish non-weight-bearing status.
• Refer to orthopedics.

Conservative management ^[5][10][11]

• Initial immobilization in walking boot or cast for 3–4 weeks
• Serial casting with gradual reduction of plantar flexion for a further 4–8 weeks

Surgical management ^[7]

• Used with caution in patients with increased risk for surgical complications (e.g., diabetes, obesity, peripheral vascular disease, age ≥ 65 years)
• Operative techniques include open, limited open, and percutaneous tendon repair.

• Re-rupture: in ∼ 5% of individuals after surgical treatment and ∼ 10% of individuals after conservative treatment ^[12]
• Contractures and/or scarring → permanent limited range of motion

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

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