Achilles tendon rupture

Background

Achilles tendon anatomy.

• Most frequently ruptures 2-6cm above calcaneus (where blood supply is weakest)
• Typical patient is 30-50yr old man who participates in strenuous activities on occasional basis
• Quinolone-associated rupture occurs in only 12 per 100,000 treatment episodes, and risk may be equivalent to oral steroids or non-quinolone antibiotics

Clinical Features

• Sudden, severe pain typically with rapid acceleration or pivoting
• May hear a "pop"
• Inability to run, stand on toes, or climb stairs
• Palpable defect in Achilles tendon 2-6cm proximal to calcaneus (SN 73% and SP 89% for partial tear)
• 20-30% of ruptures will have some amount of active plantar flexion or be able to walk

Differential Diagnosis

Calf pain

• Achilles tendon rupture
• Calcaneal bursitis
• Cellulitis
• Compartment syndrome
• Deep venous thrombosis (DVT)
• Distal leg fractures
• Gastrocnemius strain
• Ruptured popliteal cyst (Bakers cyst)
• Superficial thrombophlebitis

Evaluation

Workup

Achilles tendon rupture. No fracture on radiograph (left) with discontinuity of tendon over several centimeters (right; red line).

Ultrasound of achilles tendon rupture, long axis view

• Consider x-rays to rule out fracture
• Consider ultrasound in equivocal cases
  • Comparing to normal ankle can reveal smaller defects or tears

Thompson test

Positive Thompson test for left Achilles tendon rupture: no movement of the foot despite the calf being squeezed.

(SN 96% and SP 93%)

• Lay patient prone with knee bent at 90°
• In normal patient, squeezing calf results in plantar-flexion

Diagnosis

• Typically a clinical diagnosis (via positive Thompson test)

Management

• Rest, ice, elevation
• Non-weightbearing
• Short leg posterior splint with ankle slightly plantar-flexed
  • Walking boot can be used as well

Disposition

• Outpatient with ortho referral