Definition: Tear of the Achilles Tendon, most frequently 4-6 cm above calcaneal tendon insertion

Achilles Tendon Anatomy (


  • The Achilles tendon is the largest tendon in the body
  • It is formed by the convergence of the soleus muscle tendon and medial and lateral gastrocnemius tendons  (see figure 1 above)
  • This tendon receives blood supply from posterior tibial artery
  • Rupture usually occurs 4-6 cm above the calcaneal insertion in hypovascular region or “watershed/critical” zone


  • ~80% of these injuries occur as a traumatic injury during a sporting event (Leppilahti 1998)
  • May occur with
    • Sudden forced plantar flexion
    • Extreme dorsiflexion in a plantar flexed foot


  • Often misdiagnosed as an ankle sprain, and may be missed in up to 25% of cases
  • Incidence 18-29:100,000 per year, and is rising  (Chiodo 2006, Sheth 2017)
  • Risk factors:
    • Flouroquinolone antibiotics (particularly when used concomitantly with systemic steroids)
    • Steroid injections
    • Chronic inflammatory conditions (SLE, rheumatoid arthritis)
    • Episodic athletes, also known as “weekend warriors”
    • Most commonly in men aged 40-50 (Sheth 2017)


  • Patients may state they felt a “pop”
  • May have palpable gap or deformity in region of tendon

Achilles Tendon Rupture Exam (

Physical Exam

  • Weakness with plantar flexion
  • Increased resting ankle dorsiflexion on affected side in prone position with knees bent 
  • Palpable gap in dorsal portion of heel
  • Calf atrophy in chronic cases
  • Usually in absence of bony tenderness unless accompanied by other injury
  • Thompson Test (video)
    • Place the patient in the prone position, with feet hanging over the end of a stretcher or table. If patient is not able to lay down/there are no stretchers, the patient can kneel on a stool or chair
    • Squeeze the calf of the normal limb. You will notice the squeeze will cause the ankle to plantar flex appropriately
    • Squeeze the calf of the limb with the suspected Achilles tendon rupture.  You will notice the squeeze will cause no motion if there is a full rupture/tear, and diminished motion if there is a partial tear
    • Performance Characteristics (Garras 2012)



(+) LR

(-) LR






  • X-Rays
    • Used to rule out other or concurrent pathology
    • May show soft tissue swelling and destruction of pre-Achilles fat pad (Kager’s Fat Pad)
    • Findings are non-specific as tear of tendon unable to be visualized

Kager’s Fat Pad (

  • Ultrasound
    • Ultrasound is helpful if obvious findings present and to distinguish between partial vs complete tears, however only around 50% sensitive for detecting only partial tears (Kayser 2005)
    • Normal Achilles tendon . In the image below, you can visualize the intact tendon in between the two white crosses. You will notice there is no tear or surrounding edema/fluid

Case courtesy of Dr Maulik S Patel, From the case rID: 9759

  • Full thickness rupture of Achilles Tendon: The retracted tendon appears to the left, with an anechoic area representing a defect full of fluid adjacent to ruptured tendon (to the right, as labeled)

Case courtesy of Dr Maulik S Patel, From the case rID: 13548

  • Partial thickness rupture: In the image below there is a partial thickness tear indicated in between the white arrows. Partial tears show a more hypoechoic and thickened portion of the tendon as you near the tear, as seen to the right of the midline of the image

Partial Thickness Tear (

  • MRI
    • Gold-standard imaging modality
    • Rarely, if ever, necessary in the ED
    • Used for equivocal physical exam/alternate imaging findings or for assessing the severity of the tear for possible operative management
    • Findings
      • A full-thickness tear often shows a tendinous gap filled with edema or blood
      • Complete rupture shows retraction of tendon ends

Resting Equinus Position (

ED Management

  • Provide analgesia
  • Tendon stabilization in an optimal healing position
    • Functional bracing/splinting in resting equinus/talipus equinus
    • AO splint/brace in 20 degrees of plantar flexion for 4-6 weeks (may use tall CAM boot with 20 degrees wedge inserts)
    • All patients should be non-weightbearing
      • Any weight-bearing can convert a partial tear to a complete tear
      • Maintain non-weightbearing status until see orthopedics (within 1 week)
      • After evaluation by orthopedics, early weight-bearing and early ROM exercises yield better outcomes (can be as early as 2 weeks)
  • Referral to rehab warranted to improve plantar flexion and decrease risk of re-rupture
  • ED Ortho consultation: patients with open wounds in the area of trauma, or with concomitant fractures
  • Operative Management is usually reserved for acute ruptures (approximately <6 weeks) of full thickness with large tendon gaps, failed conservative treatment of partial thickness tears, or high performance athletes
    • These cases will be determined during follow up with orthopedics and may warrant outpatient MRI to assess severity of tear


  • For conservative management, there is no significant difference in plantar flexion strength (Willits, 2010)
  • Some increased risk of re-rupture compared to operative management, although review of evidence shows that this may not be significant if patients used structured, accelerated rehab protocol.
  • Protocol includes initially non-weightbearing cast with the foot in equinus position as described above, then transitioned to a pneumatic walker with elevated heels (elevation gradually reduced biweekly), and physical therapy to improve gait, strength, and mobility. (Wallace 2011)
  • If addressed early and appropriately, most patients have good self-reported long-term outcomes regardless of the treatment modality

Take Home Points

  • Achilles tendon rupture is a clinical diagnosis. The Thompson Test should be applied in all suspected cases
  • Remember to brace or splint a rupture, even if suspected, in the resting equinus position for optimal healing and prevention of further injury
  • Schedule follow up with orthopedics within 1 week for discussion of operative management vs early rehab protocols

Read More

Orthobullets: Achilles Tendon Rupture


Sheth U et al. The epidemiology and trends in management of acute Achilles tendon ruptures in Ontario, Canada: a population-based study of 27,607 patients. Bone Joint J. 2017; 99-B(1): 78-86. PMID: 28053261

Chiodo CP, Wilson MG. Current Concepts Review: Acute Ruptures of the Achilles Tendon. Foot Ankle Int 2006; 27(4): 305-13. PMID: 16624224

Leppilahti J, Orava S. Total Achilles tendon rupture. A review. Sports Med. 1998; 25(2): 79-100. PMID: 9519398 

Kayser R et al. Partial rupture of the proximal Achilles tendon: a differential diagnostic problem in ultrasound imaging. Br J Sports Med. 2005; 39(11): 838-42. PMID: 16244194

Margetic P et al. Comparison of ultrasonographic and intraoperative findings in Achilles tendon rupture. Coll Antropol. 2007; 31:279-284. PMID: 17598414

Garras DN et al.  MRI is Unnecessary for Diagnosing Acute Achilles Tendon Ruptures: Clinical Diagnostic Criteria. Clin Orthop Relat Res 2012; 470(8): 2268-2273. PMID: 22538958

Willits K et al. Operative versus nonoperative treatment of acute Achilles tendon ruptures: a multicenter randomized trial using accelerated functional rehabilitation .J Bone Joint Surg Am. 2010; 92(17): 2767-75. PMID: 21037028

Wallace RG et al. The non-operative functional management of patients with a rupture of the tendo Achillis leads to low rates of re-rupture. J Bone Joint Surg Br 2011; 93(10):1362-6. PMID: 21969435

Erickson BJ. Is Operative Treatment of Achilles Tendon Ruptures Superior to Nonoperative Treatment? Orthop J Sports Med. 2015; 3(4): PMID: 26665055