Achilles Tendon Injuries Workup

Updated: Sep 15, 2022
  • Author: Anthony J Saglimbeni, MD; Chief Editor: Dean H Hommer, MD  more...
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Approach Considerations

Laboratory studies usually are not necessary in evaluating and diagnosing an Achilles tendon rupture or injury, although evaluation may help to rule out some of the other possibilities in the differential diagnosis. These laboratory tests, all of which are normal in Achilles tendinosis, include the following:

  • Complete blood count (CBC) with differential

  • Coagulopathy panel

  • Erythrocyte sedimentation rate

  • Arthritis panel

Imaging studies can aid in the diagnosis and evaluation of Achilles tendon pathology, but typically they are not needed. Like laboratory studies, however, they can be helpful in evaluating possibilities in the differential diagnosis and should be ordered as clinically indicated.


Imaging Studies

Plain radiography

Radiography may reveal tendon calcifications in tendinosis or spurs at the calcaneal insertion site, but neither is diagnostic for Achilles tendinosis.

Radiographs are more useful for ruling out other injuries than for ruling in Achilles tendon ruptures. The bones appear normal in patients with a ruptured Achilles tendon, although soft tissue swelling may be evident. [55]

Radiographs of the tibia and fibula often are indicated when the patient’s history shows trauma that may have resulted in fracture of these long bones. Radiographs of the knee and ankle may help to discover findings of degenerative or inflammatory arthropathies.


Ultrasonography of the leg and thigh can help to evaluate the possibility of deep venous thrombosis and also can be used to rule out a Baker cyst. Moreover, in experienced hands, ultrasonography can identify a ruptured Achilles tendon or the signs of tendinosis.

Unlike magnetic resonance imaging (MRI), ultrasonography cannot distinguish a partial tear from tendinosis.

In a small study, De Zordo et al concluded that, in terms of revealing the characteristics of Achilles tendinosis, the ultrasonographic technique known as sonoelastography was comparable to clinical examination and ultrasonography only in the identification of distinct softening of the Achilles tendon. However, very early changes in tissue elasticity in Achilles tendinosis may cause mild softening, which should be assessed in follow-up studies. [56]


MRI can facilitate definitive diagnosis of a disrupted tendon. This is especially useful when considering the possibility of partial disruption of the Achilles tendon. Partial disruption often is undetectable clinically and may be misdiagnosed as simple Achilles tendinosis; however, partial Achilles disruption often responds to surgical intervention. Imaging the knee can confirm a Baker cyst, as well as the probable underlying pathology causing the Baker cyst. [57]

MRI can also distinguish between paratenonitis, tendinosis, and bursitis. [55] In paratenonitis, MRI can reveal fluid in and around the tendon, while in chronic paratenonitis, the paratenon may be seen as thickened and fibrotic.

In tendinosis, increased MRI signal is evident in the tendon and degenerative changes, and partial tears may occasionally be seen. Keep in mind that these MRI findings may also be present in asymptomatic individuals.