Diagnosis

Diagnosis of chronic rupture is challenging since by the time patients present to the clinician:

• the pain and swelling have often subsided
• the gap between the tendon ends has filled in with fibrous tissue
• active plantar flexion, although weak, may be possible through the action of the tibialis posterior, flexor hallucis longus, flexor digitorum longus, and peroneal muscles

Hence a high index of suspicion is needed along with other investigations to diagnose the condition (1).

Clinical examination:

• on inspection there may be
  • a visible gap at the rupture site
  • wasted calf muscles
  • clawing of the toe and higher medial arch of the foot (results due to the accommodation of the long toe flexors for the lack of function of the gastrocnemiussoleus complex)
• Thompson test (or calf squeeze test), Matles test can be used to detect a ruptured Achilles tendon

Imaging

• lateral radiographs of the ankle
  • distorted Kager’s triangle (a small fat-filled space between the anterior aspect of the Achilles tendon, the posterior part of the tibia, and the superior aspect of the calcaneus)
  • can rule out other diagnoses such as calcaneal avulsions or other osseous injuries
• ultrasonography
  • shows tendon discontinuity with decreased or increased echogenicity, depending on the chronicity of the rupture3
• MRI (1,2)

Reference:

• (1) Maffulli N, Ajis A. Management of chronic ruptures of the Achilles tendon. J Bone Joint Surg Am. 2008;90(6):1348-60.
• (2) Maffulli N, Via AG, Oliva F. Chronic Achilles Tendon Disorders: Tendinopathy and Chronic Rupture. Clin Sports Med. 2015;34(4):607-24.