Achilles tendinopathy

Last revised by Rohit Sharma on 1 Feb 2024

Achilles tendinopathy refers to a combination of pathological changes affecting the Achilles tendon usually due to overuse and excessive chronic stress upon the tendon. It can be seen both in athletes and non-athletes. It is hard to differentiate clinically from paratendinopathy (which is most common). It may or may not be associated with an Achilles tendon tear

It can affect a range of people from athletes to recreational exercisers and even inactive people. It affects non-athletes in around one-third of cases. 

Macroscopically, tendinopathy results in enlargement, disruption of fibrillar pattern and an increase in tendon vascularity. Histopathologically, there is evidence of disorganized proliferation of tenocytes, disrupted organization of collagen fibers, an increase in the non-collagenous matrix, and neovascularization. Usually, there is no evidence of inflammation, but the cause is thought of as a failed healing response 1. Repetitive microtrauma from unusual or excessive mechanical loading is deemed to be a causative factor.

Achilles tendinopathy can be classified as 6

  • midportion: >2 cm from its insertion

  • insertional: <2 cm from its insertion

Ultrasound is the first-line imaging modality 6

Often shows thickening and rounding of the affected portion of the tendon. A cutoff value of 1 cm in anteroposterior diameter is usually used for diagnosis ref. There is also evidence of neovascularization, which, if present, is usually indicative of a poorer outcome and more severe clinical symptoms ref. Additional signs include increased Kager fat pad echogenicity (especially with chronic tendinopathy) and thickening of a hypoechoic paratenon.

Can show increased intratendinous signal and tendon enlargement, with edema in Kager fat pad in cases of tendinosis.

The following should be included as a minimum 6:

  • AP diameter of the Achilles tendon

  • altered structure (e.g. echotexture on ultrasound, signal on MRI)

  • peritendinous or intratendinous vascularization

  • insertional calcifications

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