Tendinopathy literally means a disease or disorder of a tendon and is typically used to describe any problem involving a tendon. While many define tendinopathy as an umbrella term to describe all tendon pathology, others may use it to describe a chronic tendon condition that fails to resolve.
The prevalence of tendinopathy in the general population is 2-5%. Active and sporting individuals are at increased risk of tendinopathy although it is also commonly seen in non-active individuals. The prevalence in some populations can be high, e.g. patellar tendinopathy in up to 40% of volleyball players, however, sites and prevalence will depend on the sport and level played 2.
Tendinopathy is a clinical syndrome consisting of pain, tendon swelling and impaired function 3.
The pathophysiology of tendinopathy is yet to full elucidated but one popular theory is the continuum model with inflammation rather than degeneration implicated 2,3:
- reactive tendinopathy
- tendon dysrepair (also known as "failed healing")
- degenerative tendinopathy
Risk factors can be intrinsic or extrinsic 2:
- sex: increased in female
- age: increases with age
- medications, e.g. fluoroquinolones, local and systemic glucocorticoids
- metabolic, e.g. obesity, type 2 diabetes mellitus, dyslipidemia, hypercholesterolemia
- poor muscle strength
- excessive tendon beyond tendon capacity, in particular, activities with a high-energy storage component (e.g. jumping in basketball, kicking sports)
- amount of loading (e.g. increased training time)
- change in loading
- "abusive loading" (i.e. unaccustomed activity) in non-active individuals
Ultrasound is the mainstay of imaging tendinopathy, with MRI as the second-line investigation. Plain radiograph and CT have a limited role, sometimes used to assess for calcification or associated avulsion fractures.
Plain radiographs have a low sensitivity for tendinopathy but localized soft tissue swelling and calcifications may be seen. Calcified insertional tendinopathy is usually well seen and a common incidental finding.
Specific features will depend on the site of tendinopathy but general features include 4:
- early changes include tendon thickening, contour change, echotexture change
- progressive changes include further tendon thickening, loss of normal fibrillar pattern with hypoechogenicity
- may be focal or diffuse
- color Doppler may demonstrate neovascularity
The above changes can be seen in asymptomatic individuals but prominent, tendon thickening, loss of fibrillar pattern and neovascularity are more commonly seen in symptomatic patients 4.
There is overlap in the imaging features on ultrasound with tendon thickening and contour change present 5.
- T1: hyperintense
- T2: hyperintense
- GRE: hyperintense (often before T1 spin echo hyperintensity) 5
- T1C+: enhancement 5
Unfortunately, these features are indistinguishable from myxoid degeneration.
- adjacent capsular or ligamentous injuries
- tendon instability
- on ultrasound, anisotropy artifact can mimic hypoechoic tendinopathic changes 4
- on MRI, magic angle artifact can mimic hyperintense tendinopathic changes 5
- 1. Fredberg U. Tendinopathy--tendinitis or tendinosis? The question is still open. (2004) Scandinavian journal of medicine & science in sports. 14 (4): 270-2. doi:10.1111/j.1600-0838.2004.404_3.x - Pubmed
- 2. Michael Girdwood, Sean Docking, Ebonie Rio, Jill Cook. Pathophysiology of Tendinopathy. (2019) Digestive diseases and sciences. 63 (12): 23. doi:10.1007/978-3-662-54184-5_3 - Pubmed
- 3. D'Addona A, Maffulli N, Formisano S, Rosa D. Inflammation in tendinopathy. (2017) The surgeon : journal of the Royal Colleges of Surgeons of Edinburgh and Ireland. 15 (5): 297-302. doi:10.1016/j.surge.2017.04.004 - Pubmed
- 4. Robinson P. Sonography of common tendon injuries. (2009) AJR. American journal of roentgenology. 193 (3): 607-18. doi:10.2214/AJR.09.2808 - Pubmed
- 5. Hodgson RJ, O'Connor PJ, Grainger AJ. Tendon and ligament imaging. (2012) The British journal of radiology. 85 (1016): 1157-72. doi:10.1259/bjr/34786470 - Pubmed