Fine structural alterations in chronic Achilles paratenonitis in athletes

Pathol Res Pract. 1985 Oct;180(4):416-23. doi: 10.1016/S0344-0338(85)80115-1.


The fine structural alterations in chronic Achilles paratenonitis were studied in tissue samples obtained from 14 athletes, who were operated on for this complaint and from 3 patients without any history of this disease. In the chronically inflamed paratendineal tissue mainly two types of cells were identified: classic fibroblasts with a smooth and rough endoplasmic reticulum and only a few mitochondria and lysosomes and myofibroblast-like cells with cytoplasmic microfilaments 5-6 nm in diameter, a rough endoplasmic reticulum, some mitochondrias and free ribosomes. These cells represented 19% of 471 studied non-inflammatory cells. In the extracellular space there was an increased amount of fibrils regarded as either type I or type III collagen as sign of tissue repair. Especially around the myofibroblastic cells a fine granular ground substance was found. The amount of ground substance was as a rule increased in pericellular space. Due to the capacity of contraction in healing tissue the myofibroblasts apparently have a role in the clinical symptoms of chronic Achilles paratenonitis.

MeSH terms

  • Achilles Tendon / cytology
  • Achilles Tendon / pathology
  • Achilles Tendon / ultrastructure*
  • Adult
  • Athletic Injuries / pathology*
  • Chronic Disease
  • Humans
  • Inflammation
  • Microscopy, Electron
  • Running