[Observations of ultrastructural changes on prepared homologous tendon transplants in humans (author's transl)]

Amianthoid fibres in ruptured human tendons

So-called amianthoid fibres were identified in 17 of 460 tendons (3.7%) after spontaneous rupture. These tendons belonged to 10 men and 7 women with an age-range from 18 to 67 years. In 445 postmortem control tendons taken of accidentally killed previously healthy persons amianthoid fibres were not found. Ultrastructurally the tendineal amianthoid fibres differ from normal tendon collagen fibrils in many respects. Their diameter (600-1400 nm) is many times larger than that of native collagen fibrils (20-120 nm). The fibre profile is often irregular and the cross-sectioned fibres have a homogeneous granular appearance. In longitudinal sections, the amianthoid fibres are frequently disintegrated and outspread, and some of the fibres have lost their periodicity. In addition, some of the fibres are angulated and show nonparallel organization. Occasionally the amianthoid fibres are calcified.

Regeneration of human tendons after homologous tendon-graft transplantation. A morphological study of 25 cases

The authors examined the regeneration and incorporation of homologous tendon grafts in 25 patients from 10 days to 20 years after tendon grafting. Newly formed collagen fibers in the place of graft are first observed 3 months after transplantation. The reorganization of tendon grafts begins at the end of the first postoperative year and is accomplished within the second year.

Fine structural alterations in chronic Achilles paratenonitis in athletes

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.