Aims: 1 To assess the histological changes in patients with Achilles tendinopathy. 2 To map the distribution of nerves and nerve endings within the Achilles tendon

Methods: Tendon biopsy specimens were taken from patients with spontaneous (ie previously painless) Achilles rupture patients and chronic painful tendinopathy patients. ‘Normal’ cadaveric /lacerated tendon biopsies were used for comparison. Sections were stained with H& E for basic histology. Immunolocalisation of nerve tissue was performed with 2 anti-neurofilament antibodies. Non-specific immunoglobulin was used as a negative control.

Results: The number of nerves and nerve endings found within the normal tendons and both groups of degenerate tendons was very low

Only 30% of the normal tendon sections showed any positive staining at all

Compared to 36% of ruptured tendon and 43% of the painful tendinopathy sections.

Conclusions: Tendon rupture and chronic painful tendinopathy biopsies ALL show widespread degenerative changes

There is a paucity of nerve tissue within these tendons, which may have implications for the neurogenic hypothesis of tendon degeneration

There appear be more nerve fibres in vascular areas of the painful tendinopathy biopsies

There may be more nerve fibres in the peritendinous tissue