From Cell Biology to Tissue Engineering


Nerve distributions in insertional Achilles tendinopathy - a comparison of bone, bursae and tendon

Gustav Andersson1,2*, Ludvig J. Backman1*, Jens Christensen1 and Håkan Alfredson3

1Department of Integrative Medical Biology, Section for Anatomy, 2Department of Surgical and Perioperative Science, Section for Hand and Plastic Surgery and 3Department of Surgical and Perioperative Science, Sports Medicine Unit, Umeå University, Umeå, Sweden * Contributed equally as joint first authors

Offprint requests to: Håkan Alfredson, MD, PhD, Professor, Department of Surgical and Perioperative Science, Sports Medicine Unit, Umeå University, SE-90187 Umeå, Sweden. e-mail: hakan.alfredson@idrott.umu.se

Summary. Background/Aim: In a condition of pain in the Achilles tendon insertion there are multiple structures involved, such as the Achilles tendon itself, the retrocalcaneal bursa and a bony protrusion at the calcaneal tuberosity called Haglund’s deformity. The innervation patterns of these structures are scarcely described, and the subcutaneous calcaneal bursa is traditionally not considered to be involved in the pathology. This study aimed at describing the innervation patterns of the four structures described above to provide a better understanding of possible origins of pain at the Achilles tendon insertion. Methods: Biopsies were taken from 10 patients with insertional Achilles tendinopathy, which had pathological changes in the subcutaneous and retrocalcaneal bursae, a Haglund deformity and Achilles tendon tendinopathy as verified by ultrasound. The biopsies were stained using immunohistochemistry in order to delineate the innervation patterns in the structures involved in insertional Achilles tendinopathy. Results: Immuno-histochemical examinations found that the subcutaneous bursa scored the highest using a semi-quantitative evaluation of the degree of innervation when compared to the retrocalcaneal bursa, the Achilles tendon, and the calcaneal bone. Conclusions: These findings suggest that the subcutaneous bursa, which is traditionally not included in surgical treatment, may be a clinically important factor in insertional Achilles tendinopathy. Histol Histopathol 32, 263-270 (2017)

Key words: Insertional Achilles tendinopathy, Innervation, Subcutaneous bursa, Retrocalcaneal bursa

DOI: 10.14670/HH-11-790