Nerve distributions in insertional Achilles tendinopathy - a comparison of bone, bursae and tendon.
OBJECTIVE
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
Immunohistochemical 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.
Department of Integrative Medical Biology, Section for Anatomy, Umeå University, Umeå, Sweden.|Department of Surgical and Perioperative Science, Section for Hand and Plastic Surgery, Umeå University, Umeå, Sweden.
Gustav
G
Andersson
Department of Integrative Medical Biology, Section for Anatomy, Umeå University, Umeå, Sweden.
Ludvig J
LJ
Backman
Department of Integrative Medical Biology, Section for Anatomy, Umeå University, Umeå, Sweden.
Jens
J
Christensen
Department of Surgical and Perioperative Science, Sports Medicine Unit, Umeå University, Umeå, Sweden. hakan.alfredson@idrott.umu.se.
Håkan
H
Alfredson
D000125:Achilles Tendon / Q000294:innervation*; D000328:Adult; D002061:Bursa, Synovial / Q000294:innervation; D002111:Calcaneus / Q000294:innervation*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D052256:Tendinopathy