[Atypical Achilles tendon rupture in Haglund exostosis--a case report].

We report about an unusual case of a rupture of the Achilles tendon in a patient with Haglund's exostosis and long term achillodynia. Intraoperatively, we found a fresh superficial typically located tendon-rupture and an old deep round shaped rupture which was located directly over the cranial edge of the calcaneous bone spur. We presume that the sharp edge of Haglund's deformity was the cause of the deep tendon rupture, because the location of the round shaped rupture was near the exostosis. The additional superficial rupture, caused by an inadequate trauma, induced operative revision consisting of double layer transosseous suturing. In conclusion early operative resection of Haglund's deformity in cases of repeated irritations of the Achilles tendon should be performed to avoid mechanical damage, including the risk of rupture by the hypomochlion-like effect of the exostosis.