A 57 year old retired male truck driver and known sufferer from myaesthenia gravis presented to the accident and emergency department with severe pain in his left ankle. The pain had begun suddenly while standing on tiptoe. His myaesthenia gravis had been treated with oral prednisolone and azathioprine for three years. Physical examination revealed a palpable gap over the posterior ankle. As Symmonds test was negative, a clinical diagnosis of partial rupture of the Achilles …