This may result from constitutional dyscrasia, or may be associated with a defective blood supply, as when the nutrient artery is injured.
"Manual of Surgery Volume Second: Extremities--Head--Neck. Sixth Edition."
Alexander Miles Alexis Thomson
He attributes the simultaneous occurrence of these conditions to some blood dyscrasia, uric acid, or the like, affecting the two most used sets of muscles and organs, the legs and the vocal cords.
"Psychotherapy"
James J. Walsh