Rupture of the quadriceps tendon.

Complete bilateral, simultaneous and spontaneous rupture of the quadriceps tendon is exceedingly rare; 17 cases have been reported, four with no predisposing cause. This report documents a fifth case, being the first in Dutch literature. Although diabetes, primary or secondary hyperparathyroidism, lupus erythematosus and gout are well-known predisposing factors, this case illustrates that the condition can occur in a previously healthy older patient.