We have recently treated two patients with closed pronation-external rotation bimalleolar ankle fractures. During the surgical explorations, an avulsion type rupture of the posterior tibial tendon was observed. Open reduction and internal fixation of the fracture in conjunction with primary tendon repair has produced excellent clinical results. We wish to report these two cases of this uncommon injury. More important, we wish to point out the association of the tendon rupture in conjunction with a particular type of fracture pattern.