The long-term results of pilon fractures are rarely documented. The present study evaluated the long-term results related to each fracture pattern of a pilon fracture treated with open reduction and plating. One hundred and twenty-eight pilon fractures with a mean 10-year follow-up were divided into three groups, based on the Ruedi-Allgower classification. Group A was composed of 39 patients with Ruedi-Allgower type I fractures; group B comprised 62 patients with type II fractures; and group C included 27 patients with type III fractures. The radiographs were reviewed for adequacy of fracture reduction and posttraumatic arthrosis. At the end of follow-up, the clinical results were evaluated using a rating scale. Group C had significantly lower excellent and good reduction rates than group A or B (P < 0.05). Groups B and C had progressively increased ankle arthrosis with time (P = 0.043, P = 0.049, respectively). Group C had more unsatisfactory clinical outcomes than group A or B (P < 0.05). Operative concurrent fixation of the fractured fibula resulted in a better outcome than non-operative treatment (P < 0.05). Open fractures had significantly lower satisfactory outcomes than closed fractures (60.5% versus 78.9%, P < 0.05). Open reduction with plating was a reasonably effective procedure for the treatment of Ruedi type I pilon fractures. The long-term outcome of pilon fractures was affected by fracture patterns, fibular length restoration, quality of reduction, and severity of soft tissue injury. Posttraumatic arthrosis affecting the ankle after a severe pilon fracture (Ruedi type II or III) was a progressive disease, and required long-term follow-up.