Non-unions after fracture dislocation of the ankle joint are extremely rare with predominantly operative treatment. In contrast, after fractures of the tibial plafond (pilon fractures) infections are seen in the literature in 37 % and non-unions are seen in 27 % after open reduction and internal fixation, requiring secondary ankle arthrodesis in about one quarter of all cases. In contrast to aseptic non-union or arthrosis, which can be salvaged with screw arthrodesis, with prevailing infection and severe osteoporosis external fixation (either one- or two-sided) is the treatment of choice. In isolated non-unions of the malleoli, either plate osteosynthesis with 3.5 low-contact dynamic compression plate or tension banding with autologous bone graft interposition, or alternatively sliding graft technique, is performed with good results.