The purpose of this study was to review the outcomes and complications of all circular external fixators (frames) used for the management of sterile and infected fracture non-unions in the lower limb in our institution over a twenty year period. We retrospectively reviewed a prospectively compiled database of all frames applied in our institution and identified all frames which were applied for acute lower limb trauma. We identified 76 non-unions in 76 patients. There were 22 femoral non-unions and 54 tibial non-unions. Five femoral non-unions and 12 tibial non-unions were confirmed infected. The mean time in frame was 281 days for a sterile non-union and 457 days for an infected non-union. There was a union rate of 87% for sterile non-unions and 71% of infected non-unions at cessation of treatment. Factors associated with persistent non-union included cigarette smoking, soft tissue complications, and excessive pin-site toilet by the patient. Lower-limb fracture non-unions can be extremely difficult to treat. The patients included in our study had previously undergone more traditional treatments in an attempt to establish union. The results presented demonstrate that circular frames are an excellent treatment modality in non-unions resistant to other forms of treatment. We would recommend this as a first line treatment for patients at higher risk of developing fracture non-union