Aims: The purpose of this presentation is to report our protocol for staged exchange nailing of delayed-unions and non-unions of the tibia complicated by multifocal osteomyelitis from infected pin tracts. Methods: Twenty-four patients with delayed or non-union of the tibia initially treated by external þxation were retrospectively reviewed. Fifteen males and 9 females with an average age of 40 years (range 20–74) and at least 1 year of follow up (range 1–7). External þxation was maintained until the soft tissues healed. External þxation time averaged 116 days (range 28–288). Multiple gross pin tract infection developed in all the casesl. Non-unions and delayed-unions were treated by exchange reamed intramedullary nailing. The exchange protocol consisted in the removal of the external þxator, debridement and culture of bone from the pin sites, cast immobilization, speciþc IV antibiotics for 6 weeks, and a negative post-antibiotics biopsy. Outcome measurements included recurrence of infection and healing of the delayed union or non-union. Results: Twenty-three of the fractures healed at the þrst nailing attempt on an average time of 4 months (range 2–7). One case required re-nailing at 4 months and þnally healed at 6 months from the initial procedure. No recurrence of deep infection was identiþed. Two patients developed superþcial infections, suppressive antibiotics were used until complete bone healing and subsequent nail removal. Discussion: By using our staged protocol we were able to perform exchange nailing for non-unions and delayed unions of the tibia complicated by multiple foci osteomyelitis from infected pin tracts with a considerable rate of success.