Session V - Post Traumatic Reconstruction

Delayed Union and Nonunion of the Tibia Associated with Multifocal Osteomyelitis from External Fixator Pins

Carlos F. Sancineto, MD; Maria V Gimenez, MD; Ivan F. Rubel, MD, Hospital Italiano, Buenos Aires, Argentina

Introduction: External fixation provides good control of tibial fractures with soft tissue compromise in the emergency. Once the emergency is under control, intramedullary nailing is a better option for the majority of midshaft fractures. One-stage exchange nailing can be performed safely before the pin sites become colonized. Unfortunately, after several weeks of external fixation, the fracture sometimes does not heal, and infected pin tracts develop osteomyelitis. We report on the treatment of a series of patients with delayed union or nonunion of the tibia complicated by multifocal osteomyelitis associated with external fixator pins.

Methods: The clinical charts of 24 patients with delayed union or nonunion of the tibia initially treated with external fixators were retrospectively reviewed. The series consisted of 15 men and 9 women with an average age of 40 years (range, 20 to 74) and at least I year of follow-up (range, 1 to 7). Initial injury was an open tibia fracture in 22 cases and a closed fracture in 2. Sixteen patients were initially treated at another institution and referred to our hospital for further treatment. Fifteen of the cases underwent major reconstructive procedures, and 7 cases required only minor local debridement and skin grafting. External fixators were kept in place until the soft tissues at the fracture site healed. External fixation time averaged 116 days (range, 28 to 288). Although appropriate pin care was encouraged, multiple gross pin tract infections developed in all the cases. Delayed unions and nonunions were treated by exchange reamed intramedullary nailing. The exchange protocol consisted of removal of the external fixator, debridement, and culture of bone from the pin sites, cast immobilization, specific intravenous antibiotics for 6 weeks on an out patient basis and a negative biopsy report after antibiotic treatment was completed. Outcome measurements included recurrence of infection and healing of the delayed union or nonunion.

Results: Multiple bacteria were isolated from the pin sites, confirming the clinical diagnoses of osteomyelitis. The incidence of gram negative bacteria increased on the more distal pins, closer to the foot. Twenty-three of the fractures healed on the first nailing attempt at an average time of 4 months (range, 2 to 7). One case required re- nailing at 4 months, finally healing at 6 months from the initial procedure. No recurrence of deep infection was identified. Two patients developed superficial infections and were kept on suppressive antibiotics until the bone healed completely and the nail was removed.

Discussion and Conclusion: Delayed union and nonunion of the tibia associated with multiple gross pin tract infections presents a difficult challenge to the orthopaeclic surgeon. Although fixators have to be kept in place until soft tissues heal, the fracture does not always heal in the same time period, and delayed union or nonunion develops. Grossly infected pin sites and traumatized soft tissues at the nonunion site make ORIF risky. Use of exchange nailing after prolonged external fixation of the tibia is also controversial. Although some authors suggest that it can be safely performed before 2 weeks, little information is available regarding exchange nailing for delayed union or nonunion of the tibia associated with multifocal osteomyelitis. Local demographic inconveniences and late referral to specialized orthopaedic centers were crucial factors for the development of this combination. Through the use of the staged protocol mentioned here, we were able to perform delayed exchange nailing of the tibia with a considerable rate of success.