Incidence and risk factors for pin tract infection in external fixation of fractures
Background: Pin tract infection is a complication when using external fixation. The objective of this study was to estimate the incidence, rate and risk factors for pin tract infections after external fixation in the orthopedics wards in a major teaching hospital in Togo (West Africa).
Methods: A one year prospective cohort study was conducted at the Tokoin Teaching Hospital in Lomé. All trauma patients treated by external fixation during this period were included in the study. There were 50 patients with 52 fractures who underwent external fixation. Their mean age was 33.9 years. The number of pins used was 257. Patients were interviewed and daily observed during their hospitalisation. Surveillance was continued if the patients were discharged before the removal of the external fixator. Care of the pin site was performed in accordance with a standard protocol for all patients. The scoring system for pin-tract infection described by Checketts was applied to each pin site with the same assessor scoring all pins. To estimate the risk factors of the pin tract infection, statistical analyses were performed. The level of statistical significance was set at p<0.05.
Results: Assessment of these pins after operation revealed pin tract infections around 152 pins. The incidence rate of pin tract infections was 59.1%. According to Checketts' scoring system for pin tract infection, there were 93 pins scored grade 1, 32 pins grade 2, 15 grade 3, 8 pins grade 4 and four pins grade 5. No pin scored grade 6. According to fracture sites requiring external fixation, the incidence rate of pin tract infection was 40.6% for distal radius fractures, 57.5% for tibia fractures, and 87.5% for femur fractures. The incidence increased from 20.5% in closed fractures to 75.9% in open fractures. When the pins were inserted manually, the incidence rate was 35.5%. Analysis identified three risk factors for pin tract infections: femur fractures (OR: 13.61; 95% CI: 6.69-27.68; p< 0.001), open fractures (OR: 2.67; 95% CI: 1.34-5.33; p= 0.005), and when pins were inserted with power (OR: 3.47; 95% CI: 1.51-7.95; p= 0.003).
Conclusion: There is a high incidence of pin tract infections after external fixation for fractures in our department in comparison with other series from developed countries and some developing countries. Despite the limitations of this study, several variables have been found as factors which may influence these complications. Points for intervention could be an adequate pin insertion technique and a better pin care.
Key words: External fixation, pin tract infection, fracture, developing country