Abstract
Aim: To investigate the incidence, risk factors and pathogenic micro-organisms causing superficial and deep infection in subtrochanteric femoral fractures managed with an intramedullary nail. Materials and Methods: Following institutional board approval, all consecutive patients presenting with a subtrochanteric fracture were retrospectively identified, over an 8-year period. Basic demographics, fracture characteristics, fracture union, revision operation, mortality and other complications were reported and analysed. Variables deemed statistically significant (p-value < 0.05) were then included into a revised adjusted model of logistic regression analysis, where we reported on the odds ratio (OR). Results: The overall incidence of infection was 6.4% (n = 36/561; superficial: 3.7%; deep: 2.7%). Associations with deep infection included: non-union (OR 9.29 (2.56-3.38)), the presence of an open fracture (OR 4.23 (3.18-5.61)), the need for massive transfusion (OR 1.42 (2.39-8.39)), post-operative transfusion (OR 1.40 (1.10-1.79)) and prolonged length of stay (OR 1.04 (1.02-1.06)). The Commonest causes of superficial infection were Staphylococcus aureus (28.5%), enteric flora (23.8%) and mixed flora (23.8%); whereas coliforms (60%) and Staphylococcus aureus (26.7%) were the commonest micro-organisms isolated in deep infection. Polymicrobial infection was identified in 38.5% and 80% of superficial and deep infections, respectively. Conclusion: Causative micro-organisms identified in both superficial and deep infection were similar to those reported in post-traumatic osteomyelitis. In an attempt to minimise infection, the treating clinician should focus on modifiable risk factors with adequate patient optimisation, prompt surgical treatment, adequate antibiotic coverage and wound care when treating patients with subtrochanteric femur fracture.