Relationship between haematoma in femoral neck fractures contamination and early postoperative prosthetic joint infection

IntroductionProsthetic joint infection (PJI) after femoral neck fracture is associated with a higher mortality, morbidity and economic costs. Although is well known that the presence of a postsurgical haematoma is associated with infection, in our knowledge there are no articles evaluating the contamination of the femoral neck fracture haematoma and the possible relationship with early postoperative PJI. The aim of our study was to evaluate the prevalence of positive cultures from haematoma in patients with femoral neck fracture and the relationship with early PJI.MethodsA prospective observational study was performed. All patients who underwent hip hemiarthroplasty for a femoral neck fracture from April’08 to February’09 were included. Three samples were taken just after the arthrotomy, a tissue sample, a swab of haematoma and blood of haematoma inoculated into blood culture flasks. Patients received the standard prophylaxis.ResultsA total of 109 patients were treated during this period in our center, 16 were excluded for mistakes during taking samples or for receiving extra antibiotic treatment after or before the surgery of the fracture. In 29 patients (31.2%) one or more intraoperative cultures were positive. Four patients developed an early PJI caused by Gram-negative bacilli (GNB) in all cases. The early PJI rate in the group of patients with negative intraopertive cultures was 3.1% while in the group with one or more positive cultures was 6.9% (p = 0.3). In 3 cases the haematoma was contaminated with a GNB. The PJI rate in patients with intraoperative cultures positive for a GNB was 66.6% (2/3) while in the group of patients without a GNB the infection rate was 2.2% (2/89, p = 0.004, Fisher exact-test). Furthermore in these two patients the microorganism that caused the PJI was the same that had been isolated from the haematoma.ConclusionThe haematoma in femoral neck fractures was contaminated in 31.2% of cases before surgery. The contamination of the haematoma with a GNB was associated with a higher risk of early postoperative PJI.