THE FEMORAL INTRAMEDULLARY CYTOKINE MICRO-ENVIRONMENT FOLLOWING FEMORAL SHAFT FRACTURE AND INTRAMEDULLARY REAMING

Abstract

Patients with a femoral shaft fracture requiring intra-medullary nailing were recruited to investigate if the femoral canal could be a potential source of inflammatory cytokines, previously implicated in the pathogenesis of life-threatening inflammatory complications.

Femoral and peripheral blood samples were obtained at the time of surgery from patients with a femoral shaft fracture requiring intramedullary nailing. The local femoral intramedullary and peripheral release of a group of ten Th1 and Th2 cytokines concentrations (IL-1b, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, GM-CSF, TNF-a and IFN-g) after femoral shaft fracture and intramedullary reaming, if performed, was measured using a Human Cytokine Antibody 10-plex Bead Kit. A control group of patients(n=3) undergoing hip replacement was established to allow comparison with the normal femoral intramedullary cytokine environment.

21 patients with a femoral shaft fracture were recruited. Femoral shaft fracture caused a significant increase in the local femoral concentrations of IL-6 (median 3967pg/ml; range 128–25,689pg/ml) and IL-8 (median 238pg/ml; range 8–8,288pg/ml) compared to the femoral control group(p=0.0005 and p=0.001 respectively). No significant local femoral release of the other cytokines was demonstrated. In the patients who underwent intramedullary reaming of the femoral canal (n=6), a further significant local release of IL-6 (median post-ream 15,903pg/ml; range 1,854–44,922pg/ml) and IL-8 (median post-ream 1,443pg/ml; range 493–3,734pg/ml) was demonstrated (p=0.01 and p=0.03 respectively), thus showing that intramedullary reaming can cause a significant local inflammatory response.

Femoral shaft fracture produces a local inflammatory response releasing large amounts of the cytokines IL-6 and IL-8 into the local femoral environment but not of the other Th1 and Th2 cytokines studied. Reaming, produced significant elevation in local femoral IL-6 and IL-8 concentration, suggesting a local femoral response as a result of this procedure. Possibly, local femoral environment may act as a cell-priming or stimulating zone, for circulating inflammatory cells.