Diaphyseal femoral fracture (DFF) and fixation elicit a bistep inflammatory response (two-hit model). The timing of fixation potentially affects lung function and blood biochemistry. In 24 patients with DFF we measured CRP, albumin, albumin/globulin ratio (A/G) total protein, triglycerides, low (LDC) and high (HDC) density cholesterol at (1) admission, (2) day of operation, and (3) 48 hours postoperatively. We considered group A: (early fixation, day 1–4, 2.6±0.9, n=12) and B: (late fixation, day 5–12, 8.7±2.6, n=12). Statistical analysis was performed by ANOVA and multivariable tests. CRP increases from injury to operation and further to 48 hours postoperatively (p< 0.001) in both groups. Early fixation results in vigorous CRP increase, compared to late fixation, yet the pattern is parallel. Biphasic decrease of albumin (p< 0.001), A/G (p< 0.001) and total protein (p< 0.001), attributable to the inflammatory response, and that of HDC (p< 0.001) and LDC (p< 0.05) are identical in both groups.

It is known that CRP peaks at 48 hours posttrauma. In early operation there is an additive effect of the two inflammatory hits, whereas, in delayed fixation the first hit fades, thus lowering the starting point of the second hit. Protein and HDC biphasic drop is not affected by the timing of fixation. We have no explanation for HDC drop. The timing of femoral shaft fracture fixation affects significantly CRP release and its impact on convalescence is worth investigating.