There is evidence that fractures heal more rapidly in patients with head injury. We measured the circulating level of interleukin-6 (IL-6) and its soluble receptor (sIL-6R) and soluble glycoprotein 130 (sgp130) in serum from patients who had sustained a head injury with and without fracture and compared these with levels found in control subjects.

Within 12 hours of injury the serum level of IL-6 was significantly higher in patients with head injury and fracture compared with the control group. Levels of IL-6 were also significantly higher in patients with head injury and fracture compared with fracture only. While there was no significant difference in circulating levels of sIL-6R in the initial samples they were increased one week after surgery in patients with head injury and fracture and with head injury only. In addition, reduced levels of sgp130 in patients with head injury with and without fracture indicated a possible reduction of the inhibitory effect of this protein on the activity of IL-6.

Our study suggests that IL-6 may be involved in altered healing of a fracture after head injury.

There is evidence to suggest that fractures heal more rapidly in patients with a head injury as a result of systemic factors released from the site of this injury. We have measured the circulating level of insulin-like growth factor-1 (IGF-1) and IGF binding protein-3 (IGFBP-3) in serum because of their known involvement in the stimulation of the activity of osteoblasts and the healing of fractures.

The serum level of IGF-1 was significantly lower in patients with both head injury and fracture and fracture only compared with that in healthy volunteers (p < 0.01 and p < 0.02, respectively). The level of IGFBP-3 was also significantly lower in patients with both head injury and fracture (p < 0.01).

Our findings showed, however, that the level of IGF-1 and IGFBP-3 varied from week to week in both the patients and healthy control subjects. These results indicate that the levels of circulating IGF-1 and IGFBP-3 are unlikely to be responsible for the altered healing of fractures seen in conjunction with head injury.