Heterotopic ossifications in patients after severe blunt trauma with and without head trauma: incidence and patterns of distribution.

OBJECTIVE:
To investigate the incidence and distribution of heterotopic ossifications in patients with blunt multiple trauma with and without associated head trauma.

DESIGN:
Retrospective.

SETTING:
Level I trauma center.

PATIENTS:
Patients were included if they were treated between August 1987 and September 1995. Inclusion criteria included age between 16 and 65 years, injury severity score (ISS) of more than twenty points, and clinical reexamination performed more than three years after the initial injury.

METHODS:
The records of each patient were abstracted to determine the ISS, the Glasgow coma score (GCS), and parameters describing the course of intensive care. For each patient, a reexamination was performed between January and September 1998. Patients with multiple trauma and associated head trauma (Group PTH, polytrauma, GCS less than nine points, and head computed tomography scan abnormalities) and patients with multiple trauma without associated head trauma (Group PT, polytrauma, GCS of at least nine points, and normal head computed tomography scans) were compared. A clinical reexamination was performed to evaluate functional outcome.

RESULTS:
Sixty-four patients belonged to Group PTH and 124 patients belonged to Group PT. There were no differences in the age (Group PTH, 28.9 +/- 1.6 years; Group PT, 29.2 +/- 2.1 years) or severity of injury (ISS Group PTH, 31.0 +/- 5.3 points; ISS Group PT, 33.0 +/- 6.1 points) among patients in the two groups. The overall incidence of periarticular heterotopic ossification was comparable in patients with multiple trauma with and without head injury (Group PTH, 30 of 64 patients [46.9 percent]; Group PT, 53 of 124 patients [42.7 percent]). The duration of ventilation was significantly higher in Group PT (Group PTH, 9.3 +/- 2.4 days; Group PT, 14.2 +/- 3.1 days; p = 0.02). In the subgroups in which heterotopic ossification developed (PT-HO and PTH-HO), patients in PT-HO had a significantly higher incidence of heterotopic ossification, as compared with patients in PTH-HO at initially uninjured joints (Group PTH-HO, 1 of 30 patients [3.3 percent]; Group PT-HO, 10 of 53 patients [18.9 percent]; p = 0.04).

CONCLUSIONS:
There was a high incidence of heterotopic ossification around those joints that were initially classified as uninjured in patients without head trauma. This finding suggests that pathogenic pathways independent of head trauma, such as long-term ventilation, play a main role. Causative factors for the development of heterotopic ossification at initially uninjured joints in long-term ventilated patients with multiple trauma with and without head trauma remain to be elucidated.