Human osteoblast stimulation by sera from paraplegic patients with heterotopic ossification.

The pathophysiology of heterotopic periarticular ossification is not understood. Though local agents may be responsible, factors present in the serum may be contributory. Sera from 4 paraplegic patients with heterotopic ossification and 4 'normal' paraplegics were incubated with human osteoblasts in tissue culture and their metabolic activity was measured quantitatively. There were significantly greater levels of osteoblast stimulating factors present in the sera of ossifying patients, (p less than 0.01). These factors may contribute to the pathogenesis of heterotopic ossification.