The value of serum creatine kinase in early diagnosis of heterotopic ossification

Background: Heterotopic ossification (HO) is a complication of spinal cord injury (SCI) characterized by formation of ectopic bone. Early diagnosis is critical, but available diagnostic methods have drawbacks. Serum creatine kinase may be a marker for the development and severity of HO. Participants: 18 SCI patients with diagnosed HO based on clinical findings and bone scintigraphy. Methods: Serum creatine kinase levels were taken at the time of diagnosis of HO and during subsequent etidronate therapy. Results: Of the 14 patients with normal creatine kinase values, 13 had no evidence of HO on follow-up radiographic examination. Of the 4 patients with elevated creatine kinase, all developed radiographic signs of HO. Conclusion: Elevated serum creatine kinase may be associated with a more aggressive course of HO as well as resistance to etidronate therapy. Further studies are needed to determine whether creatine kinase may serve as a marker for early, active HO.