Schuetz and coworkers (2005) have noted that the symptoms of heterotopic ossification appear 3-12 weeks after spinal cord injury.  SCI patients typically present with joint and muscle pain, parasthesias and tissue swelling in the involved region, accompanied by mild fever (Thomas & Amstutz 1987; Orzel & Rudd 1985; Smith 1998;Shehab et al. 2002).  In the initial stages of HO, clinical signs of inflammation are nonspecific (Neal 2003).