Description

Heterotopic Ossification (HO) is not a rare finding and is associated with many conditions particularly when there has been tissue damage. HO may be an incidental, asymptomatic finding or be severe requiring mechanical intervention for symptoms or function improvement. A very dramatic case of HO of uncertain etiology is presented.

A 66-year-old woman presented with dyspnea, reduced ejection fraction heart failure exacerbation, long standing Rheumatoid Arthritis (RA), and hip replacement. There were no overt findings in the areas of calcification. Laboratory findings were unrevealing for calcium, phosphorus, alkaline phosphatase, electrolytes and renal function. The images show the extensive, dense, bilateral shoulder calcifications and soft tissue streaky calcification in the leg and hip.

HO is a complication of trauma, burns, neurologic injury, autoimmune inflammatory diseases and orthopedic procedures especially hip arthroplasty. HO was first described in World War I from blast injuries. It has been an important problem in Iraq and Afghanistan war veterans. HO may present with restriction of movement about the joint, pain and erythema. Most studies report HO after hip arthroplasty in up to 40%. NSAIDs and radiation have been utilized to prevent HO. HO in association with RA with and without joint surgery is frequently reported even in association with the temporomandibular joint. The underlying etiology of HO may be related to more pluripotential cells differentiating into osteoblastic cells in the soft tissue or periarticular inflammatory changes associated with the underlying etiologies. RA seems the likely etiology in the case of this woman.

Figure 1: Clinical image.

Figure 2: Clinical image.