Heterotopic para-articular ossification of the proximal interphalangeal joint.

A 24-year-old woman sustained a closed head injury. She regained consciousness over a 2-month period but heterotopic ossification developed around both elbows and the proximal interphalangeal joints of her left ring and long fingers. The new bone was allowed to mature and was subsequently resected from both elbows and the fingers with substantial improvement in function. There is no clear explanation for the formation of such heterotopic bone.