Heterotopic OssificationPostoperative periarticular bone formation is a common incidental finding on follow-up radiographs. Occasionally it is associated with pain and snapping, requiring surgical excision.20 The reported incidence is variable, from 3.8%21 to 32%.22 Variability may be due in part to some researchers reporting only large amounts and disregarding or overlooking smaller areas in their analysis. The incidence increases with total knee arthroplasty.23
Heterotopic ossification is usually located anterior to the femur, best seen on the lateral film. Ossification may be in the quadriceps musculature or attached to the periosteum on the femur. It may be linear or globular in shape.
Heterotopic ossification anterior to femur in vastus masculature