Hip

Heterotopic ossification (HO) is a common complication after hip surgery and has been described in elective and traumatic patients. HO is frequently described after acetabular fracture fixations and total hip arthroplasties but occasionally has been reported after arthroplasty revisions, arthroscopy and proximal femur fracture fixation. The etiology of HO is not entirely known; the prevalence about the hip changes according to type of procedure, approach and specific patient-related factors. HO is often asymptomatic and detected only as an incidental finding on post-operative radiographs. When symptomatic, it most commonly causes decreased hip range of motion, and - in severe cases - complete bony ankylosis. The Brooker Classification for HO of the hip is based on an anteroposterior radiograph and is the most used worldwide, although it presents several limits and has been extensively criticized. When HO of the hip becomes clinically significant, management often includes surgical excision. This chapter discusses the etiology, classification, diagnosis, treatment of and prophylaxis against the finding of HO about the hip.