Heterotopic ossification (HO) is the process by which mature lamellar bone forms in the soft tissues surrounding bone. HO typically occurs after trauma, neurologic injury, hip surgery, or knee surgery. HO is the most common complication that occurs after hip arthroscopy, with postoperative HO rates higher than 40% reported in patients without proper prophylaxis. The pathophysiologic mechanisms underlying HO have not been completely elucidated; however, HO likely results from multifactorial elements contributing to abnormal bone growth. Recently, various cytokines and inflammatory mediators, including bone morphogenetic protein-2, substance P, and calcitonin gene-related protein, have been implicated in the pathogenesis of HO. These factors may lead to an immune response cascade that creates a hypoxic microenvironment, resulting in bone growth. This bone growth often is painful and debilitating for patients, resulting in decreased range of motion and poor functional outcomes. Therefore, surgical excision of HO is indicated in some patients, taking into consideration patient presentation, symptomatology, and complete maturation of the HO site. Careful technique is essential to avoid poor outcomes and ensure consistent results.

This video demonstrates arthroscopic excision of hip HO. The video provides an overview of the pathogenesis, diagnosis, and management of HO followed by a discussion of the indications for arthroscopic HO excision. The video discusses the case presentation of a 65-year-old man with continued right hip pain 2 years after undergoing right hip arthroscopy for labral repair. Physical examination revealed a marked antalgic gait and lateral trochanteric tenderness of the right hip. The patient also had pain with hip flexion. Radiographs demonstrated a focus of HO in the soft tissues along the lateral aspect of the right hip extending from the superolateral aspect of the right acetabulum, measuring approximately 2.5 cm in length. Arthroscopic excision of this focus of HO was indicated. Excellent restoration of right hip function was achieved postoperatively. The patient was advanced through a standardized rehabilitation protocol with gradual relief of his symptoms. Arthroscopy is an effective procedure for management of HO of the hip. Surgical intervention requires adequate exposure and familiarity with the anatomy and lesions observed on preoperative imaging studies. Although studies have demonstrated good outcomes in patients who undergo arthroscopic excision of hip HO, results are contingent on careful and consistent technique.