Awareness of Heterotopic Ossification in Total Joint Arthroplasty: A Primer.

Heterotopic ossification (HO) is the presence of normal bone in soft tissue where bone should not exist. After direct musculoskeletal trauma of the surrounding soft tissue, HO is hypothesized to develop from a dysfunction of normal lamellar bone formation and remodeling that appears in nonskeletal areas of the body. Acquired HO related to total joint arthroplasty (TJA) of the hip and knee forms outside the joint capsule and can be a challenging condition when it impairs the essential healing process after elective surgery. Although HO is rare after elective TJA and thus clinically immaterial, when clinically relevant HO develops, patients may experience the following: 1) limited ambulation, 2) restricted range of motion, and 3) severe pain and discomfort that may lead to loss of function. Ultimately, patients with clinically relevant HO after elective TJA may require additional treatment, including medication, radiation therapy, manipulation under anesthesia, surgical excision of the HO, and possibly revision TJA. Awareness of HO and an understanding of the associated risk factors along with the various management options will enable health care practitioners and their patients to optimize their surgical outcomes.