Heterotopic ossification: a challenging complication of total hip arthroplastyrisk factors, diagnosis, prophylaxis and treatment

Background: This review is intended to summaries the risk factors, classification, diagnosis and treatment of heterotopic ossification (HO) of previously published studies. Results: Heterotopic Ossification is a common complication of total hip arthroplasty. Its prevalence isn’t the same in all of the patient groups. Frequency of HO varies from 15% to 90%. Hip ankylosis, male gender and previous history of HO are said to be risk factors with a significant level. Diagnosis is based on a single AP radiograph-the Brooker classification that divides HO into four grades is the most commonly used. The confirmation test that can be used is a bone scan. A great amount of bone metabolic turnover markers have been tested, but none of them seems to be relevant in case of prevention or diagnosis of HO. The most effective prophylactic treatment is radiotherapy or administration of nonsteroidal anti-inflammatory drugs. Over the years a lot of different RT protocols has been tested. Nowadays the most often used regimen is 7 Gy given postoperatively in a single dose. The most commonly prescribed drug in prophylaxis of HO is indomethacin. Also, the efficacy of ibuprofen and diclofenac were proven. Recently researchers focused on selective COX-2 inhibitors. They appear to be as effective as nonselective NSAIDs having less side effects. The one and only treatment of HO is a revision arthroplasty.