Heterotopic ossification (HO) is characterized by the pathologic formation of mature lamellar bone in muscle and soft tissue. It presents clinically with localized pain, reduced motion, and swelling. The process of HO occurs due to abnormal tissue repair, and most commonly occurs in young adults. Significant predisposing factors include total hip arthroplasty (THA), fractures, spinal cord and traumatic brain injuries, and thermal injuries. The overall incidence of HO is up 42% to 57% after THA, and the incidence of extensive HO post THA is 2% to 7%. Certain patient and surgical-related factors have been associated with an increased risk of HO. Patient aspects include a history of Paget's disease, ankylosing spondylitis, and hypertrophic osteoarthritis; surgical factors include the use of cemented implants and prolonged time of ischemia. Post-operative celecoxib use has been associated with a significant lower incidence of HO compared to controls. Furthermore, among COX-2 selective inhibitors, celecoxib has been associated with the lowest incidence of HO.~This study looks at patients who have been referred to our orthopaedic clinic and undergone cementless total hip joint replacement surgery through a retrospective review of our pre-existing departmental database. All the data from all patients who meet the inclusion criteria will be collected from our database. Specifically, the age, gender, BMI, pre-operative diagnosis, post operative radiotherapy, preoperative patient-reported outcome measures (PROMs), post-operative PROMs, operative characteristics, and complications. Data from the available PROMs database will need to be converted into a manageable format that is suitable for data analysis. This study looks at the Harris Hip Score, the UCLA Activity Score, and SF-12 PROMs that are collected from each patient as standard of care. Descriptive statistics and para/nonparametric statistics will be used to analyze the data through IBM SPSS software platform for statistical analysis. The independent student t-test and multivariable logistic regression analysis will be used to examine outcome measures.
The primary goal of this observational study is to demonstrate the incidence of heterotopic ossification (HO) in patients with cementless total hip joint replacement surgery over time and secondly, demonstrate the relationship between celecoxib and HO formation. Lastly, investigators will examine the relationship between HO and patient-reported outcome measures (PROMs).