Total Hip Arthroplasty Procedure Frequencies in Patients with Osteonecrosis versus Osteoarthritis

Abstract

Atraumatic osteonecrosis (ON) of the hip is a debilitating disease. Multiple surgical treatment options are available ranging from joint-preserving procedures to total hip arthroplasty (THA), which is the most commonly performed treatment not only for ON but also for osteoarthritis (OA). Multiple studies have described the rates and trends of THA for OA and ON; however, none have directly compared the two. Therefore, the purpose of this study was to (1) determine the frequency and trends of joint replacement procedures; (2) compare these findings between the ON and OA populations; and (3) assess trends for revision total hip arthroplasty (rTHA). The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database was evaluated for this study. All patients in this database obtained between 2008 and 2014 who had a diagnosis of hip ON or OA were identified using International Classification of Disease, 9th revision codes for hip ON and OA. This yielded 68,434 patients, including 3,816 patients with ON (mean age: 55 years, range: 18–90 years) and 64,618 patients with OA (mean age: 65 years, range: 18–90). The Cochran-Armitage test for trends was used to assess the differences in THA and rTHA rates over the study time period for each cohort. To compare whether these rates were different between ON and OA patients, we performed a Z-test between the groups for each year. The annual number of primary THA performed increased for both ON and OA between 2008 and 2014 (from 62 to 989 and from 1,011 to 19,004, respectively). The rate of primary THA significantly increased from 69 to 88% in ON patients. The rate of THAs for ON, out of all THAs performed for both ON and OA, decreased from 5.8% in 2008 to 4.9% in 2014. . The rate of rTHAs performed for both ON and OA decreased during this time (1.1–0.4% for ON and 0.4–0.2% for OA). ON patients had a significantly higher rate of rTHA only in 2011 and a higher rate of overall revisions. The rate of THA is increasing for both ON and OA, but the slope of the increase is higher for ON. This may indicate that orthopaedic surgeons are more confident in performing THA as newer devices and designs are being developed, allowing for better survivorship and outcomes. Additionally, although the overall rate of revision was higher in the ON cohort, at most annual time points, there was no significant difference. Further research is needed to determine why such trends exist.