The prevalence of femoroacetabular impingement as an aetiologic factor for end-stage degenerative osteoarthritis of the hip joint: analysis of 1,000 cases

Objective: The main purpose of the present study was to determine the prevalence of FAI among patients who underwent total hip arthroplasty (THA) with the diagnosis of end-stage osteoarthritis (OA) of the hip joint in a tertiary referral centre. Design: A retrospective search of the institutional archive database for patients who had undergone THA between the years 2005 and 2010 was conducted with the analysis of the recorded radiographic images. A total of 1,004 patients including 690 (68.7%) females and 314 (31.3%) males were identified. All radiographs were reviewed by 3 of the authors. Intra-and interobserver consistencies were calculated. The prevalence of femeroacetabular impingement (FAI) as a predisposing diagnosis resulting in end-stage degenerative joint disease treated with THA was determined. Results: The most common diagnosis was developmental dysplasia of the hip (DDH). The predisposing aetiologic factor leading to end-stage degenerative hip disease treated with THA was undetermined for 26 patients (2.6%). The number of patients who were diagnosed as cam-type FAI by all of the observers was 83, whereas it was 16 for pincer-type FAI. Interobserver agreement was very high in the evaluation of the stated ethiologies of hip osteoarthritis. The contingency coefficient for the diagnosis of FAI was 0.71 between observers. Conclusions: Our study may be a reference for further investigations to develop a better understanding of the underlying pathological factors in patients undergoing THA due to end-stage OA of the hip joint.