Correlation between borderline acetabular dysplasia and hip osteoarthritis: A retrospective cross-sectional radiographic study

Introduction: Hip osteoarthritis is one of the most prevalent diseases commonly affect older patients. It is also one of the most common causes of functional disability and musculoskeletal pain, but about half of the OA patients do not complain about these symptoms and remain undiagnosed. The aim of this study is to compare the radiological findings of OA with the acetabular dysplasia in patients who have not been diagnosed with OA before.

Methods: 365 patients (200 males, 165 females) aged between 40 and 65 were included in the study. Data were obtained retrospectively, among abdominal and pelvic Computerized Tomographies (CT) of patients consulted in urology department of our hospital with urological complaints. AP Topogram of each patient’s CT’s was evaluated. Center-Edge Angle (CEA), Acetabular Angle (Sharp Angle-SA) were measured and Tönnis Grading of each hip were calculated. Correlation between CEA and SA measurements and Tönnis Grading (grade 0, grade 1 and grade 2) of hip OA were evaluated.

Results: Overall, 8.63% (7.25% in males and 10.30% in females) of the patients had AD, based on at least one of the measurements (CEA<25° or SA>42°). Rate of hip OA was found as 8% in males and 6.36% in females (overall 7.26%). Mean CEA was 35.06° (± 5.58) in males and 34.71° (± 5.91) in females (overall 34.90° (± 5.73). Mean SA was 37.23° (± 2.92) in males and 37.75° (± 3.54) in females (overall 37.46° (± 3.22). There were no significant difference between Tönnis grades 0,1 and 2 groups, with respect to mean CEA and SA rates (p<0.27). The rate of Tönnis grade 2 OA was significantly higher in dysplastic group based on <25 CEA values, but there was no correlation between the hip OA and AD based on >42° SA values (p=0.32). So; unlike SA, CEA seems to have a role in etiology of the hip OA.

Conclusion: This study has provided prevalence values of CEA and SA in patients with radiologic evidence of hip osteoarthritis. AD; based on CEA, but not SA is correlated with radiographic findings of hip OA.

Level of evidence: IV, retrospective series.