Background and objectives: Acetabular dysplasia is often characterized by acetabular bone hyperplasia and osteonecrosis of the femoral head. These pathological changes can alter the position of the center of the femoral head, causing abnormal values on anteroposterior radiographs of the adult pelvis involving the Wiberg anterior center-edge (CE) angle, acetabular angle (Sharp angle), and acetabular head index, eventually resulting in the inaccurate diagnosis of acetabular dysplasia. Herein, we introduce and verify three X-ray indicators, offshoring index (OFI), moving up index (MUI) and teardrop baseline offshoring index (TBOI). All data will be expressed as relative ratios, as we expect to make an accurate diagnosis by avoiding the generation of errors resulting from measurement angles. Design: A single-center, diagnostic trial. Methods: Two hundred adult patients (100 female and 100 male) will be scheduled to undergo pelvic X-ray examinations at the Third Hospital of Hebei Medical University in China. The affected and healthy sides will be measured and analyzed using commercial software. Outcome measures and preliminary results: The primary outcome measure is the sensitivity of OFI of the femoral head for diagnosing adult acetabular dysplasia. Secondary outcome measures include the specificity, positive and negative predictive values, and positive and negative likelihood ratios of OFI, and sensitivity specificity, positive and negative predictive values, and positive and negative likelihood ratios of MUI and TBOI of the femoral head for diagnosing adult acetabular dysplasia as well as the rate of correct diagnosis; correlation of OFI, MUI and TBOI to CE angle, Sharp angle and acetabular head index; and risk factors for hip dysfunction as analyzed by logistic regression analysis. In our pre-tests, pelvic X-ray data from 241 male patients showed that the OFI, MUI and TBOI were 86.8 ± 0.6%, 75.8 ± 2.0% and 76.2 ± 0.5%, which closely correlated with CE angle, Sharp angle, and acetabular head index (AHI). Discussion: This study is designed to verify that three new X-ray indicators, OFI, MUI and TBOI, as diagnostic indicators for adult acetabular dysplasia, can increase diagnostic accuracy and effectively avoid diagnostic errors in comparison with the CE angle, Sharp angle, and AHI. Ethics and dissemination: The study was approved by the Ethics Committee of the Third Hospital of Hebei Medical University in China (approval No. KE2016-011-1). The study will be performed in accordance with the relevant laws and regulations of the Declaration of Helsinki. All the participatns will be fully informed of the study protocol and experimental process, and provide written informed consent with the premise of fully understanding the treatment plan. The results of this study will be disseminated in peer-reviewed journals or presented at scientific meetings. Trial registrations: This trial was registered in the Chinese Clinical Trial Registry with registration number: ChiCTR1800016375 (protocol version: 1.0).
Read full abstract