It is well known that the acetabular dysplasia results in hip pain that leads to the dysfunction of the hip that could later cause hip osteoarthritis. FAI can occur via external hip rotation as a result of a large anteversion, or via internal hip rotation and flexion as a result of a smaller anteversion of approximately 15° to 20°. The elevated inclination may result in a hypo-covered hip component, with the inclination angle determined to be between 40° and 45°. Inadequate anteversion and inclination can result in dislocation and femoro-acetabular impingement (FAI). Acetabular orientation is defined by two fundamental angles, anteversion and inclination, which are regarded as the most critical parameters for determining the quality of the total hip arthroplasty (THA). It has been suggested that acetabular orientation is a significant factor when diagnosing and treating hip pathology. These values reduce with growth, remaining in the 10-to-15-degree range for most adults but may be significantly different between populations or contralateral sides. The average range of anteversion at birth is from 30 to 40 degrees. Femoral anteversion occurs when the femoral neck axis is anteriorly rotated relative to the transcondylar axis and the femoral head axis is anterior to the femur coronal plane, and femoral retroversion occurs when the femoral head-neck axis points are posterior to the femoral coronal plane. The term femoral version refers to the orientation of the femoral neck in relation to the coronal or transcondylar axis of the distal femur. The EOS imaging system has a high correlation with CT for preoperative and postoperative/prosthetic hip measurements, with considerably lower irradiation of patients.
Average radiation dose for EOS was 0.18 ± 0.05 mGy for the anteroposterior view (AP) and 0.45 ± 0.08 mGy for the lateral view and for CT was 8.4 to 15.6 mGy. With respect to Pearson’s correlation between EOS and CT, the estimated average correlation for combined studies was significantly high (r = 0.86, 95% CI = 0.80 to 0.90, p-value < 0.001). Comparing EOS and CT, the estimated average correlation (effect size) for combined studies was significantly high (r = 0.84, 95% CI = 0.78 to 0.88, p-value < 0.001). The meta-analysis included five of these six studies (sample size from 20 to 90). The search retrieved 75 articles, six of which met inclusion and exclusion criteria. The amount of radiation dose between modalities was compared. For each meta-analysis, an effect size (average reliability coefficient) and a 95% confidence interval were calculated and presented in a forest plot. Reliability coefficients were transformed into Fisher’s Z to normalise their distribution and stabilise the variances. The heterogeneity exhibited by the effect sizes was obtained using a forest plot, the Q statistic and the I2 index. A narrative synthesis of the articles and a meta-analysis were conducted. Three reviewers independently assessed the quality of included studies using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) checklist.
Inclusion and exclusion criteria were developed according to the Population, Intervention, Comparator, Outcome (PICO) framework. Medline, Cochrane Systematic Review, and Web of Science databases were searched to obtain relevant articles published between January 1964 and February 2021. To determine the accuracy of the EOS imaging system compared to the gold standard computed tomography (CT) scan, for the measurement of native and postoperative/prosthetic hip parameters in adolescents and adults.