“The accuracy of the EOS imaging system to assess hip abnormalities in adolescents and adults:” a systematic review and meta-analysis

Objectives 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. Methods Medline, Cochrane Systematic Review, and Web of Science databases were searched to obtain relevant articles published between January 1964 and February 2021. All articles published in English. Inclusion and exclusion criteria were developed according to the Population, Intervention, Comparator, Outcome (PICO) framework. Three reviewers independently assessed the quality of included studies using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) checklist. A narrative synthesis of the articles and a meta-analysis were conducted. The heterogeneity exhibited by the effect sizes was obtained using a forest plot, the Q statistic and the I2 index. Reliability coefficients were transformed into Fisher’s Z to normalise their distribution and stabilise the variances. For each meta-analysis, an effect size (average reliability coefficient) and a 95% confidence interval were calculated and presented in a forest plot. The amount of radiation dose between modalities was compared. Results The search retrieved 75 articles, six of which met inclusion and exclusion criteria. The meta-analysis included five of these six studies (sample size from 20 to 90). 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). 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). 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. Conclusion The EOS imaging system has a high correlation with CT for preoperative and postoperative/prosthetic hip measurements, with considerably lower irradiation of patients.