Detection of femoroplasty on pre- and post-arthroscopic comparison radiographs following treatment of femoroacetabular impingement syndrome: multi-reader accuracy and agreement study

Objective To assess diagnostic accuracy and agreement among radiologists in detecting femoroplasty on pre- and post-arthroscopic comparison frog lateral and anteroposterior (AP) pelvic radiographs after treatment of femoroacetabular impingement (FAI) syndrome. Materials and methods In this retrospective, cross-sectional study, 86 patients underwent hip arthroscopy (52 with and 34 without femoroplasty) for treatment of FAI syndrome. Three radiologists blinded to clinical data and chronological order of the pre- and post-arthroscopic comparison radiographs independently examined AP pelvis and frog lateral radiographs to detect femoroplasty changes. Statistical analysis outputs included diagnostic accuracy parameters and inter- and intra-observer agreement. Results Identification of femoroplasty in the frog lateral projection has mean sensitivity 70%, specificity 82%, inter-observer agreement κ 0.74–0.76 and intra-observer agreement κ 0.72–0.85. Using the AP pelvis projection to detect femoroplasty has mean sensitivity 32%, specificity 71%, inter-observer agreement κ 0.47–0.65, and intra-observer agreement κ, 0.56–0.84. Conclusions Radiologists are only moderately sensitive, though more specific, in femoroplasty detection in the frog lateral projection. The AP pelvis projection yields lower sensitivity and specificity. Both projections have moderate inter- and intra-observer agreement.