Diagnosing Femoroacetabular Impingement From Plain Radiographs: Do Radiologists and Orthopaedic Surgeons Differ?

Background:A diagnosis of femoroacetabular impingement (FAI) requires careful history and physical examination, as well as an accurate and reliable radiologic evaluation using plain radiographs as a screening modality. Radiographic markers in the diagnosis of FAI are numerous and not fully validated. In particular, reliability in their assessment across health care providers is unclear.Purpose:To determine inter- and intraobserver reliability between orthopaedic surgeons and musculoskeletal radiologists.Study Design:Cohort study (diagnosis); Level of evidence, 3.Methods:Six physicians (3 orthopaedic surgeons, 3 musculoskeletal radiologists) independently evaluated a broad spectrum of FAI pathologies across 51 hip radiographs on 2 occasions separated by at least 4 weeks. Reviewers used 8 common criteria to diagnose FAI, including (1) pistol-grip deformity, (2) size of alpha angle, (3) femoral head-neck offset, (4) posterior wall sign abnormality, (5) ischial spine sign abnormality, (6) coxa profunda abnorm...