title: The validity of a non-radiologist reader in identifying cam and pincer femoroacetabular impingement (FAI) using plain radiography.
abstract: The purpose of this study was to evaluate the validity and reliability of a radiographic diagnosis of femoroacetabular impingement (FAI) by a non-radiologist. Symptomatic FAI is prevalent and thought to be a cause of hip osteoarthritis. However, the diagnosis is often delayed by 1-2 years, in large part because radiographic findings are often subtle and clinicians have been unaware of their significance. The purpose of this study was to evaluate the validity of a radiographic diagnosis of FAI by a non-radiologist. A population-based sample of 701 subjects was recruited in Vancouver, Canada. For the current study, 50 subjects were selected-40 randomly from the population sample and 10 from an orthopedic practice with confirmed FAI. An anterior-posterior pelvis and bilateral Dunn radiographs were acquired and read by a fellowship-trained musculoskeletal radiologist and a third-year medical student who received basic training in radiographic signs of FAI. Three radiographic signs were evaluated: the lateral center edge angle, alpha angle and crossover sign. Validity was assessed using sensitivity and specificity, Bland-Altman limits of agreement and kappa. The sample contained 65% women (n = 31), was 62% Caucasian and 38% Chinese and had a mean age of 38.3 years. For correctly diagnosing FAI, the non-radiologist reader had a sensitivity of 0.83 and specificity of 0.87. Intra-rater κ value was 0.72, and prevalence-adjusted bias-adjusted κ was 0.76. This study provides evidence that a non-radiologist can accurately and reliably identify FAI on plain films.
authors.affiliation: Arthritis Research Centre of Canada, 5591 No. 3 Road, Richmond, BC, V6X 2C7, Canada. drcrat@gmail.com.|Brigham and Women's Hosp., Harvard Medical School, Boston, MA, USA. drcrat@gmail.com.
authors.forename: C
authors.identifier: http://orcid.org/0000-0002-0698-9871
authors.initials: C
authors.lastname: Ratzlaff
authors.affiliation: University of British Columbia, Vancouver, BC, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Zhang
authors.affiliation: University of British Columbia, Vancouver, BC, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Korzan
authors.affiliation: University of British Columbia, Vancouver, BC, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Josey
authors.affiliation: University of British Columbia, Vancouver, BC, Canada.
authors.forename: H
authors.initials: H
authors.lastname: Wong
authors.affiliation: University of British Columbia, Vancouver, BC, Canada.|Arthritis Research Centre of Canada, 5591 No. 3 Road, Richmond, BC, V6X 2C7, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Cibere
authors.affiliation: Arthritis Research Centre of Canada, 5591 No. 3 Road, Richmond, BC, V6X 2C7, Canada.
authors.forename: H M
authors.initials: HM
authors.lastname: Prlic
authors.affiliation: University of British Columbia, Vancouver, BC, Canada.|Arthritis Research Centre of Canada, 5591 No. 3 Road, Richmond, BC, V6X 2C7, Canada.
authors.forename: J A
authors.initials: JA
authors.lastname: Kopec
authors.affiliation: University of British Columbia, Vancouver, BC, Canada.|Arthritis Research Centre of Canada, 5591 No. 3 Road, Richmond, BC, V6X 2C7, Canada.
authors.forename: J M
authors.initials: JM
authors.lastname: Esdaile
authors.affiliation: University of British Columbia, Vancouver, BC, Canada.|Arthritis Research Centre of Canada, 5591 No. 3 Road, Richmond, BC, V6X 2C7, Canada.
authors.forename: L C
authors.initials: LC
authors.lastname: Li
authors.affiliation: Arthritis Research Centre of Canada, 5591 No. 3 Road, Richmond, BC, V6X 2C7, Canada. mbarber@arthritisresearch.ca.
authors.forename: M
authors.initials: M
authors.lastname: Barber
authors.affiliation: University of British Columbia, Vancouver, BC, Canada.|Vancouver General Hospital, Vancouver, BC, Canada.
authors.forename: B B
authors.initials: BB
authors.lastname: Forster
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging*; D000328:Adult; D059925:Anatomic Landmarks; D001955:British Columbia; D002983:Clinical Competence; D005260:Female; D057925:Femoracetabular Impingement / Q000000981:diagnostic imaging*; D005269:Femur / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results
keywords: Femoroacetabular impingement; Hip osteoarthritis; Hip radiography; Validation