title: Sensitivity of standing radiographs to detect knee arthritis: a systematic review of Level I studies.
abstract: OBJECTIVE
  The purpose of this study was to perform a systematic review of the available literature to define the level of quality evidence for determining the sensitivity and specificity of different radiographic views in detecting knee osteoarthritis and to determine the impact of different grading systems on the ability to detect knee osteoarthritis.
  
  
  METHODS
  A systematic review of the literature was conducted to identify studies that evaluated the standing anteroposterior (AP) and 45° posteroanterior (PA) views for tibiofemoral and patellofemoral arthritis and those comparing the use of the Kellgren-Lawrence versus the joint space narrowing (JSN) radiographic grading systems using arthroscopy as the gold standard. A comprehensive search of PubMed, Scopus, CINAHL, the Cochrane Database, Clinicaltrial.gov, and EMBASE was performed using the keywords "osteoarthritis," "knee," "x-ray," "sensitivity," and "arthroscopy."
  
  
  RESULTS
  Six studies were included in the evaluation. The 45° flexion PA view showed a higher sensitivity than the standing AP view for detecting severe arthritis involving either the medial or lateral tibiofemoral compartment. There was no difference in the specificities for the 2 views. The direct comparison of the Kellgren-Lawrence and the JSN radiographic grading systems found no clinical difference between the 2 systems regarding the sensitivities, although the specificity was greater for the JSN system.
  
  
  CONCLUSIONS
  The ability to detect knee osteoarthritis continues to be difficult without using advanced imaging. However, as an inexpensive screening tool, the 45° flexion PA view is more sensitive than the standing AP view to detect severe tibiofemoral osteoarthritis. When evaluating the radiograph for severe osteoarthritis using either the Kellgren-Lawrence or JSN grading system, there is no clinical difference in the sensitivity between the 2 methods; however, the JSN may be more specific for ruling in severe osteoarthritis in the medial compartment.
  
  
  METHODS
  Level I, systematic review of Level I studies.
authors.affiliation: Department of Orthopaedic Surgery and Sports Medicine, University of Kentucky, Lexington, Kentucky, U.S.A.. Electronic address: stdunc2@uky.edu.
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Duncan
authors.affiliation: Department of Orthopaedic Surgery, UT Southwestern Medical Center, Dallas, Texas, U.S.A.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Khazzam
authors.affiliation: Department of Orthopaedic Surgery and Sports Medicine, University of Kentucky, Lexington, Kentucky, U.S.A.
authors.forename: Jeremy M
authors.initials: JM
authors.lastname: Burnham
authors.affiliation: Department of Orthopaedic Surgery, Cleveland Clinic Sports Health Center, Cleveland, Ohio, U.S.A.
authors.forename: Kurt P
authors.initials: KP
authors.lastname: Spindler
authors.affiliation: Department of Orthopedics and Rehabilitation, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, U.S.A.
authors.forename: Warren R
authors.initials: WR
authors.lastname: Dunn
authors.affiliation: Department of Orthopaedic Surgery, Washington University School of Medicine at Barnes-Jewish Hospital, St. Louis, Missouri, U.S.A.
authors.forename: Rick W
authors.initials: RW
authors.lastname: Wright
mesh_terms: D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging*; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging*; D011187:Posture; D011859:Radiography; D012680:Sensitivity and Specificity