title: DXA in the assessment of subchondral bone mineral density in knee osteoarthritis--A semi-standardized protocol after systematic review.
abstract: BACKGROUND
  Subchondral bone mineral density (sBMD) contributes to the initiation and progression of knee osteoarthritis (OA). Reliable methods to assess sBMD status may predict the response of specific OA phenotypes to targeted therapies. While dual-energy X-ray absorptiometry (DXA) of the knee can determine sBMD, no consensus exists regarding its methodology.
  
  
  OBJECTIVE
  Construct a semi-standardized protocol for knee DXA to measure sBMD in patients with OA of the knee by evaluating the varying methodologies present in existing literature.
  
  
  METHODS
  We performed a systematic review of original papers published in PubMed and Web of Science from their inception to July 2014 using the following search terms: subchondral bone, osteoarthritis, and bone mineral density.
  
  
  RESULTS
  DXA of the knee can be performed with similar reproducibility values to those proposed by the International Society for Clinical Densitometry for the hip and spine. We identified acquisition view, hip rotation, knee positioning and stabilization, ROI location and definition, and the type of analysis software as important sources of variation. A proposed knee DXA protocol was constructed taking into consideration the results of the review.
  
  
  CONCLUSIONS
  DXA of the knee can be reliably performed in patients with knee OA. Nevertheless, we found substantial methodological variation across previous studies. Methodological standardization may provide a foundation from which to establish DXA of the knee as a valid tool for identification of SB changes and as an outcome measure in clinical trials of disease modifying osteoarthritic drugs.
authors.affiliation: Rheumatology Department, CHLO-Hospital Egas Moniz, Lisbon, Portugal; Chronic Diseases Study Center (CEDOC), NOVA Medical School, UNL, Lisbon, Portugal.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Sepriano
authors.affiliation: Bone and Joint Research Unit, IIS Fundación Jiménez Díaz, Universidad Autónoma, Av. Reyes Católicos 2, 28040 Madrid, Spain.
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Roman-Blas
authors.affiliation: Bone and Joint Research Unit, IIS Fundación Jiménez Díaz, Universidad Autónoma, Av. Reyes Católicos 2, 28040 Madrid, Spain; Faculty of Medicine, Nursing & Health Sciences, Monash University, Melbourne, Australia.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Little
authors.affiliation: Rheumatology Department, CHLO-Hospital Egas Moniz, Lisbon, Portugal; Chronic Diseases Study Center (CEDOC), NOVA Medical School, UNL, Lisbon, Portugal.
authors.forename: Fernando
authors.initials: F
authors.lastname: Pimentel-Santos
authors.affiliation: Bone and Joint Research Unit, IIS Fundación Jiménez Díaz, Universidad Autónoma, Av. Reyes Católicos 2, 28040 Madrid, Spain.
authors.forename: Jose María
authors.initials: JM
authors.lastname: Arribas
authors.affiliation: Bone and Joint Research Unit, IIS Fundación Jiménez Díaz, Universidad Autónoma, Av. Reyes Católicos 2, 28040 Madrid, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Largo
authors.affiliation: Rheumatology Department, CHLO-Hospital Egas Moniz, Lisbon, Portugal; Chronic Diseases Study Center (CEDOC), NOVA Medical School, UNL, Lisbon, Portugal.
authors.forename: Jaime C
authors.initials: JC
authors.lastname: Branco
authors.affiliation: Bone and Joint Research Unit, IIS Fundación Jiménez Díaz, Universidad Autónoma, Av. Reyes Católicos 2, 28040 Madrid, Spain. Electronic address: gherrero@fjd.es.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Herrero-Beaumont
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods*; D002358:Cartilage, Articular / Q000000981:diagnostic imaging; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging*; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D000078202:Systematic Reviews as Topic
keywords: Bone mineral density; Knee osteoarthritis; Subchondral bone