title: Which patellofemoral joint imaging features are associated with patellofemoral pain? Systematic review and meta-analysis.
abstract: OBJECTIVE
  To review the association between patellofemoral joint (PFJ) imaging features and patellofemoral pain (PFP).
  
  
  METHODS
  A systematic review of the literature from AMED, CiNAHL, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PEDro, EMBASE and SPORTDiscus was undertaken from their inception to September 2014. Studies were eligible if they used magnetic resonance imaging (MRI), computed tomography (CT), ultrasound (US) or X-ray (XR) to compare PFJ features between a PFP group and an asymptomatic control group in people <45 years of age. A pooled meta-analysis was conducted and data was interpreted using a best evidence synthesis.
  
  
  RESULTS
  Forty studies (all moderate to high quality) describing 1043 people with PFP and 839 controls were included. Two features were deemed to have a large standardised mean difference (SMD) based on meta-analysis: an increased MRI bisect offset at 0° knee flexion under load (0.99; 95% CI: 0.49, 1.49) and an increased CT congruence angle at 15° knee flexion, both under load (1.40 95% CI: 0.04, 2.76) and without load (1.24; 95% CI: 0.37, 2.12). A medium SMD was identified for MRI patella tilt and patellofemoral contact area. Limited evidence was found to support the association of other imaging features with PFP. A sensitivity analysis showed an increase in the SMD for patella bisect offset at 0° knee flexion (1.91; 95% CI: 1.31, 2.52) and patella tilt at 0° knee flexion (0.99; 95% CI: 0.47, 1.52) under full weight bearing.
  
  
  CONCLUSIONS
  Certain PFJ imaging features were associated with PFP. Future interventional strategies may be targeted at these features.
  CRD 42014009503.
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, UK; NIHR Leeds Musculoskeletal Biomedical Research Unit, Leeds, UK.
authors.forename: B T
authors.initials: BT
authors.lastname: Drew
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, UK; NIHR Leeds Musculoskeletal Biomedical Research Unit, Leeds, UK.
authors.forename: A C
authors.initials: AC
authors.lastname: Redmond
authors.affiliation: School of Health Sciences, University of East Anglia, Norwich, UK.
authors.forename: T O
authors.initials: TO
authors.lastname: Smith
authors.affiliation: Physiotherapy Department, Norfolk and Norwich University Hospitals NHS Foundation Trust, Norwich, UK.
authors.forename: F
authors.initials: F
authors.lastname: Penny
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, UK; NIHR Leeds Musculoskeletal Biomedical Research Unit, Leeds, UK. Electronic address: p.conaghan@leeds.ac.uk.
authors.forename: P G
authors.initials: PG
authors.lastname: Conaghan
mesh_terms: D006801:Humans; D008279:Magnetic Resonance Imaging; D057071:Patellofemoral Joint / Q000000981:diagnostic imaging / Q000473:pathology*; D046788:Patellofemoral Pain Syndrome / Q000000981:diagnostic imaging / Q000473:pathology*; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
keywords: Diagnostic imaging; Magnetic resonance imaging; Patellofemoral pain; Systematic review