title: Can ultrasound of plantar plate have normal appearance with a positive drawer test?
abstract: OBJECTIVE
  The aims of this study were (1) to evaluate the reliability of ultrasound (US) examination in the identification and measurement of the metatarsophalangeal plantar plate (MTP-PP) in asymptomatic subjects and (2) to establish the correlation of US findings with those of physical examination and magnetic resonance imaging (MRI), once it is an important tool in the evaluation of the instability syndrome of the second and third rays.
  
  
  METHODS
  US examinations of the second and third MTP-PPs were performed in eight asymptomatic volunteers, totaling 32 MTP joints, by three examiners with different levels of experience in musculoskeletal US. Plantar plate dimensions, integrity and echogenicity, the presence of ruptures, and confidence level in terms of structure identification were determined using conventional US. Vascular flow was assessed using power Doppler. US data were correlated with data from physical examination and MRI.
  
  
  RESULTS
  MTP-PPs were ultrasonographically identified in 100% of cases, always showing homogeneous hyperechoic features and no detectable vascular flow on power Doppler, with 100% certainty in identification for all examiners. There was excellent US inter-observer agreement for longitudinal measures of second and third toe MTP-PPs and for transverse measures of the second toe MTP-PP. The MTP drawer test was positive for grade 1 MTP instability in 34.4% of joints with normal US results. Transverse MTP-PP measures were significantly higher in individuals with positive MTP drawer test. US measures and characteristics of MPT-PPs were positively correlated with those of MRI.
  
  
  CONCLUSIONS
  US is efficient in identifying and measuring MPT-PPs and may complement physical examination. A grade 1 positive MTP drawer test may be found in asymptomatic individuals with normal MPT-PPs, as assessed by imaging.
authors.affiliation: Affiliated Professor, Department of Diagnostic Imaging, Escola Paulista de Medicina, Universidade Federal de São Paulo (EPM-Unifesp), São Paulo, Brazil.
authors.forename: Eloy de Avila
authors.initials: EA
authors.lastname: Fernandes
authors.affiliation: Medical Assistant of Medicine and Surgery of the Foot and Ankle Group, Department of Orthopedics and Traumatology, EPM-Unifesp, São Paulo, Brazil.
authors.forename: Tania Szejnfeld
authors.initials: TS
authors.lastname: Mann
authors.affiliation: Professor and Coordinator of Educational and Research Support, Department of Diagnostic Imaging, EPM-Unifesp, São Paulo, Brazil. Electronic address: andrea.ddi@epm.br.
authors.forename: Andrea
authors.initials: A
authors.lastname: Puchnick
authors.affiliation: Postgraduate Physician, Department of Diagnostic Imaging, EPM-Unifesp, São Paulo, Brazil.
authors.forename: Franklin de Freitas
authors.initials: FF
authors.lastname: Tertulino
authors.affiliation: Resident Physician, Department of Surgery, EPM-Unifesp, São Paulo, Brazil.
authors.forename: Camila Testoni
authors.initials: CT
authors.lastname: Cannato
authors.affiliation: Associate Professor, Department of Orthopedics and Traumatology, EPM-Unifesp, São Paulo, Brazil.
authors.forename: Caio
authors.initials: C
authors.lastname: Nery
authors.affiliation: Associate Professor, Department of Diagnostic Imaging, EPM-Unifesp, São Paulo, Brazil.
authors.forename: Artur da Rocha Corrêa
authors.initials: ADRC
authors.lastname: Fernandes
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008683:Metatarsophalangeal Joint / Q000000981:diagnostic imaging* / Q000293:injuries / Q000473:pathology; D010808:Physical Examination; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography
keywords: Magnetic resonance imaging; Metatarsalgia; Metatarsophalangeal joint; Metatarsophalangeal plantar plate; Ultrasound