title: Can 3D ultrasound identify trochlea dysplasia in newborns? Evaluation and applicability of a technique.
abstract: Femoro-patellar dysplasia is considered as a significant risk factor of patellar instability. Different studies suggest that the shape of the trochlea is already developed in early childhood. Therefore early identification of a dysplastic configuration might be relevant information for the treating physician. An easy applicable routine screening of the trochlea is yet not available. The purpose of this study was to establish and evaluate a screening method for femoro-patellar dysplasia using 3D ultrasound. From 2012 to 2013 we prospectively imaged 160 consecutive femoro-patellar joints in 80 newborns from the 36th to 61st gestational week that underwent a routine hip sonography (Graf). All ultrasounds were performed by a pediatric radiologist with only minimal additional time to the routine hip ultrasound. In 30° flexion of the knee, axial, coronal, and sagittal reformats were used to standardize a reconstructed axial plane through the femoral condyle and the mid-patella. The sulcus angle, the lateral-to-medial facet ratio of the trochlea and the shape of the patella (Wiberg Classification) were evaluated. In all examinations reconstruction of the standardized axial plane was achieved, the mean trochlea angle was 149.1° (SD 4.9°), the lateral-to-medial facet ratio of the trochlea ratio was 1.3 (SD 0.22), and a Wiberg type I patella was found in 95% of the newborn. No statistical difference was detected between boys and girls. Using standardized reconstructions of the axial plane allows measurements to be made with lower operator dependency and higher accuracy in a short time. Therefore 3D ultrasound is an easy applicable and powerful tool to identify trochlea dysplasia in newborns and might be used for screening for trochlea dysplasia.
authors.affiliation: Clinic for Orthopedics and Trauma Surgery, University Hospital Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany. Electronic address: Hendrik.Kohlhof@ukb.uni-bonn.de.
authors.forename: Hendrik
authors.initials: H
authors.lastname: Kohlhof
authors.affiliation: Department of Orthopedic Surgery, University Children's Hospital Zurich, Steinwiesstrasse 74, 8032 Switzerland. Electronic address: Christoph.heidt@kispi.uzh.ch.
authors.forename: Christoph
authors.initials: C
authors.lastname: Heidt
authors.affiliation: Department of Pediatric Radiology, University Children's Hospital Berne, Freiburgstrasse 18, 3010 Berne, Switzerland. Electronic address: Alexandrine.baehler@insel.ch.
authors.forename: Alexandrine
authors.initials: A
authors.lastname: Bähler
authors.affiliation: Department of Orthopedic Surgery, University Hospital Berne, Freiburgstrasse 18, 3010 Berne, Switzerland. Electronic address: sandro.kohl@insel.ch.
authors.forename: Sandro
authors.initials: S
authors.lastname: Kohl
authors.affiliation: Clinic for Orthopedics and Trauma Surgery, University Hospital Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany. Electronic address: sascha.gravius@ukb.uni-bonn.de.
authors.forename: Sascha
authors.initials: S
authors.lastname: Gravius
authors.affiliation: Clinic for Orthopedics and Trauma Surgery, University Hospital Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany. Electronic address: Max.Friedrich@ukb.uni-bonn.de.
authors.forename: Max J
authors.initials: MJ
authors.lastname: Friedrich
authors.affiliation: Department of Orthopedic Surgery, University Hospital Berne, Freiburgstrasse 18, 3010 Berne, Switzerland. Electronic address: kai.ziebarth@insel.ch.
authors.forename: Kai
authors.initials: K
authors.lastname: Ziebarth
authors.affiliation: Department of Pediatric Radiology, University Children's Hospital Berne, Freiburgstrasse 18, 3010 Berne, Switzerland. Electronic address: Enno.Stranzinger@insel.ch.
authors.forename: Enno
authors.initials: E
authors.lastname: Stranzinger
mesh_terms: D005260:Female; D005269:Femur / Q000000981:diagnostic imaging*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007231:Infant, Newborn; D007593:Joint Instability / Q000000981:diagnostic imaging* / Q000601:surgery; D007719:Knee Joint / Q000000981:diagnostic imaging*; D008297:Male; D010329:Patella / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D012307:Risk Factors; D014463:Ultrasonography
keywords: Children; Patellar instability; Screening; Trochlea dysplasia; Ultrasound