title: Evaluating the acromion marker cluster as a method for measuring scapular orientation in children with brachial plexus birth palsy.
abstract: Several studies have described using an acromion marker cluster for measuring scapular orientation in healthy adults performing planar motions. It is unknown whether the acromion marker cluster method will provide the same level of accuracy in children with brachial plexus birth palsy. This study compared this method to palpation for calculating scapular orientation in children with brachial plexus birth palsy performing clinically relevant movements. Scapular orientation in ten patients was determined by palpation and an acromion marker cluster in neutral and six Modified Mallet positions. RMSEs and mean relative errors were calculated. Resultant RMSEs ranged from 5.2 degrees to 21.4 degrees. The averages of the mean relative errors across all positions for each axis were 177.4% for upward/downward rotation, 865.0% for internal/external rotation, and 166.2% for anterior/posterior tilt. The acromion marker cluster method did not accurately measure scapular rotation relative to the total movement on an individual or group basis in the population. With most relative errors over 100%, the acromion marker cluster method often produced errors larger than the actual measured motion. The accuracy of the acromion marker cluster method limits its use as a clinical tool for measuring scapular kinematics on children with brachial plexus birth palsy.
authors.affiliation: Biomechanics and Movement Science Program, University of Delaware, Newark, DE.
authors.forename: Kristen F
authors.initials: KF
authors.lastname: Nicholson
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Russo
authors.forename: Scott H
authors.initials: SH
authors.lastname: Kozin
authors.forename: Dan A
authors.initials: DA
authors.lastname: Zlotolow
authors.forename: Robert L
authors.initials: RL
authors.lastname: Hulbert
authors.forename: K Michael
authors.initials: KM
authors.lastname: Rowley
authors.forename: James G
authors.initials: JG
authors.lastname: Richards
mesh_terms: D000174:Acromion / Q000473:pathology*; D000293:Adolescent; D059925:Anatomic Landmarks / Q000473:pathology*; D020516:Brachial Plexus Neuropathies / Q000151:congenital / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008297:Male; D010173:Palpation / Q000379:methods*; D010243:Paralysis / Q000151:congenital / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012785:Shoulder Joint / Q000473:pathology*; D051598:Whole Body Imaging / Q000379:methods