title: Does repeated palpation-digitization of pelvic landmarks for measurement of innominate motion introduce a systematic error?--A psychometric investigation.
abstract: BACKGROUND
  Palpation-digitization technique for measurement of innominate motion involves repeated manual palpation-digitization of pelvic landmarks, which could introduce a systematic variation between subsequent trials and thereby influence final innominate angular measurement.
  
  
  OBJECTIVE
  The aim of this study is to quantify the effect of repeated palpation-digitization errors on overall variability of innominate vector length measurements; and to determine if there is a systematic variation between subsequent repeated trials.
  
  
  METHODS
  A single group repeated measures study, using four testers and fourteen healthy participants, was conducted. Four pelvic landmarks, left and right posterior superior iliac spine and anterior superior iliac spine, were palpated and digitized using 3D digitizing stylus of Polhemus electromagnetic tracking device, for ten consecutive trials by each tester in their random order. The ten individual trials of innominate vector lengths measured by each tester for each participant were used for the analysis.
  
  
  CONCLUSIONS
  Repeated measures ANOVA demonstrated a very small effect of repeated trial factor (≤0.66%) as well as error component (≤0.32%) on innominate vector length variability. Further, residual versus order plots demonstrated a random pattern of errors across zero; thus indicating no systematic variation between subsequent trials of innominate vector length measurements.
authors.affiliation: School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand; School of Physiotherapy, University of Otago, Dunedin, New Zealand. Electronic address: divya.adhia@otago.ac.nz.
authors.forename: Divya Bharatkumar
authors.initials: DB
authors.lastname: Adhia
authors.affiliation: School of Physiotherapy, University of Otago, Dunedin, New Zealand.
authors.forename: Ramakrishnan
authors.initials: R
authors.lastname: Mani
authors.affiliation: School of Physiotherapy, University of Otago, Dunedin, New Zealand.
authors.forename: Stephan
authors.initials: S
authors.lastname: Milosavljevic
authors.affiliation: School of Physiotherapy, University of Otago, Dunedin, New Zealand.
authors.forename: Steve
authors.initials: S
authors.lastname: Tumilty
authors.affiliation: School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand.
authors.forename: Melanie D
authors.initials: MD
authors.lastname: Bussey
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D019300:Medical Errors / Q000517:prevention & control*; D010173:Palpation / Q000379:methods*; D017699:Pelvic Pain / Q000628:therapy*; D010388:Pelvis / Q000502:physiology* / Q000503:physiopathology*; D011594:Psychometrics; D016059:Range of Motion, Articular / Q000502:physiology*; D015203:Reproducibility of Results
keywords: Errors; Movement; Palpation-digitization; Sacroiliac joint