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Background Electromagnetic palpation-digitization technique for measurement of innominate motion involves calculation of innominate rotation using the innominate vector length in the neutral (NEUT) and combined hip abduction and external rotation (HABER) test positions. The innominate vector length [i.e., the segment between anterior superior iliac spine (ASIS) and posterior superior iliac spine (PSIS)] is not a rigid structure and its deformation could introduce an error influencing the final innominate rotation measurement. Objectives The aim of this study is to determine if there is significant deformation occurring in innominate vector length when the hip is loaded into the HABER test position. Method A cross sectional study using sixteen healthy individuals and a single tester was conducted. Four pelvic landmarks, left and right PSIS and ASIS, were palpated and digitized using 3D digitizing stylus of Polhemus electromagnetic tracking device, in two hip test positions, NEUT and 50° HABER. The innominate vector lengths were calculated from the 3D coordinates of pelvic landmarks, for each hip test positions. Results and conclusion Paired t-tests demonstrated no significant differences (p > 0.05) in the innominate vector lengths at the side of the load as well as the opposite innominate when either the right or left hip was loaded; thus indicating no significant bone deformation in innominate segment during the HABER test position. [ABSTRACT FROM AUTHOR]

Abstract: Joint kinematic assessment using an electromagnetic tracking device (EMTD) requires palpation-digitization (PD) of bony landmarks to define the anatomical axes. Errors in PD of bony landmarks can perturb the anatomical axes and affect the validity and reliability of kinematic measurements. The validity and reliability of PD for kinematic measurement needs to be explored before recommending its wider use. A systematic search of 15 electronic databases located studies assessing validity and/or reliability of PD for joint kinematic assessment. Two independent reviewers used the QUADAS and QAREL tools to assess quality of validity and reliability studies respectively. The results were synthesized qualitatively using a level of evidence approach. Eight studies satisfied the final eligibility criteria and were included in the review. The validity, intra-rater reliability and inter-rater reliability were assessed in three, seven and one study respectively. The overall level of evidence for validity of PD technique was strong with high correlation (≥0.80) reported by three high (≥60%) quality studies. The overall level of evidence for intra-rater reliability was also strong with very high ICC (≥0.90) and satisfactory SEM (SEM% ≤ 10%) reported by four high quality studies. However the level of evidence for inter-rater reliability was limited and needs to be addressed by future research. [Copyright &y& Elsevier]

Abstract: Although the complex anatomical orientation and position of the sacroiliac joints (SIJ) has rendered their 3D kinematic evaluation difficult, recent techniques of palpation–digitization of pelvic landmarks using electromagnetic tracking device have been able to accurately and non-invasively quantify the subtle SIJ kinematics. While this technique demonstrates radiographic validity and high test-retest reliability, it is yet to be assessed with regards to inter-tester and trial-to-trial reliability. A single-group repeated measure design using 4 testers was conducted to evaluate the inter-tester and trial-to-trial reliability of palpation–digitization technique for innominate vector length measurements using the Polhemus electromagnetic tracking device. Fourteen young, healthy adults between the ages of 18–40 years participated in the study. The innominate vector length was calculated from 3D co-ordinates of palpated and digitized pelvic landmarks in two test positions of hip. A sensitivity analysis was conducted to determine how palpation–digitization errors for pelvic landmarks impacts on innominate angle calculation. Reliability indexes of Intraclass correlation coefficient (ICC) (≥0.97) and Standard error of measurement (SEM) (≤2.02 mm) demonstrated very high inter-tester and trial-to-trial reliability and accuracy of palpation–digitization technique for innominate vector length measurements, irrespective of the two test positions. A higher consistency of measurements was obtained within-testers as compared to between testers, and sensitivity analysis demonstrated a negligible influence of palpation–digitization errors on the innominate angle measurements. The results support clinical and research utility of this technique for non-invasive kinematic evaluation of SIJ motion for this population. Further research on the use of this palpation–digitization technique in symptomatic population is warranted. [Copyright &y& Elsevier]