Validity and reliability of palpation-digitization for non-invasive kinematic measurement - a systematic review

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.