Reliability of clinical measurement of subtalar joint movement

This study was designed to evaluate the intra- and interexaminer reliability during repeated clinical measurements of subtalar movement. The study was a blinded experimental model in which 11 Royal College certified orthopaedic surgeons measured the subtalar movement of the 10 lower extremities of five normal subjects. The measurements were performed in accordance with previously published recommendations. Measurements of both inversion and eversion were recorded in degrees. Employing a variance component analysis, a coefficient of agreement between examiner measures was established. The coefficient of agreements were 0.107 for right lower extremities and 0.0656 for left lower extremities. An evaluation of means and ranges of individual examiner measures demonstrated a potential average loss of range of motion of 20% simply because of variability in measurement. It was also determined that a learning curve did not exist within examiners in this study. The reliability of clinical estimates of subtalar movement by this method is extremely poor. Both inter- and intraexaminer reliability are so poor as to suggest that this method of examination no longer be used to determine or document the measurement of subtalar movement.