Reliability of first ray position and mobility measurements in experienced and inexperienced examiners.

CONTEXT Neither reliability nor validity data exist for the Root method of clinically assessing first ray position or mobility by experienced and inexperienced examiners. OBJECTIVE To determine intrarater and interrater reliability for first ray position and mobility measurements in experienced and inexperienced examiners. DESIGN Single-blind prospective reliability study. SETTING Physical therapy clinic. PATIENTS OR OTHER PARTICIPANTS Four examiners, 2 experienced and 2 inexperienced, obtained first ray position and mobility measurements. Both feet of 36 subjects (14 males, 22 females) were measured. INTERVENTION(S) Each examiner evaluated first ray position and mobility for each of the subjects' feet on 2 separate occasions using the manual assessment techniques described by Root. MAIN OUTCOME MEASURE(S) First ray position (normal, plantar flexed, dorsiflexed) and mobility (normal, hypermobile, hypomobile) decisions were made. RESULTS We calculated kappa correlation coefficients for intrarater and interrater reliability. For position, intrarater and interrater reliability ranged from .03 to .27 for all examiners, experienced and inexperienced. For mobility, intrarater and interrater reliability ranged from .02 to .26 for experienced, inexperienced, and experienced/inexperienced. The percentage agreement (P(O)) values for all examiners were less than 58%. For individual values for position, intrarater and interrater reliability ranged from .00 to .26. For individual values for mobility, intrarater and interrater reliability ranged from .00 to .26. The P(O) values for all examiners were less than 50%. CONCLUSIONS Clinical experience was not associated with higher kappa coefficients or P(O) values when examiners assessed first ray position or mobility. Clinicians should acknowledge the poor reliability of first ray measurements, especially when making treatment decisions. Finally, a validity study to compare the Root techniques with a gold standard is warranted.