Arthrometric measurement of ankle-complex motion: normative values.

CONTEXT Valid and reliable measurements of ankle-complex motion have been reported using the Hollis Ankle Arthrometer. No published normative data of ankle-complex motion obtained from ankle arthrometry are available for use as a reference for clinical decision making. OBJECTIVE To describe the distribution variables of ankle-complex motion in uninjured ankles and to establish normative reference values for use in research and to assist in clinical decision making. DESIGN Descriptive laboratory study. SETTING University research laboratory. PATIENTS OR OTHER PARTICIPANTS Both ankles of 50 men and 50 women (age = 21.78 ± 2.0 years [range, 19-25 years]) were tested. INTERVENTION(S) Each ankle underwent anteroposterior (AP) and inversion-eversion (I-E) loading using an ankle arthrometer. MAIN OUTCOME MEASURE(S) Recorded anterior, posterior, and total AP displacement (millimeters) at 125 N and inversion, eversion, and total I-E rotation (degrees) at 4 Nm. RESULTS Women had greater ankle-complex motion for all variables except for posterior displacement. Total AP displacement of the ankle complex was 18.79 ± 4.1 mm for women and 16.70 ± 4.8 mm for men (U = 3742.5, P < .01). Total I-E rotation of the ankle complex was 42.10 degrees ± 9.0 degrees for women and 34.13 degrees ± 10.1 degrees for men (U = 2807, P < .001). All variables were normally distributed except for anterior displacement, inversion rotation, eversion rotation, and total I-E rotation in the women's ankles and eversion rotation in the men's ankles; these variables were skewed positively. CONCLUSIONS Our study increases the available database on ankle-complex motion, and it forms the basis of norm-referenced clinical comparisons and the basis on which quantitative definitions of ankle pathologic conditions can be developed.