Estimation of ankle joint parameters in typically developed adults using functional calibration methods.

<bold>Background: </bold>Despite of many attempts to determine or correct hip and knee joint parameters via non-invasive techniques such as regression or functional methods, in conventional gait models the position of the ankle joint center still is assumed at the center point between malleoli.<bold>Research Question: </bold>The aim of this study was to estimate the ankle joint parameters using a functional approach.<bold>Methods: </bold>To this aim, we used data of 23 typically developed adults performing two different calibration motions. Subsequently, we applied functional approaches to determine the functional joint center and axis.<bold>Results: </bold>The results show significant differences for ankle joint parameters in all directions for both calibration motions applied with respect to the malleoli line. Most prominently, we find a shift of the ankle joint center of 7 % of the foot length anteriorly to the malleoli mid-point when applying functional calibration.<bold>Conclusion: </bold>These significant alterations of the ankle joint center and axis indicate the importance of accurate determination of ankle joint parameters and consequently their influence on the clinical outcome. [ABSTRACT FROM AUTHOR]