Ligament fibre recruitment and forces for the anterior drawer test at the human ankle joint  F. Corazza, J.J. O’Connor, A. Leardini, V. Parenti Castelli  Journal of Biomechanics  Volume 36, Issue 3, Pages 363-372 (March 2003) DOI: 10.1016/S0021-9290(02)00425-6

Fig. 1 Kinematics of the ankle joint in passive flexion as guided by the four-bar linkage ABCD. The thicker segments represent the isometric fibres of the CaFi (AB) and TiCa (CD) ligaments (only five fibres are here represented). The position of the instantaneous centre of rotation (IC) of the linkage is depicted as an empty circle. The dash–dot arrow represents instantaneous position and direction of the contact force. Significant changes in shape and direction for all the ligaments can be appreciated. The reference coordinate system is also reported. Journal of Biomechanics 2003 36, 363-372DOI: (10.1016/S0021-9290(02)00425-6)

Fig. 2 Antero-medial (left) and antero-lateral (right) views of the three-dimensional model of a left ankle complex. Articular surfaces for the tibial mortise and trochlea tali (cylindrical meshes), ligaments (only five fibres are included for clarity), and the reference coordinate system are shown together with the mid-sagittal silhouette of the bones from the 4BL model. The y-axis coincides with the long axis of the tibia. Journal of Biomechanics 2003 36, 363-372DOI: (10.1016/S0021-9290(02)00425-6)

Fig. 3 Diagrammatic representation of the modelled ligaments when projected in the sagittal plane. The lower part of the ligament (3 fibres) is taut, whereas the upper part (7 fibres) is slack. The dashed line represents the principal axis of the first taut fibre. PQ and RS represent respectively ligament origin and insertion segments. Axis ξ is parallel to x. θ represents the angle between the horizontal direction ξ and the sagittal projection of fibre principal axis. φ represents the angle between the horizontal ξ and the sagittal projection of ligament insertion segment RS. Journal of Biomechanics 2003 36, 363-372DOI: (10.1016/S0021-9290(02)00425-6)

Fig. 4 Stress/strain curves from the modelled ligaments, with mechanical characteristics taken from the literature: estimated for three ligaments in data set Ω (Attarian et al., 1985), directly taken for five ligaments in data set Ψ (Siegler et al., 1988). Journal of Biomechanics 2003 36, 363-372DOI: (10.1016/S0021-9290(02)00425-6)

Fig. 5 Percentage of taut fibres within each ligament, throughout the passive flexion range. The higher the J, the more fibres are close to the “just tight” condition. When J=100%, all fibres are just tight. Journal of Biomechanics 2003 36, 363-372DOI: (10.1016/S0021-9290(02)00425-6)

Fig. 6 Diagrammatic representation in the sagittal plane of ligament fibre recruitment at the ankle joint in response to ADT force. Four positions, 2mm step, are reported, starting from the neutral position. Journal of Biomechanics 2003 36, 363-372DOI: (10.1016/S0021-9290(02)00425-6)

Fig. 7 Load/displacement plots for five flexion angles (20° Pl, 10° Pl, Neutral position, 10° Do, 20° Do), from both data set Ω and Ψ. Mean results from experimental studies in the literature are also reported: empty circles from Bulucu et al. (1991), and asteriscs from Bahr et al. (1997). Journal of Biomechanics 2003 36, 363-372DOI: (10.1016/S0021-9290(02)00425-6)

Fig. 8 Displacement versus flexion angle for different values of the external load, for both Ω and Ψ data sets. Journal of Biomechanics 2003 36, 363-372DOI: (10.1016/S0021-9290(02)00425-6)