Jm. Hollis et al., SIMULATED LATERAL ANKLE LIGAMENTOUS INJURY - CHANGE IN ANKLE STABILITY, American journal of sports medicine, 23(6), 1995, pp. 672-677
The effect of simulated ankle ligamentous injury on ankle-subtalar joi
nt complex laxity was studied. Thirty-six intact ankles were loaded in
inversion-eversion and anterior-posterior directions. Motions of the
talus and calcaneus were measured with respect to the tibia. Ankles we
re tested at neutral, 15 degrees of dorsiflexion, and 15 degrees of pl
antar flexion. In all the specimens the anterior talofibular ligament
was sectioned and then the calcaneofibular ligament was sectioned; tes
ting was then repeated. With sectioning of the anterior talofibular li
gament, motion increased primarily in dorsiflexion with both anterior-
posterior and inversion-eversion loading. This increase was primarily
caused by a large increase in subtalar motion. Additional sectioning o
f the calcaneofibular ligament produced little change in ankle subtala
r joint motion except in dorsiflexion. Clinically, these findings show
that if an anterior-posterior drawer test shows less laxity in dorsif
lexion than in neutral and greater laxity than the contralateral asymp
tomatic side, then an isolated anterior talofibular ligamentous tear e
xists, Similarly, laxity in 15 degrees of dorsiflexion and in neutral
suggests calcaneofibular ligament disruption. During inversion-eversio
n loading, the increase in ankle-subtalar joint complex rotation with
calcaneofibular ligament sectioning occurred primarily in the ankle jo
int, implying that the calcaneofibular ligament constrains the talus t
hrough the calcaneus. Therefore, a talar tilt on stress radiographs de
monstrates a torn calcaneofibular ligament.