- Discussion:
-
Anterior Talofibular ligament is the primary restraint in anterior drawer test;
- testing of ankle in 10 deg of plantar flexion results in greatest
amount of translation, although one cadaveric study showed that
maximum anterior excursion occurs in dorsiflexion;
- injury of the
calcaneofibular lig does not increase amount
of the anterior drawer;
- evaluates the
Anterior Talofibular ligament (look for diff. of 8 mm)
- this can be performed by securing the distal leg with one hand and
applying an anterior pull on the heel with the foot held in gentle
plantar flexion;
- Testing w/ Pt Sitting:
- when patient is sitting, knee should be flexed over edge of bench or
table and the ankle should be allowed to fall into equinus;
- examiner then stabilizes distal part of leg w/ one hand and applies
anterior force to the heel with the other hand, in attempt to
subluxate the talus anteriorly from beneath the tibia;
- be sure to allow the talus to rotate slightly medially which relaxes the
deltoid ligament (which otherwise might give a false negative test);
- Testing w/ Pt Supine:
- modified
anterior drawer test can be used when pt is supine;
- flexing the knee to about 45 deg relaxes the calf muscles;
- w/ knee hyperflexed, the ankle in equinus, & foot fixed by one of examiner's
hands to the ground or table, force is applied w/ other hand on anterior aspect
of distal part of leg, in attempt to
translate the tibia posteriorly;
- alternatively, w/ pt supine on a table w/ knees flexed about 90 deg, posterior
force is applied to the lower leg while foot is held flat on the table top;
- be sure to allow the talus to rotate slightly medially which relaxes the
deltoid ligament (which otherwise might give a false negative test);
- Radiographs:
- forward shift of more than 8 mm on a lateral radiograph is considered
diagnostic for an ATFL tear;
- distance measured between the posterior lip of the tibia & nearest part of
talus reflects anterior subluxation of the talus;
