Ankle Ligaments Injury, Tests & Assessment
The ligaments of the ankle are complex. Injury to these
ligaments are called ankle sprains. Sprain of the ankle is usually a low ankle
sprain. Occasionally, it can be a high ankle sprain. Sprain of the ankle can be
confused with other conditions that can happen around the ankle such as:
- · Osteochondral lesion
- · Peroneal tendon subluxation
- · Fracture of the lateral talar process
- · Fracture of the anterior process of the calcaneus
- · High ankle sprain (syndesmotic injury)
Here are a few tests that are used to test for injury of these ligaments:
- Anterior Drawer Test
- Squeeze Test
- External Rotation Stress Test
- Talar Tilt Test (Inversion Test)
If the patient cannot bear weight on the ankle, the patient
should get an x-ray. Injury of the deltoid ligament occurs at the medial side
of the ankle, and it is usually associated with ankle fractures. Sometimes injury
of the deltoid ligament is occult and the patient will need external rotation
stress x-rays to demonstrate injury of the deltoid ligament. Injury to the
lateral side ligaments is referred to as low ankle sprain. The anterior
talofibular ligament is the weakest ligament on the lateral side. The anterior
drawer test is done to test the competency of the anterior talofibular ligament.
It is done in 20 degrees of plantar flexion and compare it to the other side. A
shift of an absolute value of 9 mm on the lateral x-ray or 5 mm compared to the
other side is positive. The calcaneofibular ligament is usually injured after
the anterior talofibular ligament. The test used to diagnose injury of the
calcaneofibular ligament is called the talar tilt test or the inversion test. Less
than 5 degrees of tilt is usually normal. The final area of injury is called a
high ankle sprain or injury to the syndesmosis. Contrary to a low ankle sprain,
a high ankle sprain may require surgery. This is how injury to the syndesmosis
occurs. Always check the fibula proximally to avoid missing a Maisonneuve
fracture. The Maisonneuve fracture will have a proximal fibular fracture, a
syndesmotic injury, and a deltoid ligament injury. This will require surgery. The
tests used to diagnose high ankle sprains are the squeeze test and the external
rotation stress test. The squeeze test is performed by squeezing the tibia and
fibula at mid-calf. This will cause pain at the syndesmosis if a high ankle
sprain is present. The external rotation test is the other test used to
diagnose a high ankle sprain or an injury of the syndesmosis. The external
rotation test is performed by first placing the ankle into a neutral position. Then,
apply external rotation stress and finally, get a mortise view radiograph. There
is a positive result for syndesmotic injury if the tibiofibular clear space is
more than 5mm or if the medial clear space widening is more than 4mm.
