Medial Ankle Sprain

Deltoid Ligament Ankle Sprain

Summary

A medial ankle sprain is a relatively uncommon, but serious injury that affects the inside of the ankle. This is contrasted with the common classic ankle sprain which affects the outside of the ankle. A medial ankle sprain occurs from a major acute injury that results in the strong deltoid ligament on the inside of the ankle being partial or completely torn. Patients will have notable pain and will often be unable to bear weight. If the deltoid ligament is only partially torn and the ankle joint is stable this injury can be treated without surgery in a cast or boot, although a full recovery can take many months. Complete tearing of the deltoid ligament is often associated with a fracture of the bone on the outside of the ankle (the fibula) creating an unstable ankle fracture which will require surgery.

How does a Medial Ankle Sprain Occur?

A medial ankle sprain is a relatively uncommon, but potentially very serious ankle injury. This injury occurs when a twisting or loading injury to the ankle causes an excessive force on the structures on the inside of the ankle. Typically, the injury occurs when the foot is in an everted position. This is the opposite mechanism to a classic ankle sprain. A medial sprain of the ankle results in tearing of the strong deltoid ligament on the inside of the ankle joint. The tearing is usually partial as complete tearing is often associated with an unstable ankle fracture.

Patient suffering a medial sprain of the ankle will have immediate pain and swelling on the inside fo the ankle. Putting weight on the injured ankle may be difficult or even impossible for more severe injuries. Other injuries such as a talar osteochondral injuries or an associated fibular fracture can also occur.

What are the Symptoms of a Deltoid Ligament Ankle Sprain (Medial Ankle Sprain)

Patients suffering a medial ankle sprain will have pain and swelling on the inside of their ankle. They will walk with a limp or be unable to weight-bear. Stressing the structures on the inside of the ankle will create discomfort. The ankle range of motion may be limited. There may also be pain in other areas around the ankle if there are associated injuries.

Imaging Study Findings in a Medial Ankle Sprain

An isolated sprain of the medial ankle with partial tearing of the deltoid ligament may have normal x-rays. However, if there is extensive tearing of the deltoid ligament the inside of the ankle joint may gap open if stressed. If there is an associated fracture of the fibula this will be seen on x-ray.

In patients with a medial ankle sprain an MRI will usually demonstrate tearing of the deltoid ligament. It may also show considerable fluid (blood-edema) around the injured deltoid ligament. Other injuries may also be identified.

Treatment of a Medial Ankle Sprain

Medial ankle sprains with a partially torn but stable deltoid ligament can be treated conservatively. A period of protection of 2–6 weeks in a boot or cast may be needed. Once the swelling settles physical therapy working on range of motion, strengthening, and balance (proprioception) should be performed until strength and function has returned to normal. This can take a number of months depending on the severity of the injury.

Surgical Treatment of Deltoid Ligament Injuries

A medial deltoid ligament injury with resulting gross instability of the ankle is often associated with a fibular fracture. This injury is a type of unstable ankle fracture and usually requires surgery. The surgery would include reducing and fixing the fibula fracture. Also, if there is gross instability and gapping from an extensive medial deltoid ligament injury a surgical repair of this ligament injury may be beneficial. Fortunately, most isolated medial ankle sprains still have a stable deltoid ligament with only partial tearing and will not require surgery.

Edited January 19, 2024