Ankle and Foot Clinic of Idaho

Call Us:  (208) 529-0229

This is manifested as chronic pain and/or chronic instability.  Many people use the term “weak ankles” to describe their instability or the reason they continue to sprain their ankles.  There are two types of instability:

​Ankle sprains are one of the most common injuries in sports and are among the most frequently treated injuries in the Emergency

Department.  The most common type of sprain is the lateral ankle sprain where the foot twists under the leg (inversion).  When this occurs, the ligaments are strained or even ruptured. A minor sprain will strain the ligaments and usually cause a little swelling, but when the ligaments rupture, there is typically severe swelling, pain, and bruising.  When this occurs, a fracture needs to be ruled out.  There are areas in the ankle and foot where the fracture is difficult to identify and therefore a series of high ankle and foot x-rays should be performed.  

Ankle sprains are graded according to the extent of the injury:


Ankle sprain


Grade III injuries should always have x-rays to rule out fracture.  Splinting or immobilization is often initially required due to pain and difficulty in ambulation.  These injuries should be braced as soon as tolerated to allow for active rehabilitation.  In the past, these injuries were often casted for extended periods of time, which led to stiff joints and prolonged recovery. If appropriately managed most of these heal without residual complications.

Even with complete rupture of the ligaments, surgical treatment is never performed in acute cases. Studies show that early surgical treatment may lead to more complications in the future.  Surgical treatment is reserved for chronically painful or unstable ankles.

If surgery is necessary, this can be performed through minimally invasive ankle arthroscopy and minimal incision stabilization.  Some require more extensive procedures.

1. Functional instability is where the ligaments have healed appropriately, but there is still a problem with feelings of weakness or problems with recurrent sprains. This is usually due to pain elicited when the ankle is in a certain position (causes of pain are discussed below).  These circumstances in a healthy ankle would cause the muscles to contract and stabilize the joint; however, the pain causes the muscles to actually give as a mechanism to prevent or eliminate the painful position.  The ankle therefore relaxes and a sprain results

2. Anatomic instability is where the ligaments have healed inappropriately.  They may be abnormally lengthened or completely ruptured. In this case, there is no structural stability of the ankle increasing the risk of subsequent sprains.
Prognosis for full recovery is usually excellent in grade I and II.  Grade III prognosis is usually very good with some studies showing full recovery up to 80% of the time.  The other 20% will continue to have problems associated with the injury. 

  • Grade I: A pulling of the ligament, with almost no residual complication.  There is typically a little swelling, but no bruising.
  • Grade II: An attenuation or partial tear of the ligaments, which leads to more swelling and possibly some local bruising.
  • Grade III: A complete rupture of the ligaments with severe bruising and swelling. A fracture needs to be ruled out.