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Ankle Instability

 Background & Etiology (Cause)

The ankle is made of two joints. These joints need to be strong because they support the weight of the entire body. The ankle is one of the most versatile joint complexes in the body. It is built for weight bearing, mobility, adaptability and stability. The foot and ankle allow us to walk, stand, run and jump, and serves as our connection to the ground. The ankle must be able to withstand the stress of our body weight, and also be able to adapt to, and react quickly to changes in environment and walking surface.

Bones & Joints

The ankle is made up of two joints. These joints need to be strong because they support the weight of the entire body while enabling us to run, walk, and jump with precision and flexibility.

There are three bones that come together to form the ankle joint. The tibia and fibula (lower leg bones) end in prominences called the malleoli. The malleoli create the bony prominence seen on either side of the ankle, these are called the lateral malleus and medial malleolus. The ankle is made up of two joints, the inferior talocrural joint and the subtalar joint.

The inferior tibiofibular joint is located between the large bone of the lower leg (tibia) and the smaller fibula, which then attach to the talus bone of the foot to form the talocrural joint. The talocrural joint is sometimes called the true ankle joint and is responsible for dorsiflexion and plantar flexion (up and down) movement of the foot. The joint between the tibia and talus bears the most of our body weight.

Beneath the talocrural joint is the subtalar joint. The subtalar joint is located between the talus bone and calcaneus or heel bone. This joint is responsible for ankle inversion (turning in) and eversion (turning out).

Running between the tibia and fibula is a fibrous membrane called the interosseous membrane. This membrane joins the tibia and fibula all the way up the lower leg, extending toward the knee. At the upper end, near the outside of the knee, is the superior tibiofibular joint.

Any restriction or dysfunction of these joints can produce symptoms in the ankle. The bony joint surfaces all have articular cartilage that covers the ends of the bones. The articular cartilage has a smooth and shiny surface, which allows the ends of the bones to slide freely over each other.

Ligaments

The ankle joint and subtalar joint are held together by ligaments, which connect bone to bone. There are three major ligaments on the lateral (outside) aspect of the ankle. The inside (medial) aspect of the ankle has a complex of several ligaments. These structures provide stability and flexibility to the ankle.

Ankle Instability

There are different degrees of instability of the ankle. Instability is typically characterized as the feeling of the ankle joint “giving out” and is generally caused by damage to the ligaments in the ankle joint. Ankle Instability can be either lateral (along the outside) or anterior (along the front).

Lateral Ankle Instability

There are three major ligaments on the lateral (outside) aspect of the ankle; they are the anterior talofibular ligament, the posterior talofibular ligament, and the calcaneofibular ligament. Lateral Ankle Instability often occurs due to an injury or damage to one of the lateral ankle ligaments.

Anterior Ankle Instability

The anterior area of the ankle is the front, or top of the ankle. The ligaments in this area include the anterior talofibular ligament and that anterior tibiotalar ligament. These ligaments can become damaged, causing subsequent instability of the ankle.

Causes

  • Weakness of the lower leg or ankle muscles and laxity of the ankle ligaments are the most common cause of ankle instability.
  • General ligamentous laxity may predispose an individual to instability or dislocations.
  • Repetitive strain injuries (RSI) at work, or overuse activities are common in people who participate in sport activities and individuals who have jobs that require performing activities of a repetitive nature.
  • Those participating in activities characterized by repetitive motions (jumping, running, etc.) that may aggravate the ankle, resulting in ankle instability.
  • Sudden trauma or accident like a fall on the ankle

Signs and Symptoms

  • General tenderness of the ankle area
  • Discomfort with movement, especially with flexing the ankle
  • Feeling that the ankle is “dead” after repeated activity
  • A feeling that the ankle will “go out” when moving in certain positions. This is called the Apprehension Sign.
  • Significant pain of the ankle
  • Swelling, weakness, numbness and occasional bruising of the ankle area

Treatment of Ankle Instability

Conservative treatment of ankle instability is the first line of action. This includes physical therapy to reduce inflammation and associated pain. In addition, a regiment of exercises to improve muscle strength and ankle stability should be initiated. Bracing and the use of ankle supports may be indicated during rehabilitation and as a preventive measure. In more severe cases of instability involving other joint structures, surgical intervention may be necessary.

Physical Therapy Interventions for Ankle Instability

Physical Therapists are professionals, educated and trained to administer interventions. As stated in The Guide to Physical Therapist Practice interventions are the skilled and purposeful use of physical therapy methods and techniques to produce changes consistent with the diagnosis, prognosis, and the goals of the patient or client. Common interventions in the treatment of Ankle Instability include:

  • Manual Therapeutic Technique (MTT): hands on care, including soft tissue massage, and joint mobilization by a physical therapist to modulate pain and reduce any soft tissue or tendon irritation.
  • Therapeutic Exercises (TE) including strengthening exercises to improve strength of the lower leg muscles in the ankle and increase stability.
  • Neuromuscular Reeducation (NMR) to restore stability, begin retraining the lower extremity, improve joint stability and improve movement technique and mechanics (for example, jumping or running) in daily use of the involved lower extremity.
  • Modalities that can include the use of ultrasound, electrical stimulation, ice, cold laser and others to decrease pain and inflammation at the ankle and tendons.
  • Home program that includes strengthening, stretching and stabilization exercises as well as instructions to help the person perform daily tasks and advance to the next functional level.

Medical Interventions

Procedures that your physician may recommend and perform in addition to physical therapy include:

  • Initial immobilization of the instable ankle with boot or air-cast
  • REST and ICE
  • The use of NSAIDS (Non Steroidal Anti-Inflammatory Drugs)
  • Steroidal Injections to reduce inflammation
  • Pain medication to reduce the discomfort and allow the patient to perform the recommended exercises
  • Physical Therapy to include strengthening and work on balance and proprioception for ankle stability retraining
  • Surgery to correct underlying pathology and avoid instability and repeated dislocations. This may include surgical repairs or procedures to tighten the ankle ligaments.

Prognosis

Most people recover full function following a course of conservative care of physical therapy to strengthen and stabilize the ankle. Those with more involved situations such as ligament tears, or chronic dislocations will require surgery and intensive physical therapy afterward to restore full function.