Chronic Ankle Instability

What chronic ankle instability is

Most ankle sprains are inversion injuries: the foot rolls inward and stretches or tears the ligaments on the outside of the ankle, mainly the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL). Many sprains heal well, but a substantial minority of people are left with ongoing instability, especially when the first sprain was not rehabilitated properly.

Instability has two components that often occur together:

• Mechanical instability: the ligaments are loose or torn, so the ankle moves further than it should.
• Functional instability: the nerves and muscles that sense ankle position and react quickly to uneven ground are impaired. This loss of position sense is called a proprioceptive deficit.

Each sprain worsens both, creating a cycle of repeated injury.

Symptoms

• the ankle repeatedly "giving way," especially on uneven ground, stepping off curbs or during sport
• recurrent ankle sprains, sometimes with little force
• a wobbly or unstable feeling
• ongoing discomfort and swelling on the outer ankle
• ankle pain or tenderness
• reduced confidence in the ankle and avoidance of activities

Deep, persistent pain, catching or locking can point to associated injuries such as a cartilage lesion of the talus.

Causes and risk factors

• previous ankle sprain, especially a severe one or several
• returning to sport too early after a sprain
• not completing balance and strengthening rehabilitation
• generalized joint hypermobility
• a high-arched foot or heel turned inward (cavovarus foot), which loads the outside of the ankle
• sports with jumping and cutting, such as basketball, volleyball and soccer

Associated injuries

Repeated sprains can cause:

• osteochondral lesions of the talus (cartilage and bone damage)
• peroneal tendon tears or dislocation
• anterior ankle impingement from scar tissue or bone spurs
• ankle arthritis over many years

Diagnosis

A doctor or physical therapist will ask about your sprain history and symptoms, then examine the ankle:

• Anterior drawer test: pulling the foot forward to check the ATFL.
• Talar tilt test: tilting the heel inward to check the CFL.
• Single-leg balance: comparing how long you can balance on each leg.
• checking peroneal tendon strength, foot shape and joint flexibility

Imaging:

• X-rays to look for fractures, bone fragments and arthritis. Stress X-rays may show excess movement.
• MRI to assess ligaments, cartilage and tendons.
• Ultrasound for ligament and tendon problems, sometimes with dynamic testing.

Treatment

Rehabilitation

A structured program for 6 to 12 weeks is the first treatment for nearly everyone and works for many people:

1. Balance training: stand on one leg, progressing to eyes closed, a pillow or balance board, and catching a ball while balancing.
2. Peroneal strengthening: resistance band exercises turning the foot outward.
3. Calf and hip strengthening: heel raises and hip abductor exercises, since hip weakness contributes.
4. Range of motion: restore ankle bend (dorsiflexion) with stretches.
5. Sport-specific drills: hopping, cutting and landing practice before full return.

Bracing and taping

A lace-up or stirrup ankle brace, or taping, reduces the risk of further sprains during sport, especially in the year after a sprain. Bracing is not a replacement for rehab.

Footwear

Supportive shoes, and lateral wedge insoles for some foot shapes.

Surgery

Surgery is considered when the ankle remains unstable despite 3 to 6 months of good rehabilitation:

• Brostrom-Gould repair: the most common operation. The stretched ligaments are shortened and reattached to the fibula, and reinforced with nearby tissue. Often done through a small incision or arthroscopically.
• Ligament reconstruction: a tendon graft is used to create new ligaments when tissue is poor quality, in heavy athletes, or after failed repair.
• Arthroscopy: a camera inspects the joint and treats cartilage damage or impingement at the same time.

After surgery, expect a boot for several weeks, then rehabilitation. Most people return to sport in about 3 to 6 months.

Outlook

Most people improve significantly with rehab and bracing. Surgery has high success rates when needed. Without treatment, repeated sprains raise the long-term risk of ankle arthritis.

Prevention after an ankle sprain

• Complete a full rehab program, even after the pain settles.
• Do not return to sport until you can hop and balance on the injured leg as well as the other.
• Use a brace for sport for at least 6 to 12 months after a sprain.
• Keep up balance exercises as part of your regular warm-up.

Frequently asked questions

Why does my ankle keep rolling?

Repeated rolling usually means previous sprains left the ligaments loose and the ankle's balance system impaired. The muscles react too slowly to correct the ankle on uneven ground. A balance and strengthening program usually helps, and surgery tightens the ligaments if it does not.

Can chronic ankle instability heal without surgery?

Often, yes. Many people regain stability with 6 to 12 weeks of targeted balance and strengthening exercises plus bracing for sport. Surgery is considered only when the ankle keeps giving way despite good rehabilitation.

What exercises help an unstable ankle?

Single-leg balance progressions, balance board work, resistance band exercises turning the foot outward, heel raises, hip strengthening and hopping drills are the core exercises. A physical therapist can tailor and progress them safely.

How long is recovery from ankle stabilization surgery?

Expect a boot and limited weight bearing for a few weeks, then several months of rehabilitation. Most people walk normally within about 6 to 8 weeks and return to sport around 3 to 6 months after surgery.