Ankle Instability Surgery

Ankle instability surgery is performed to treat an unstable ankle and involves the repair, or replacement of a torn or stretched ligament.

There are two types of ankle instability surgeries:

• Anatomic repair: This surgery involves shortening and tightening of the stretched ligament
• Non-anatomic repair: This surgery uses a tendon as a graft to replace the damaged ligament.

Disease overview

Ankle instability is a chronic condition characterised by the recurrent slipping of the outer side of the ankle. Instability is generally noticed during movement of the ankle joint but can also occur while standing.

The symptoms of ankle instability include:

• The ankle feels unstable.
• The ankle turns repeatedly while walking on uneven surfaces or during a sporting activity.
• Pain, tenderness and swelling is present in the ankle joint.

Ankle instability usually results from repeated ankle sprains. Inadequate healing of a sprained ligament or incomplete rehabilitation of the affected ligament can result in instability. Recurrent injury to the ligaments further weakens them and aggravates the instability, which predisposes to the development of additional ankle problems.

Indications

Surgery is recommended in patients with a high degree of ankle instability and in those who have failed to respond to nonsurgical treatments.

• Anatomic repair is preferred in most cases of ankle instability.
• Non-anatomic repair is performed in obese patients requiring increased stability or when tightening of the stretched and scarred ligaments is not strong enough, and needs to be reinforced with a tendon graft.

Surgical procedure

Ankle instability surgery involves the repair or reconstruction of the injured ankle ligaments. Ankle instability surgeries can be categorised into either anatomic repair or non-anatomic repair, also called reconstructive tenodesis.

Anatomic repair 

This involves the reconstruction of the stretched or torn ligaments. The surgery is performed under epidural anaesthesia. Your surgeon makes an incision on the ankle to expose the damaged joint and ligaments. The joint capsule and ligaments are examined, and the edges of the torn ligament are shortened and repaired with sutures. The ends may be overlapped and then sutured to strengthen the ligament. Your surgeon then covers the repaired ligament with the extensor retinaculum, a dense band of connective tissue, to reinforce the ligament further. The range-of-motion is evaluated; the incision is closed and a sterile bandage is applied.

Reconstructive tenodesis 

This is a tendon transfer procedure that uses your own tendon or a cadaver tendon as a graft to replace the damaged tendon. The surgery is performed under epidural anaesthesia. Your surgeon makes an incision on your ankle. Drill holes are created where the damaged ligament normally attaches to the lower end of the fibula (calf bone) on one side and the talus (ankle bone) on the other end. Your surgeon then harvests the peroneus brevis muscle tendon, found on the outer edge of the small toe, and weaves it through the drill holes, to form a ligament complex. Range-of-motion is evaluated. The incision is closed and a sterile bandage is applied.

Postoperative Care

After surgery, your foot will be immobilised with a cast or splint. You will be provided crutches to avoid bearing weight on the operated ankle. Your doctor will remove the splint and provide a removable boot to be worn for 2 to 4 weeks. Physiotherapy will be initiated to strengthen your joint and improve range-of-motion. Complete recovery may take 10 to 12 weeks.

Advantages and disadvantages

The advantages of the anatomic repair include:

• Simple surgical procedure that makes use of your own anatomy to repair the damage
• Preserves complete joint mobility
• Rapid recovery
• Smaller incision
• Fewer complications

The disadvantage of the anatomic repair include:

• Loosening of the ligaments, requiring additional repairs

The advantages of the nonanatomic repair include:

• Provides increased strength
• Can be used when host tissues are severely damaged
• Provides additional stability in obese patients

The disadvantages of the nonanatomic repair procedures include:

• Decreased rear foot motion
• Does not preserve the peroneus brevis, an important structure for the ankle’s dynamic stability

Risks and complications

As with all surgical procedures, ankle instability surgery may be associated with certain complications including:

• Injury to the superficial nerves
• Chronic pain
• Stiffness
• Need for second surgery (rare)