Chronic Ankle Instability - Symptoms, Diagnosis, and Treatment

Introduction

Chronic ankle instability is when the ankle becomes frequently dislocated due to constant strain or pressure, making the ankle and adjoining ligaments weak and unstable. An ankle sprain is the most common cause of ankle instability (up to 20 percent of the overall reasons). This may occur when the ankle sprain is left untreated or improper rehabilitation is provided. Although ankle instability is common, unlike an ankle sprain, chronic ankle instability might require surgical management. The types of ankle instability can be due to mechanical or functional weakening.

How Common Is Chronic Ankle Instability?

Chronic ankle instability commonly occurs in people with weak bones or jobs requiring increased physical activity. Chronic ankle instability has an incidence of two to seven people per thousand people annually. It is most commonly seen in people involved in sports or the military, with an average incidence of 10 to 30 percent of sports injuries and around 50 to 60 per thousand people in military services.

What Causes Chronic Ankle Instability?

The cause of chronic ankle instability can be divided into two types depending on how it occurs. It can be mechanical or functional instability, where mechanical instability depends on the structure or anatomy of the bones or associated ligaments, which affect the foot or ankle mechanics. In contrast, functional instability mainly occurs due to repetitive or excessive foot usage, causing the adjoining ligaments to weaken. The reasons for both injuries are as follows:

Mechanical

• Weakening of the Ligaments: There are three ligaments associated with ankle instability, namely the anterior talofibular ligament (ATFL), the posterior talofibular ligament (PTFL), and the calcaneofibular ligament (CFL).

• The Wider Talus Bone: A disc-shaped bone at the ankle joint shows a compromised upward ankle flexion, causing ankle instability.

• Hypertrophy: of the anterior synovial joint.

• Anterior Osteophytes: Bony growths or spurs present on the body of the bone, which comprises ankle stability.

Functional

• Muscle Weakness: Occurs due to recurrent or over-functioning of the foot and ankle adjoining muscle.

• Neuromuscular Defects: These may occur in association with any syndromes or medical conditions.

• Defects in proprioception (sense of touch and feel) of the foot.

• Defects in posture and gait.

What Are the Clinical Symptoms?

The clinical symptoms are seen in patients who fail to show successful recovery from recurrent sprains. The patient gives a history of chronic ankle sprains or twisting injuries to the ankle. They offer compromised weight bearing, strenuous activity, or walking. The clinical signs seen are:

• Pain.

• Swelling.

• Inability to stand.

• Limited weight-bearing capacity.

• Twisted ankle.

How Is Chronic Ankle Instability Treated?

Ankle instability can be treated by two methods, one being conservative management and the other through surgical management.

Conservative Management:

Conservative management is the first-line treatment for managing ankle instability. The instability is managed by stabilizing it with braces and immobilization. The treatment lasts up to two months, during which treatments in the form of rehabilitation and physiotherapy may be done.

Surgical Management:

The surgical management of chronic ankle instability occurs when all the other conventional treatment modalities have failed.The surgical treatment of ankle instability focuses on three key goals. Ankle anatomy repair and anatomic and nonanatomic reconstruction. The surgical approach of repairing the anatomy of the foot shows excellent results, with a rate of 85 percent. However, this condition is not always ideal in people having loose ligaments, high arch foot deformity, weaker tissues, and long-term instability. To compensate for this, the anatomic and non-anatomic structures are reconstructed. This is done by repairing the ligaments and tendons with the help of grafts or adjacent tissues. The surgical procedure done to repair the anatomy is the Brostrom procedure and ankle arthroscopy. The recovery time taken by patients for healing is usually three to six months.

How Is Chronic Ankle Instability Diagnosed?

Chronic ankle instability can be diagnosed by:

Physical Examination: It tests the mobility of the ligament and the ankle. The test is done by palpating the foot during movements. Patients often show abnormal proprioception, peroneal nerve damage, and stretch injury.

Magnetic Resonance Imaging (MRI): It is the most preferred method for diagnosing chronic ankle instability. In the presence of injury, the MRI shows swelling, loosening, or any signs of inflammation.

Arthroscopy: It is a diagnostic procedure done to study the joints and the attaching structures using a fiber-optic camera through a minimal incision.

What Are the Associated Lesions?

Associated lesions are injuries that occur during or while managing chronic ankle instability. The lesion seen is associated with the chronic instability of the ankle and includes the following:

• Sinus Tarsi Syndrome - It is a group of conditions showing symptoms like pain and tenderness in the ankle, the heel of the foot, and the lateral aspect of the hindfoot.

• Osteochondral Defect - Localized damage to the bone and cartilage resulting from any trauma.

• Peroneal Tendinopathy - It is an injury or inflammation of the tendons resulting in pain and inability to flex the legs. Peroneal tendons are tendons that connect the lower leg to the foot.

• Subtalar Instability- It is the chronic instability of the hindfoot due to recurrent ankle instability.

What Are the Complications of Chronic Ankle Instability?

There are various other complications seen alongside chronic ankle Instability, and they are

• Delayed wound healing.

• Inflammation of the tendons.

• Stiffness of the foot.

• Recurrent instability of the ankle.

• Nerve degeneration.

• Loss of sensation in the foot.

• Chronic regional pain syndrome.

• Impingement syndrome.

• Fractures of the anterior calcaneal, fibula, and lateral talar process (these are the bones forming the foot).

Conclusion:

While ankle sprain is a commonly occurring condition that can be treated with conservative methods, chronic ankle instability must be considered seriously as it requires surgical management. Usually, ankle instability is associated with other lesions depending on the type of ankle instability. Identifying the related lesion and treating it to prevent further complications is essential. By managing chronic ankle instability by both surgical and conservative approaches alongside strenuous physiotherapy, patients show an excellent outcome with a recovery rate of almost 80 percent. Following the post-operative protocols and exercises for long-term results is also important.