Sprained ankle

Ankle sprains are common musculoskeletal injuries that occur when the ligaments of the ankle are stretched or torn due to excessive force. They can affect individuals of all ages, particularly athletes and active individuals. Proper understanding of the anatomy, causes, and risk factors is essential for effective diagnosis and management.

Anatomy of the Ankle

The ankle is a complex joint that provides stability and mobility for weight-bearing activities. It is composed of bones, ligaments, muscles, tendons, and the joint capsule, all of which work together to maintain functional movement.

Bones

• Tibia: The medial bone of the lower leg forming the medial malleolus.
• Fibula: The lateral bone forming the lateral malleolus.
• Talus: The tarsal bone that articulates with both the tibia and fibula to form the ankle joint.

Ligaments

• Lateral ligaments: Include the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and posterior talofibular ligament (PTFL), which stabilize the lateral aspect of the ankle.
• Medial ligaments: The deltoid ligament complex stabilizes the medial side of the ankle.

Muscles and Tendons

• Tendons of the peroneal muscles provide lateral stability.
• Anterior and posterior tibial tendons contribute to medial stability and movement control.
• Other muscles crossing the ankle aid in dorsiflexion, plantarflexion, inversion, and eversion.

Joint Capsule and Synovial Structures

• The joint capsule encloses the ankle, providing stability and containing synovial fluid for lubrication.
• Synovial membranes help reduce friction during movement and allow smooth articulation of the bones.

Etiology and Risk Factors

Ankle sprains typically occur due to abnormal forces applied to the joint, leading to overstretching or tearing of ligaments. Several intrinsic and extrinsic factors increase susceptibility to injury.

Common Causes

• Sports injuries, particularly those involving jumping, running, or sudden changes in direction.
• Falls on uneven surfaces or stairs.
• Twisting or rolling the ankle during daily activities.

Intrinsic Risk Factors

• Previous ankle sprains leading to ligament laxity.
• Foot morphology such as high arches or flat feet.
• Poor proprioception or neuromuscular control.

Extrinsic Risk Factors

• Improper footwear that does not provide adequate support.
• Uneven or slippery surfaces.
• Fatigue during physical activity reducing protective reflexes.

Classification and Grading

Ankle sprains are classified based on the severity of ligament injury and the degree of functional impairment. Accurate grading is essential for guiding treatment and predicting recovery time.

Grades of Sprain

• Grade I: Mild stretching of ligaments with microscopic tears. Minimal swelling and tenderness are present. Full weight-bearing is usually possible.
• Grade II: Partial tearing of ligaments. Moderate swelling, bruising, and pain occur. Weight-bearing may be painful and limited.
• Grade III: Complete rupture of one or more ligaments. Severe swelling, bruising, and instability are noted. Weight-bearing is typically not possible without assistance.

Mechanism of Injury

• Inversion Sprains: Most common type, occurring when the foot rolls inward, stressing the lateral ligaments.
• Eversion Sprains: Less common, occur when the foot rolls outward, affecting the medial ligaments.
• High Ankle Sprains: Involve injury to the syndesmotic ligaments between the tibia and fibula, usually from rotational forces.

Clinical Features

The clinical presentation of an ankle sprain varies with severity and type of injury. Prompt recognition of signs and symptoms facilitates early management and reduces complications.

Symptoms

• Pain at the site of ligament injury, which may worsen with movement or weight-bearing.
• Swelling around the ankle joint, sometimes extending to the foot.
• Bruising or discoloration appearing within hours to days after injury.
• Feeling of instability or weakness in the ankle.

Signs on Physical Examination

• Tenderness localized over the injured ligaments.
• Limited range of motion due to pain and swelling.
• Visible deformity in severe cases.
• Palpable gap in complete ligament rupture (Grade III).

Special Tests

• Anterior Drawer Test: Assesses integrity of the anterior talofibular ligament.
• Talar Tilt Test: Evaluates the calcaneofibular ligament and overall lateral stability.
• External Rotation Test: Used to identify high ankle sprain involving syndesmotic ligaments.

Diagnostic Evaluation

Diagnosis of an ankle sprain is primarily clinical, based on history and physical examination. Imaging is used selectively to confirm the extent of injury or rule out associated fractures and other pathologies.

History and Clinical Examination

• Mechanism of injury, including direction of ankle twist and force involved.
• Onset, location, and severity of pain.
• Previous ankle injuries and functional limitations.
• Assessment of weight-bearing ability and gait.

Imaging Studies

• X-ray: Used to rule out fractures, avulsion injuries, or dislocations.
• MRI: Provides detailed visualization of ligaments, tendons, and soft tissue structures; indicated in severe or complex sprains.
• Ultrasound: Can detect ligament tears and guide early rehabilitation in selected cases.

Indications for Imaging

• Severe pain with inability to bear weight.
• Suspected fracture based on physical findings or Ottawa ankle rules.
• Persistent instability or pain despite conservative management.

Management

Management of ankle sprains depends on severity and includes conservative measures, rehabilitation, and in selected cases, surgical intervention.

Conservative Treatment

• RICE Protocol: Rest, Ice, Compression, and Elevation to reduce pain and swelling.
• Immobilization using ankle braces, splints, or elastic bandages.
• Physical therapy focusing on range of motion, strengthening, and proprioception exercises.
• Pain management with non-steroidal anti-inflammatory drugs (NSAIDs) or acetaminophen as needed.

Surgical Management

• Indications: Complete ligament rupture, chronic instability, or failure of conservative therapy.
• Techniques include ligament repair, reconstruction, or tendon augmentation.
• Post-operative rehabilitation emphasizes gradual weight-bearing, mobility, and strength recovery.

Complications

While most ankle sprains heal with appropriate care, complications can occur, especially in severe or recurrent injuries. Early recognition and management are important to prevent long-term functional deficits.

• Chronic Ankle Instability: Persistent ligament laxity leading to recurrent sprains and a feeling of giving way.
• Recurrent Sprains: Increased risk due to inadequate rehabilitation or pre-existing ligament weakness.
• Post-Traumatic Arthritis: Degenerative changes in the joint following repeated injuries or severe ligament damage.
• Associated Injuries: Tendon ruptures, cartilage damage, or fractures that may accompany severe sprains.

Prevention

Preventive strategies focus on reducing the risk of initial injury and recurrence through training, equipment, and proper rehabilitation.

• Strengthening Exercises: Targeting the muscles around the ankle to improve support and stability.
• Proprioception Training: Balance and coordination exercises to enhance neuromuscular control.
• Proper Footwear: Supportive shoes suitable for the activity to reduce risk of ankle rolling.
• Ankle Supports: Braces or taping during high-risk activities, particularly in athletes with prior sprains.
• Training Modifications: Gradual increase in activity intensity and avoidance of uneven or slippery surfaces.

Prognosis

The outcome of an ankle sprain depends on the severity of ligament injury, quality of treatment, and adherence to rehabilitation protocols. Most mild sprains resolve completely, while severe injuries may require extended recovery and careful monitoring.

• Recovery Timeline: Grade I sprains usually recover within 1 to 3 weeks. Grade II sprains may take 3 to 6 weeks, and Grade III sprains often require 6 to 12 weeks or longer.
• Factors Affecting Prognosis: Age, prior ankle injuries, comorbidities, and compliance with therapy influence recovery speed and functional outcomes.
• Return-to-Sport Criteria: Pain-free full range of motion, adequate strength, stability, and successful completion of functional tests are essential before resuming sports activities.

References

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