Ankle sprain

BASIC INFORMATION
An ankle sprain is an injury to the ligamentous support of the ankle. Most (85%) involve the lateral ligament complex. The anterior inferior tibiofibular (AITF) ligament, deltoid ligament, and interosseous membrane may also be injured. Damage to the tibiofibular syndesmosis is sometimes called a high sprain because of pain above the ankle.
Ankle sprains are among the most common of all sports injuries. Most sprains involve the lateral ligament complex, particularly the anterior talofibular ligament. In more severe injuries, the calcaneofibular ligament may also be involved. If both of these ligaments are ruptured, the injury results in significant joint instability and is classified as a grade III (severe) sprain. (Grades I and II correspond to mild and moderate injuries, respectively.) This section reviews only the type of ankle sprain resulting from inversion (varus) injuries, which account for 85% of all sprains.

EPIDEMIOLOGY & DEMOGRAPHICS
PREVALENCE: 1 case/10,000 people each day
PREDOMINANT SEX: Varies according to age and level of physical activity

PHYSICAL FINDINGS & CLINICAL PRESENTATION
Varus sprains include a spectrum of severity, ranging from slight loss of function to injuries in which the swelling is prompt, the pain prominent, and weight-bearing impossible. A history of hearing a "pop" at the time of injury is frequently associated with the latter.
Hemorrhage resulting from torn ligaments and damaged peroneal muscle tendons may cause substantial ecchymosis. Tenderness is typically present at the site of injury, and the associated swelling may be considerable. Stability of the anterior talofibular and calcaneofibular ligaments should be assessed with the "anterior drawer" sign: With the foot held in slight plantar flexion, the examiner cups the patient's heel with one hand and the patient's shin with the other. The examiner then applies gentle anterior force in the plane of the patient's foot. Excessive anterior motion of the foot constitutes a positive test (grade III sprain). Plain radiographs exclude associated bony injury.
• Often a history of a “pop”
• Variable amounts of tenderness and hemorrhage
• Possible abnormal anterior drawer test (pulling the plantar flexed foot forward to determine if there is any abnormal increase in forward movement of the talus in the ankle mortise)
• Inversion sprains: tender laterally; syndesmotic injuries: area of tenderness is more anterior and proximal
• Evaluation of motor function
ETIOLOGY
• Lateral injuries usually result from inversion and plantar flexion injuries.
• Eversion and rotational forces may injure the deltoid or AITF ligament or the interosseous membrane.
DIAGNOSIS
DIFFERENTIAL DIAGNOSIS
• Fracture of the ankle or foot, particularly involving the distal fibular growth plate in the immature patient
• Avulsion fracture of the fifth metatarsal base
WORKUP
• History and clinical examination are usually sufficient to establish the diagnosis.
• Plain radiographs are always needed.
IMAGING STUDIES
Roentgenographic evaluation
1. Usually normal but always performed
2. Should include the fifth metatarsal base
3. All minor avulsion fractures noted
Varying opinions on the usefulness of arthrograms, tenograms, and stress films
TREATMENT
Most ankle sprains-even grade III-are treated identically. The acronym "RICE" (rest, ice, compression, elevation) applies more accurately to ankle sprains than to any other injury. Early application of a compression dressing is essential to control swelling and provide stability to the traumatized joint.

An Aircast ankle brace may be more effective than an elastic support bandage. Weight bearing should be minimal, with liberal use of crutches. Elevation of the ankle for several days hastens functional recovery by diminishing pain and swelling, and ice is also helpful (alternating 30 minutes on, 30 minutes off). The ice should be applied on top of the compression dressing and not against the skin both because close apposition of the dressing to the skin is critical to control swelling and because direct application of ice is uncomfortable and even deleterious to the skin. Referral to a physical therapist may expedite recovery. Patients should be informed that symptoms from lateral ankle sprains may take weeks or months to resolve, and that this period will be prolonged by premature attempts to bear weight on the injured ankle. Surgical repairs of ruptured lateral ligaments provide excellent outcomes but are usually necessary only in cases of chronically unstable joints.
ACUTE GENERAL Rx
Ankle sprains are often graded I, II, or III, according to severity, with Grade III injury implying complete rupture. The first line of treatment is described by the mnemonic device, RICE:
• Rest
• Ice
• Compression
• Elevation
• Varying opinions regarding the initial use of NSAIDs
• In 48 to 72 hr, active range of motion and weight bearing as tolerated
• In 4 to 5 days, exercise against resistance added
• Possible cast immobilization for some patients who require early independent walking; short leg orthoses also available for the same purpose
• Surgery is rarely recommended, even for Grade III sprains; reports of equally satisfactory outcomes with nonsurgical treatment
CHRONIC Rx
• Lateral heel and sole wedge to prevent inversion
• Protective taping or bracing during vigorous activities
• Strengthening exercises
DISPOSITION
• Lateral sprains of any severity may cause lingering symptoms for weeks and months.
1. Some syndesmotic sprains take even longer to heal.
2. Heterotopic ossification may even develop in the interosseous membrane, but long-term results do not seem to be affected by such ossification.
• Continuing lateral symptoms may require surgical reconstruction, although late traumatic arthritis or chronic instability is rare regardless of treatment.