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KembaraXtra-Medicine- Ankle Sprain
Basic Information and Definition
An ankle sprain is an injury involving the ligamentous structures that stabilize the ankle joint. Approximately 85% of ankle sprains affect the lateral ligament complex, most commonly the anterior talofibular ligament (ATFL), followed by the calcaneofibular ligament (CFL). Medial ankle sprains involve the deltoid ligament and are less common but tend to be more severe. High ankle sprains involve injury to the distal tibiofibular syndesmosis, including the anterior inferior tibiofibular ligament, posterior inferior tibiofibular ligament, interosseous membrane, and inferior transverse ligament. Ankle sprains are typically graded as I, II, or III based on the extent of ligament injury and joint stability.
Classification
Grade I sprains involve stretching of the ATFL with mild swelling, tenderness, and no joint instability, and patients are usually able to bear weight. Grade II sprains consist of a tear of the ATFL with a sprain of the CFL, resulting in moderate swelling, tenderness, and mild to moderate instability, often demonstrated by a positive anterior drawer test. Grade III sprains involve complete tears of both the ATFL and CFL, producing severe swelling, marked instability on anterior drawer and talar tilt testing, and inability to bear weight. These injuries may require prolonged immobilization and, in some cases, surgical intervention.
ICD-10-CM Codes
Coding includes sprains of the calcaneofibular ligament, deltoid ligament, or tibiofibular ligament, with specification of laterality, encounter type (initial, subsequent, or sequela), and whether the ankle is right, left, or unspecified.
Epidemiology and Demographics
Ankle sprains are among the most common musculoskeletal injuries, with an estimated prevalence of one case per 10,000 people per day. They are especially common in athletic and physically active populations. There is no clear gender predominance, and incidence varies with age and activity level.
Physical Findings and Clinical Presentation
Patients often report a twisting injury with inversion or eversion and may describe hearing or feeling a “pop” at the time of injury. Examination typically reveals swelling, ecchymosis, and tenderness over the affected ligaments and malleoli. Lateral ankle sprains usually present with pain over the ATFL and CFL, whereas medial sprains cause tenderness over the deltoid ligament. Weight-bearing ability varies with injury severity.
Provocative Testing
The anterior drawer test assesses the integrity of the ATFL by evaluating anterior translation of the talus relative to the tibia. The talar tilt (inversion stress) test evaluates lateral ligament stability, particularly the CFL. Syndesmotic injury is assessed with the squeeze test, in which compression of the tibia and fibula at the mid-calf produces distal ankle pain.
Etiology and Risk Factors
Inversion combined with plantarflexion is the most common mechanism for lateral ankle sprains. Eversion and rotational forces may injure the deltoid ligament or syndesmosis. Risk factors include poor balance, impaired proprioception, and weakness of the peroneal muscles.
Diagnosis
Diagnosis is primarily clinical, based on history and physical examination. Most ankle sprains can be diagnosed without advanced testing, provided fracture and significant instability are excluded.
Differential Diagnosis
The differential includes ankle and foot fractures (including malleolar, talar dome, calcaneal, and fifth metatarsal fractures), Lisfranc injury, Achilles tendon rupture, and peroneal tendon rupture.
Workup and Imaging
Plain radiographs are not routinely required unless fracture is suspected. The Ottawa ankle rules guide imaging decisions and recommend radiographs when there is malleolar or midfoot pain with bony tenderness or inability to bear weight. When indicated, initial imaging includes weight-bearing anteroposterior, lateral, and mortise views. Stress radiographs may be used to assess instability. MRI is reserved for patients with persistent symptoms despite adequate conservative management and may reveal ligament tears, tendon injury, or osteochondral lesions.
Acute Treatment
Initial management follows the PRICE principle: protection with a brace or boot, rest, ice for the first 3 to 7 days, compression, and elevation. Pain control is achieved with NSAIDs or acetaminophen. After the first 48 hours, early controlled motion using a functional ankle brace is encouraged. Short-term immobilization, up to 10 days, may shorten recovery in more severe sprains. Physical therapy is recommended to restore range of motion, improve proprioception, and strengthen supporting musculature. Grade III sprains and syndesmotic injuries with significant instability should be referred for orthopedic evaluation, as surgical management may be required in selected patients.
Chronic Management and Rehabilitation
Rehabilitation focuses on strengthening, balance training, and prevention of reinjury. Lateral heel wedges may reduce hindfoot inversion. Protective taping or bracing is recommended during high-risk activities and should be continued for up to 6 months in patients with grade II or III sprains.
Disposition and Prognosis
Most ankle sprains resolve within 2 to 6 weeks, although residual pain, swelling, or stiffness may persist for months. Syndesmotic injuries typically require longer recovery. Chronic instability is uncommon but may occur in a minority of patients despite appropriate rehabilitation.
Referral
Orthopedic referral is indicated for patients who fail to improve with conservative treatment, those with suspected high ankle sprains, or patients with persistent instability or pain beyond 6 to 8 weeks.
Pearls and Considerations
Delayed recovery should prompt evaluation for occult fractures, talar dome lesions, chronic tendinopathy, peroneal tendon pathology, reflex sympathetic dystrophy, or syndesmotic injury. Repeat imaging, including MRI, may be necessary in refractory cases.
Related Content
Ankle Sprain (Patient Information) and Ankle Fracture (Related Key Topic).
Basic Information and Definition
An ankle sprain is an injury involving the ligamentous structures that stabilize the ankle joint. Approximately 85% of ankle sprains affect the lateral ligament complex, most commonly the anterior talofibular ligament (ATFL), followed by the calcaneofibular ligament (CFL). Medial ankle sprains involve the deltoid ligament and are less common but tend to be more severe. High ankle sprains involve injury to the distal tibiofibular syndesmosis, including the anterior inferior tibiofibular ligament, posterior inferior tibiofibular ligament, interosseous membrane, and inferior transverse ligament. Ankle sprains are typically graded as I, II, or III based on the extent of ligament injury and joint stability.
Classification
Grade I sprains involve stretching of the ATFL with mild swelling, tenderness, and no joint instability, and patients are usually able to bear weight. Grade II sprains consist of a tear of the ATFL with a sprain of the CFL, resulting in moderate swelling, tenderness, and mild to moderate instability, often demonstrated by a positive anterior drawer test. Grade III sprains involve complete tears of both the ATFL and CFL, producing severe swelling, marked instability on anterior drawer and talar tilt testing, and inability to bear weight. These injuries may require prolonged immobilization and, in some cases, surgical intervention.
ICD-10-CM Codes
Coding includes sprains of the calcaneofibular ligament, deltoid ligament, or tibiofibular ligament, with specification of laterality, encounter type (initial, subsequent, or sequela), and whether the ankle is right, left, or unspecified.
Epidemiology and Demographics
Ankle sprains are among the most common musculoskeletal injuries, with an estimated prevalence of one case per 10,000 people per day. They are especially common in athletic and physically active populations. There is no clear gender predominance, and incidence varies with age and activity level.
Physical Findings and Clinical Presentation
Patients often report a twisting injury with inversion or eversion and may describe hearing or feeling a “pop” at the time of injury. Examination typically reveals swelling, ecchymosis, and tenderness over the affected ligaments and malleoli. Lateral ankle sprains usually present with pain over the ATFL and CFL, whereas medial sprains cause tenderness over the deltoid ligament. Weight-bearing ability varies with injury severity.
Provocative Testing
The anterior drawer test assesses the integrity of the ATFL by evaluating anterior translation of the talus relative to the tibia. The talar tilt (inversion stress) test evaluates lateral ligament stability, particularly the CFL. Syndesmotic injury is assessed with the squeeze test, in which compression of the tibia and fibula at the mid-calf produces distal ankle pain.
Etiology and Risk Factors
Inversion combined with plantarflexion is the most common mechanism for lateral ankle sprains. Eversion and rotational forces may injure the deltoid ligament or syndesmosis. Risk factors include poor balance, impaired proprioception, and weakness of the peroneal muscles.
Diagnosis
Diagnosis is primarily clinical, based on history and physical examination. Most ankle sprains can be diagnosed without advanced testing, provided fracture and significant instability are excluded.
Differential Diagnosis
The differential includes ankle and foot fractures (including malleolar, talar dome, calcaneal, and fifth metatarsal fractures), Lisfranc injury, Achilles tendon rupture, and peroneal tendon rupture.
Workup and Imaging
Plain radiographs are not routinely required unless fracture is suspected. The Ottawa ankle rules guide imaging decisions and recommend radiographs when there is malleolar or midfoot pain with bony tenderness or inability to bear weight. When indicated, initial imaging includes weight-bearing anteroposterior, lateral, and mortise views. Stress radiographs may be used to assess instability. MRI is reserved for patients with persistent symptoms despite adequate conservative management and may reveal ligament tears, tendon injury, or osteochondral lesions.
Acute Treatment
Initial management follows the PRICE principle: protection with a brace or boot, rest, ice for the first 3 to 7 days, compression, and elevation. Pain control is achieved with NSAIDs or acetaminophen. After the first 48 hours, early controlled motion using a functional ankle brace is encouraged. Short-term immobilization, up to 10 days, may shorten recovery in more severe sprains. Physical therapy is recommended to restore range of motion, improve proprioception, and strengthen supporting musculature. Grade III sprains and syndesmotic injuries with significant instability should be referred for orthopedic evaluation, as surgical management may be required in selected patients.
Chronic Management and Rehabilitation
Rehabilitation focuses on strengthening, balance training, and prevention of reinjury. Lateral heel wedges may reduce hindfoot inversion. Protective taping or bracing is recommended during high-risk activities and should be continued for up to 6 months in patients with grade II or III sprains.
Disposition and Prognosis
Most ankle sprains resolve within 2 to 6 weeks, although residual pain, swelling, or stiffness may persist for months. Syndesmotic injuries typically require longer recovery. Chronic instability is uncommon but may occur in a minority of patients despite appropriate rehabilitation.
Referral
Orthopedic referral is indicated for patients who fail to improve with conservative treatment, those with suspected high ankle sprains, or patients with persistent instability or pain beyond 6 to 8 weeks.
Pearls and Considerations
Delayed recovery should prompt evaluation for occult fractures, talar dome lesions, chronic tendinopathy, peroneal tendon pathology, reflex sympathetic dystrophy, or syndesmotic injury. Repeat imaging, including MRI, may be necessary in refractory cases.
Related Content
Ankle Sprain (Patient Information) and Ankle Fracture (Related Key Topic).
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