A sprained ankle is a common injury that affects people of all ages and activity levels. It happens when the ligaments that support the ankle are stretched or torn, usually due to a sudden twist or roll of the foot. Most sprains are mild and heal well with conservative intervention, but some can be severe and lead to ongoing problems, including recurrent ankle instability, if not managed properly. Early treatment and rehabilitation help most people recover and return to their usual activities.

A sprained ankle is an injury where one or more ligaments (strong bands of tissue connecting bones) in the ankle are stretched, partially torn, or completely ruptured. This usually happens when the foot turns inward (inversion), stressing the ligaments on the outside of the ankle, especially the anterior talofibular ligament (ATFL), which is the most commonly injured. Less often, the foot may turn outward (eversion), affecting the deltoid ligament on the inside of the ankle, or twist in a way that injures the ligaments between the shinbones (high ankle sprain).

Doctors classify sprains by severity:

• Grade I (mild): Ligaments are stretched with tiny tears; the ankle is stable.
• Grade II (moderate): Ligaments are partially torn; there is some instability and more swelling.
• Grade III (severe): Ligaments are completely torn; the ankle is unstable and very swollen.

Severe sprains can sometimes include bone injuries or damage to cartilage and tendons. Sprains are especially common in sports that require jumping, quick changes in direction, or running on uneven surfaces.

The most significant risk factors for a sprained ankle include a history of previous sprains, poor balance or muscle weakness, improper footwear, and participation in sports that require jumping or sudden changes in direction. The primary risk factors include:

• Previous ankle sprain: Having had a sprain before can loosen ligaments and increase the chance of another injury.
• Poor balance or proprioception: Difficulty sensing foot position (proprioception) can lead to instability and injury.
• Weak leg muscles: Weakness in the muscles around the ankle reduces support and control.
• Ligamentous laxity (loose ligaments): Naturally loose ligaments make the ankle less stable.
• High-risk sports: Activities like basketball, soccer, volleyball, tennis, and trail running often involve jumping or quick movements that stress the ankle.
• Inadequate warm-up: Not preparing muscles and joints before activity increases injury risk.
• Improper footwear: Shoes without good support, such as high heels or worn-out athletic shoes, can contribute to sprains.
• Uneven surfaces: Walking or running on rough ground, rocks, or curbs raises the risk of twisting the ankle.
• Occupational hazards: Jobs that require prolonged standing or moving on uneven ground, such as construction or mining, can increase risk.
• Body alignment issues: Abnormal foot or leg alignment may make sprains more likely.

Common symptoms of a sprained ankle include pain over the injured ligament, rapid swelling, bruising, tenderness to the touch, instability, and difficulty bearing weight. The symptoms of a sprained ankle vary depending on how severe the injury is and may include the following:

• Pain: The area over the injured ligament is usually painful, especially when moving or putting weight on the ankle.
• Swelling: The ankle often swells quickly after injury, sometimes spreading to the foot.
• Bruising: Discoloration may appear around the ankle and foot.
• Tenderness: Touching the injured area causes discomfort.
• Instability: The ankle may feel weak or as if it could "give way."
• Difficulty walking: It may be hard or impossible to put weight on the foot.
• Muscle spasms: Unintended muscle contractions can occur around the ankle.
• Reduced range of motion: Stiffness or inability to move the ankle normally.
• Popping or tearing sensation: Some people notice a "pop" at the time of injury, especially with severe sprains.

Doctors diagnose a sprained ankle by asking how the injury happened, performing a physical exam to check for tenderness and instability, and ordering imaging tests if necessary.

During the physical exam, the doctor:

• Inspects the ankle for swelling, bruising, and deformity.
• Gently presses the ligaments, bones, and tendons to find tender spots.
• Tests range of motion and strength in the ankle and foot.
• Checks for instability by moving the ankle in different directions.
• Assesses blood flow and nerve function.

If there is severe pain, inability to bear weight, or tenderness over bones, imaging tests may be needed to rule out fractures or other injuries. These tests may include:

• X-rays: Used to check for broken bones when there is bone tenderness or an inability to walk four steps.
• Stress X-rays: Taken while the ankle is pushed in different directions to check for instability.
• Magnetic resonance imaging (MRI): Used to look for ligament tears, cartilage injuries, or tendon damage.
• Ultrasound: Can show ligament injuries and joint swelling in real time.
• Computed tomography (CT): Rarely used but may help find complex fractures or cartilage injuries.

Treatment for a sprained ankle includes protection, rest, ice, compression, and elevation (sometimes collectively referred to as PRICE) to reduce pain and swelling, followed by rehabilitation to restore strength and movement. Most sprains heal with non-surgical care in six to eight weeks, but severe injuries may take longer to heal or even require surgery.

Main treatments for a sprained ankle include:

• Protection and rest: Avoid activities that cause pain. Use crutches if unable to walk normally. Severe sprains may need a short period of immobilization in a boot or cast.
• Ice and compression: Apply ice packs and wrap the ankle with an elastic bandage to limit swelling and pain, especially in the first 48 hours.
• Elevation: Keep the ankle raised above heart level to reduce swelling.
• Early controlled motion: Begin gentle range-of-motion exercises as soon as pain and swelling allow, usually within a few days. Early movement helps prevent stiffness and speeds recovery.
• Bracing and support: Use a semi-rigid brace, air stirrup, or tape to protect the ankle during healing. Mild sprains may need only a soft wrap, while moderate to severe sprains benefit from more support.
• Physical therapy and rehabilitation: A structured program helps restore strength, balance, and flexibility. Therapy progresses from gentle motion to strengthening exercises, then to balance and agility drills. Supervised therapy may help with faster recovery, but home exercise programs are also effective.
• Medications: Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naproxen, or acetaminophen, can help manage pain and swelling. Strong pain medicines are rarely needed and are used only for a short time.

Surgery is rarely required and is reserved for cases with chronic instability, high ankle sprains with separation of bones, large bone fragments, or severe injuries in elite athletes. Surgical options include ligament repair or reconstruction, and sometimes removal of loose bone or cartilage fragments. Rehabilitation after surgery is essential for good outcomes.

Potential complications of a sprained ankle include chronic instability, recurrent sprains, and osteoarthritis, which are more likely if the injury is severe or not treated properly.

The main complications include:

• Chronic instability: Ongoing feeling that the ankle "gives way" due to poor ligament healing or weak muscles.
• Recurrent sprains: Higher risk of future sprains, especially if rehabilitation is incomplete.
• Osteoarthritis: Joint degeneration may develop over time, especially after repeated injuries.
• Tendon injuries: Damage to the Achilles or peroneal tendons can occur from overuse or abnormal movement.
• Nerve damage: Injury to nerves around the ankle may cause numbness or pain.
• Ligamentous laxity: Ankle sprain can result in persistent looseness in the ligaments, which can lead to instability and may require surgery.
• Ankle fractures: Severe sprains may be accompanied by broken bones.
• Osteochondral lesions (damage to cartilage and bone): Damage to the joint surface can cause long-term pain and limited movement.
• Deep vein thrombosis (blood clots, usually in the legs): Prolonged immobility or swelling can lead to blood clots.
• Chronic swelling and pain: Ongoing discomfort and swelling may persist.
• Reduced range of motion: Stiffness or weakness can limit ankle movement.

A sprained ankle can often be prevented by wearing supportive footwear, using braces or taping during sports, and performing exercises to strengthen the ankle and improve balance. Prevention strategies include:

• Warming up before exercise or sports to prepare muscles and joints.
• Performing regular strengthening and balance exercises to improve ankle stability.
• Wearing shoes with good support that fit well and are appropriate for the activity.
• Paying attention to surfaces and avoiding uneven ground when possible.
• Using ankle braces or taping during high-risk sports or if there is a history of sprains.
• Maintaining flexibility and strength in the legs and ankles.
• Following a structured rehabilitation program after any ankle injury to prevent recurrence.

Most people with a sprained ankle recover fully with proper treatment and rehabilitation. The outcome depends on the severity of the injury, how quickly treatment begins, and whether rehabilitation is completed. Mild sprains (grade I) usually heal within one to two weeks, allowing a quick return to daily activities. Moderate sprains (grade II) may take three to six weeks, while severe sprains (grade III) often need six to twelve weeks or longer, and sometimes require surgery.

A history of previous sprains or poor rehabilitation increases the risk of chronic instability and future injuries. Up to 40% of people may have lingering symptoms such as pain, swelling, or instability. Athletes and people with high physical demands may need a longer recovery period and ongoing support, such as bracing during sports.

Long-term problems are less common but can include chronic pain, repeated sprains, and joint degeneration. Consistent rehabilitation, including balance and strength exercises, improves outcomes and lowers the risk of complications. Most people return to their usual activities, but some may need to modify sports or work if symptoms persist.

“At Yale, our approach to treating a sprained ankle is rooted in an evidence-based, patient-specific philosophy that prioritizes early functional recovery over outdated immobilization protocols,” says Yale Medicine orthopaedic surgeon Arianna Gianakos, DO. “Rather than a one-size-fits-all model, I emphasize a biomechanically informed treatment plan that considers injury severity, patient activity level, and long-term joint stability to optimize healing and reduce the risk of chronic instability—particularly in athletes and active women.”