Definition:
The bones of the foot and ankle are held in position by a number of ligaments and tendons. Damage to these connective tissues, caused by forcing them to stretch beyond their normal range, results in an ankle sprain. Repeated sprains can lead to chronic instability of the ankle joint with the increased likelihood of further injury.
Ligaments are strong bands of elastic connective tissue. The ankle joint has three ligaments on the lateral (outside) side of the ankle, and several on the medial (inside) side. Medial ligaments are stronger than lateral ligaments and limit the degree of inward rotation of the ankle.
Tendons attach muscles to bones. When a muscle contracts, the tendon at its end pulls on a bone and causes movement of the bone. There are several tendons that cross the ankle joint as they connect leg muscles to the bones of the ankle and foot.
Any of these structures is vulnerable to injury if subjected to sufficient force to stretch or tear them.
Ankle sprains are graded according to the severity of the injury and can involve one or more ligaments or tendons. It is also possible that a complete rupture of a ligament away from a bone can tear off a portion of bone during the initial injury.
Grade I sprains are relatively mild. Ligament fibers have been stretched but not torn and the ankle joint remains stable. Grade II sprains are considered moderate. They involve some torn ligament fibers. The ankle joint is abnormally loose when moved in certain ways. Grade III sprains are severe injuries. Grade III refers to complete tearing or rupture of the ligament. The ankle joint feels extremely unstable and may be dislocated.
Failure to properly treat a sprain, or a return to normal activity before complete healing has taken place can lead to chronic instability with an increased likelihood of repeated sprains and of developing conditions such as arthritis.
Causes:
Any situation that forces the ankle to move in a direction beyond its normal range of motion will damage the soft tissues in the ankle. It can be as simple as stepping onto a piece of uneven ground and twisting the ankle, or during sports if the ankle is abnormally rotated. Sprains can also occur on falling from a height, or during a trauma such as a motor vehicle accident.
Most sprains are caused when the ankle is twisted so that the sole of the foot faces the opposite foot and the outer ankle rolls towards the ground.
Symptoms:
Pain on initial injury. The level of pain will depend on the severity of the sprain, but may be extreme.
Rapid swelling on the outside of the ankle and foot, followed by bruising.
Possible ‘pop’ or ‘click’ sound on initial injury.
Diminished ability to bear weight on the foot, the extent depending on the severity of the injury.
Sensation of the ankle being unstable and liable to fall out of position at any time.
With chronic instability there may be a locking or clicking feeling when the ankle is moved, and a sensation of vulnerability, as though the ankle might give way at any time.
Chronic instability will cause the ankle to turn over frequently, particularly on uneven surfaces or while playing sports.
Diagnosis:
Your doctor will ask you about the circumstances of your injury and the type and severity of any symptoms you are experiencing. Your ankle and foot will be physically examined, including moving the ankle in certain ways to assess the muscle strength and laxity (looseness) of the ankle joint. The manipulation will help the doctor evaluate which ligament or ligaments have been damaged.
X-rays will be taken to look for any bone fractures as ankle fractures produce similar symptoms to those of a sprain, and it is possible for a ruptured ligament to have torn away a chip of bone. An MRI (magnetic resonance imaging) scan may be taken so that the soft tissues of the ankle and foot can be clearly viewed and the extent of the damage evaluated.
Treatment:
Initial treatment consists of rest, ice, compression, and elevation. It may be necessary for the ankle to be placed in a boot to immobilize it, and for you to use crutches temporarily to help you get around. If the injury is less severe and the ankle is able to bear some weight, a laced ankle brace for support may be sufficient. A moderate to severe sprain will require an immobilizing boot, and a sprain with a fracture will need a cast.
Ice, crushed in a bag and covered with a towel, can be applied to the ankle for as long as is comfortable, several times a day, to help reduce swelling, as will elevating the ankle above the level of your heart. You can take over the counter pain medication and non-steroidal anti-inflammatory drugs (NSAIDs) for pain relief and inflammation reduction.
All ankle sprains will need physical therapy to help with rehabilitation. Sprains take a long time to heal and it is extremely important that they heal properly before too much activity is undertaken. Failure to spend the necessary time rehabilitating the ankle may lead to the need for surgery to correct chronic instability.
The goal of surgery, though rarely required for ankle sprains, is to either tighten or reattach loose or ruptured ligaments. Although some cases can be treated arthroscopically (using narrow instruments inserted through tiny incisions) usually an open procedure is performed so that the connective tissues can be properly seen. If the ligament is unable to be repaired, sometimes a donor tendon can be fashioned into a new ligament and grafted on to the ankle.
Physical therapy may include ultrasound and electrical stimulation as well as range of motion, balance, and strengthening exercises. Chronic instability of the ankle may require prolonged wearing of a supportive ankle brace to prevent the ankle giving way.
Prevention:
Strengthening the muscles of the lower leg and ankle will provide greater stability of the joint.
Warm up properly before exercise, and wear properly fitted and appropriate shoes.
Consider using a supportive ankle brace, particularly when first resuming sporting activities, or taping your ankle securely.
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