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Assessment and Treatment of Ankle Injuries
A few summers ago, while playing basketball at a YMCA camp in northern Wisconsin, I landed awkwardly and rolled my ankle. I had done this before, but this time I felt several pops. By the time I fell to the ground, my foot was displaced 70º to the medial side with a sub-talus dislocation. What does that mean? How is it different from a sprain or fracture?
Each step puts 1.5 times your body weight of pressure on your ankle. On average, we walk 1,000 miles per year. Ankle injuries account for over 14.2 million physician visits annually, but only 15% of these injuries are fractures. This article will:
- Discuss the anatomy and function of the ankle joint and foot
- Review kinematics and mechanisms of injury
- Show how to perform a thorough ankle examination
- Show how to apply appropriate treatments for an injured ankle.
Anatomy
Topographic anatomy is the language of orthopedics, using the following terms to locate a body structure relative to another structure: proximal--closer to the body's core; distal--further from the core; medial--toward the center of the body; lateral--toward the side or edge; superior--top of the foot; inferior--toward the bottom; anterior and posterior--front and back.
Understanding these terms can help us locate anatomical structures and communicate the location of injuries.
The ankle joint and foot are composed of 26 bones.1 The ankle joint starts at the distal end of the tibia and fibula. The fibula is on the lateral side of the ankle, the tibia on the medial. The distal ends of the tibia and fibula comprise the medial and lateral malleolus--or the bony prominences you can palpate. Below the malleolus are the tarsals, a group of seven bones. The talus, or ankle bone, is distal to the tibia and fibula and is the most important tarsal bone. Its odd shape is key to the ankle's range of motion and its positioning is crucial.
The calcaneus, or heel bone, is inferior and posterior to the talus. Anterior to the calcaneus are the navicular and cuboid bones. The last three tarsal bones are the cuneiform bones. Five metatarsal bones are numbered 1 through 5 medial to lateral; there are 13 phalanges in the digits of the foot.
Numerous tendons control foot and ankle movement. Tendons connect muscles to bones. Five tendons connect to the calf muscle and control movement in all directions. The Achilles tendon is the largest tendon in the ankle and connects the calcaneus bone to the calf muscle. The tendon of peroneus longus connects at the base of the fifth metatarsal and the peroneus brevis at the first. Both wrap posteriorly around the medial malleolus. The tibialis anterior connects with the cuneiform bones and runs along the anterior surface of the ankle to the calf. The hallicus longus tendon wraps on the posterior aspect of the lateral malleolus to the navicular bone.
One hundred and nine ligaments provide the integrity and strength of the ankle and foot's structure; again, five are most important. The names describe which bones the ligaments connect. The tibiofibular connects the distal ends of the tibia and fibula. The posterior talofibular ligament connects the talus and fibula. The calcaneofibular connects the calcaneus and fibula. Off of the tibia are the tibiocalcaneal and posterior tibiotalar ligaments. Tenderness or instability are indications of a ligament tear.
The location of major arteries in the ankle is important for accurately assessing circulation after an injury. Major nerves innervating the foot follow an artery. There are two arteries in the ankle that prehospital personnel must be able to locate: The dorsalis pedis artery extends from the anterior tibial artery across the top of the ankle onto the dorsum of the foot; the deep peroneal nerve lies on the lateral side of the artery.
The other artery is the posterior tibial artery. This artery runs down the posterior tibia and around the medial malleolus and is best felt on the inferior aspect of the medial malleolus.
The ankle joint is actually two joints.1,2 The proper ankle joint is formed by the tibia, fibula and talus. Immediately inferior to the ankle joint is the subtalar joint, which includes the talus and all bones that connect with it inferiorly. Alignment of these joints is crucial, as a 1 cm misalignment of the talus results in a 47% decrease in the ankle's weight-bearing ability. The two joints and five tendons of the ankle allow for four forms of movement:2 dorsiflexion--flexion of the foot upward (pulling toes toward the nose); plantar flexion--flexing the foot downward; eversion--rotating the foot outward; inversion--rotating the foot inward.
Mechanism & Types of Injury
Most ankle injuries result from hyperinversion and hypereversion of the ankle.
Like any other musculoskeletal region, the ankle can be injured by fracture, dislocation, sprain and strain. Isolated sprains and strains are common, but most fractures and dislocations also include ligament damage.
The causes of ankle injuries are numerous:
- Slips and falls on ice, stairs and rugs
- Rotational force on the athletic field
- Blunt trauma or a direct blow to the ankle joint or connecting bones
- A fall from a roof or ladder and landing feet first
- Ankle fractures are possible for passengers in a front-impact car collision.
Fractures are open, with bones puncturing the skin, or closed. Metatarsal fractures are usually from crush injuries, but can also be caused by ligaments pulling bone ends off during hyperextension.2
Physicians use a grading system for diagnosing ankle injuries.3
A grade 1 ankle sprain has no instability; minimal swelling, pain or tenderness; and, clinically, fewer than 25% torn ligament fibers. This patient will likely be able to bear weight on the injured ankle and move it through normal ranges.
Grade 2 sprains have moderate instability, pain and tenderness; swelling and ecchymosis--bruising--are apparent; and between 25%-75% of the ligament fibers are torn. This patient will have difficulty bearing a limited amount of weight on the ankle, and range of motion is impaired.
Grade 3 sprains are the most severe, with more than 75% of the ligament fibers torn. The patient will complain of severe pain and tenderness. Ankle instability is complete, and there is significant swelling and ecchymosis. This patient cannot bear any weight on the ankle and has severely impaired range of motion.
Sprains are ligament injuries; strains are tendon injuries. Both result from hyperextension, twisting, falls or excessive pulling on the ankle.
Dislocations, the separation of a joint, result from complete tearing of several ligaments, which allows for bone displacement and can be complicated with one or several fractures.2 They are caused by pulling injuries, major trauma, hyperinversion or hypereversion.
Dislocations, with or without fracture, pose a serious threat to distal circulation in the foot.
An injured ankle is not a life- threatening injury, but deformity, exposed bone ends and severe pain complaints draw our attention to the ankle and away from potential life threats.
After identifying and treating any life threats and performing a trauma exam, turn your attention to the ankle injury. Use the patient history to understand the mechanism of injury.
If the patient fell, find out the details and develop a detailed mental picture of the mechanism.
Ask your patient to point to where the ankle hurts most. Ask about pertinent medical history, including previous ankle injuries. Is this a repetitive injury, such as rolling the ankle? Try to determine if an underlying medical condition, such as a CVA or seizure, caused the injury.
Examination
Begin your physical examination by removing the patient's shoes and socks and pulling or cutting up the pant leg. Expose the lower leg from knee to toes and look at the uninjured ankle for symmetry comparison.2
Look for gross deformity that suggests a fracture or dislocation and for breaks in the skin from displaced bones.
Assess swelling. Rapid-onset swelling indicates a more serious injury; however, swelling will continue to develop for 6-24 hours.
Ask the patient to rate and describe his pain, using the OPQRST tool for pain assessment.
Check for skin color and condition at the site of most pain and deformity and distal to the injured area. Is it pale, flushed or cyanotic?
Check for temperature. Is the injured foot warmer or cooler than the uninjured foot?
Assess for a pulse at the dorsalis pedis and the posterior tibial arteries. Mark the location of both pulses with an "X" for easier reassessment. If a pulse is absent, document the time of this important pertinent negative.
To assess neurological function, first ask the patient to wiggle his toes. Next, see if he can distinguish between a sharp and soft object to assess sensation.
After assessing CSM, palpate the ankle from proximal to distal and compare to the uninjured leg as needed.
Begin palpation just below the knee, assessing the calf muscle, tibia and fibula. Some ankle injuries have associated proximal tibia fractures.
As you examine the leg, feel for crepitus, instability, minor deformities and tenderness.
When palpating, attempt to distinguish between bone and soft tissue pain. What specifically hurts?
Palpate the medial and lateral malleoli and all the tarsal bones.
Squeeze the navicular and cuboid together, then squeeze the proximal ends of the first and fifth metatarsals together. Pain at these sites could indicate a fracture from a ligament tearing off a bone end.
Check for ankle instability with the drawer test, which assesses the talofibular ligaments.3 Hold the leg just proximal to both malleoli in one hand and grasp the foot in the other. Pull the foot forward while holding the leg still. Compare the injured and uninjured leg for abnormal talus movement.
From the same starting position, invert and evert the ankle to test for instability in the tibial ligaments.
Tibiofibular ligament damage is suggested when the entire joint appears wider than the uninjured leg.
If you still have no positive findings--meaning no pain, deformity or instability--test the patient's weight-bearing ability by assisting her to a standing position and supporting her as she tries to weight the injured leg. If that is too difficult, ask the patient to press against your hand with her foot. If the patient can bear weight on the ankle, significant injury is highly unlikely.
If you have positive findings, or if the patient cannot bear weight on the foot, immobilize the ankle.3
After completing the detailed physical exam of the injured ankle, make sure you also collect a complete patient SAMPLE history and set of vital signs. Since prehospital and emergency department treatment might include pain medication, you need to have a baseline set of vitals and knowledge of the patient's current medications, health problems and medication allergies.
Treatment
The five goals for treating an injured ankle are:
- Stabilization
- Proper positioning of the ankle
- Immobilization
- Manage pain and swelling
- Transport to the hospital.
Early in your assessment, direct your partner, first responder or bystander to provide hand stabilization to the injured ankle.
Stabilize the ankle in the position found by placing your hands above and below the ankle. This minimizes ankle movement to reduce pain and prevent further injury. Stabilization may be performed before you examine the ankle.
Traditionally, EMS providers have immobilized injured joints in the position found unless distal circulation is compromised. This practice is changing because of the need to restore or protect distal circulation, sensation and movement as soon as possible.
Before applying a splint to an ankle or any long bone or joint injury, you must either realign, reposition or reduce the injury.
Realign a deformed long bone by stabilizing the bone proximal to the injury and applying gentle distal traction. Returning a long bone to proper anatomical position maximizes blood flow to and from the ankle and also reduces stress on tendons.
Joints are repositioned and moved from current location toward anatomical position to restore perfusion.
Joints are reduced to return the joint to normal anatomical position, which is the ideal immobilization position.
As long as the ankle is not dislocated and there is no open fracture, reposition the ankle to the anatomical position. If repositioning causes significant pain increase or you encounter resistance, splint in the position found and document your attempt to reposition.
If the ankle is dislocated, determine the presence or absence of distal circulation, sensation and movement.
If the patient has intact distal circulation and sensation, immobilize in the position found.
If circulation or sensation is impaired, reposition the ankle joint toward anatomical position until circulation and sensation return. Stop repositioning immediately if you meet resistance or there is a significant increase in pain.
If circulation and sensation are impaired from a dislocation, reduction is the ideal treatment. Local protocols will influence treatment of a dislocated ankle. Field reduction of a dislocation is most likely indicated in delayed care or prolonged transport contexts. For example, if it will be two or more hours until the patient is seen by an orthopedic physician, the risk of field reduction is less than the risk of tissue becoming necrotic from impaired circulation.
Reduce sooner rather than later, because reduction will decrease pain and swelling and improve circulation to the foot. There is no evidence that field reduction may cause nerve damage, but the risk of ischemia and necrosis from not reducing a dislocation is real.
If you are going to attempt reduction, consider premedication with a sedative, like Valium, and an analgesic, like Dilaudid, following local protocols.
To reduce a dislocated ankle:
- Explain to the patient the process and obtain consent.
- Place the patient supine.
- Flex the knee above the injured ankle to 90°. Flexing the knee minimizes tension on the ankle tendons and ligaments.
- Have the patient hold his leg in position with his hands.
- Encircle the ankle with both of your hands.
- Pull traction in the direction of the base of the foot, then rotate the foot back toward anatomical position.
One of two things will happen: Either the ankle will slide back into position, or you will encounter resistance and be unable to reduce.
The longer the delay in reduction, the more likely resistance will make nonsurgical reduction impossible.
Once the dislocation is reduced, or you determine you are unable to reduce the dislocation, reassess circulation and neurological function and immobilize the joint.
Although an open fracture may be particularly grotesque and painful, it is not a life-threatening injury.
Treat an open fracture as you would any other fracture. Assess distal circulation, sensation and motion, and, if necessary, reposition to attempt to restore blood flow to the distal limb.
Since most open fractures will bleed, be sure to apply well-aimed direct pressure to the sources of the bleeding. Do not force exposed bones back into the skin.
Bone ends may slide back in as you realign or reposition, but otherwise, what is out stays out. If any bones have fallen completely out of the ankle, treat them as an amputated limb following your own local protocols. Cover the opening with a sterile dressing and immobilize the limb.
Immobilization
Proper immobilization with improvised or commercial devices is essential to treating an ankle injury, as it keeps the joint in anatomical position and prohibits foot movement. Immobilizing the knee is not necessary in an isolated ankle injury.
Definitive immobilization in the hospital is with a plaster or fiberglass cast. Ideally, field immobilization provides the same support and protection.
The goal of splinting is to stabilize the injury, prevent further injury and reduce pain.
There are numerous types and sizes of splints used in prehospital care. Regardless of the type you use, the components are the same. A good splint is complete, compact and comfortable.
A comfortable splint is well-padded to provide protection from further injury and comfort to the patient.
A complete splint has structural support, is appropriately sized and fits snugly on the joint to prevent excess movement. A complete splint for a joint injury immobilizes the long bones above and below.
A compact splint has appropriate bulk. The patient needs to fit into the ambulance, and you need to be able to reassess CSM after application and during transport.
Good splints for ankle injuries are vacuum splints, formed foam and Velcro splints, and flexible aluminum SAM splints that are secured with gauze or Ace wrap. We have found that padded board splints and pillows are inadequate for splinting ankle injuries. A padded board splint allows for foot movement, and pillows provide little structural support, allow for movement and inhibit reassessment of CSM.
Reserve the use of pillow splints for severely deformed open fractures and dislocated ankles that you are unable to reposition or reduce.
After you have selected your splint of choice, measure it to the uninjured ankle to ensure proper sizing. As you apply the splint, look for voids between the splint and the foot or leg, which may require additional padding. Fill voids with loose gauze, dressings or towels to prevent excess movement and increase comfort.
Whether your splint comes with straps to secure, or you use tape or triangle bandages, the process remains the same. Apply straps distal to the body and move proximally as you secure additional straps. Do not place straps directly over the injury unless absolutely necessary.
The splint should fit snugly but not impair circulation. Once you have secured the splint, reassess CSM. Look for distal pulses, assess sharp and soft sensation, and assess for toe movement.
In adults, capillary refill is not a reliable CSM assessment. To examine for coloration, compare the injured to the uninjured foot. If CSM is impaired, readjust the splint.
Control pain and swelling by following the RICE mnemonic:
Rest by not using and splinting in a position of function.
Ice decreases pain and swelling.
Compress by immobilizing with a complete, compact and comfortable splint.
Elevation reduces blood flow to the ankle and enhances venous return, which also reduces swelling.
Administration of oxygen and verbal reassurance from a friend, family member or EMT are also powerful pain relievers.
If you are not able to give pain medications, the following are simple methods to recognize and treat pain:
- Pain medication administration can and should be done for patients with ankle and other musculoskeletal injuries, following local protocols.
- Analgesics to consider include morphine, Dilaudid, Demerol and Nubain. Nubain is an excellent non-narcotic analgesic that is very effective in orthopedic injuries.
- Consider an antiemetic like Phenergan, as many patients with fractures complain of nausea.
- Transport is indicated any time you have positive findings during your physical exam, or if the extremity was immobilized.
If the exam shows no injury and the patient is able to bear weight, ambulance transport to the emergency department is likely unnecessary. It may be best to refer the patient to his/her private physician.
The author appreciates the input and comments of Dr. Michael Collopy, a board-certified orthopedic surgeon.
References
Kevin Collopy, BA, NREMT-P, WEMT, is a paramedic crew chief for Bell Ambulance in Milwaukee, WI. He currently writes for Mosby and www.emsed.com through Emergency Preparedness Systems. He is also a lead instructor for Wilderness Medical Associates. Contact him at kcollopy@colgatealumni.org.
