Lateral Ankle Sprain
Edited by Kalpesh Shah, FRCS Tr Orth, M.S Orth, MRCS Ed, MBBS
A sprained ankle is one of the most common musculoskeletal injuries. It occurs when the ankle rolls inward leading to tearing of some or all of the ligaments on the outside of the ankle. Risk factors for suffering an ankle sprain include: a history of previous ankle sprains, playing high-risk sports (basketball, volleyball, soccer, etc), having a high arched foot, and overly loose ankle joint. The severity of an ankle sprain will determine the length of the recovery time. Initial treatment includes: rest, activity modification, ice, elevation, and compression. Physical therapy that focuses on range of motion and strengthening can be helpful once the initial pain and swelling has settled.
Clinical Presentation: Ankle Sprain
Patients with a sprained ankle typically describe an episode where they roll their ankle to the inside (Figure 1), which creates tearing of the ligaments on the outside aspect of the ankle (Figure 2). Patients typically have significant pain and swelling (Figure 3), and usually limp. However, quite often those who have sprained their ankle are still able to bear some weight. It is often possible for athletes who have suffered a mild or even moderate ankle sprain to be able to complete their game, albeit with considerable pain and some functional limitations This is in contrast to patients who have suffered an ankle fracture which makes weight-bearing extremely difficult, or impossible. With the ankle swollen over the outside (lateral) aspect, there is often associated redness due to the increased blood flow to this area. Bruising following an ankle sprain is common. It usually becomes apparent within 24 hours of the injury. It will tend to spread to the outside (lateral) part of the hindfoot and midfoot. Bruising can take two weeks or more to resolve.
Figure 1: Ankle Inversion, the typical mechanism of injury of an ankle sprain.
Figure 2: The Lateral Ligaments of the Ankle
Figure 3: Ankle swelling and redness after an ankle sprain
Physical Examination: Sprained Ankle
Physical examination will reveal swelling over the outer aspect of the ankle and tenderness over the outer front aspect of the ankle (Figure 4). Motion of the ankle will also be restricted due to swelling and discomfort. Unlike ankle fractures, there is usually no major tenderness over the bone on the outside of the ankle. In addition, there is typically no tenderness on the inside of the ankle (medially). It is important to assess for other areas of tenderness and potential injury, as the same mechanism that creates an ankle sprain can also lead to other injuries (ex. fracture of the anterior process of the calcaneus, talar osteochondral injury, peroneal tendon injury, foot fracture on the outside of your foot or the 5th metatarsal).
Figure 4: Main area of Tenderness
Imaging Studies: Sprained Ankle
In the emergency room, x-rays are often taken, however, they are not always indicated. In a patient with an ankle sprain, x-rays will not identify any bony abnormalities and the ankle joint will be well located. If there is no tenderness over the bone along the inside or outside of the ankle and the patient is able to take 4 steps, then according to the Ottawa ankle rules, the patient does not require x-rays.
An MRI is not indicated in the initial assessment of ankle sprains. It is generally not recommended unless symptoms persist after rehabilitation efforts have been completed -usually 8 weeks or more after the initial injury.
Ankle Sprain Classifications
Ankle sprains are typically classified as mild, moderate, and severe. It is often difficult to tell exactly which category the ankle sprain is.
- A mild ankle sprain involves partial tearing of the anterior talofibular ligament -the first ligament to be stretched when the ankle rolls inwards. In a mild ankle sprain this ligament has tearing of some of the fibers and may be even stretched, but it is intact. Mild ankle sprains will take 4-7 days to achieve most of the recovery.
- A moderate ankle sprain involves a significant tearing of the anterior talofibular ligament and some tearing of the calcaneofibular ligament. Moderate ankle sprains often take 7-14 days to mostly recover.
- A severe ankle sprain involves disruption of all of the major ligaments on the lateral aspect of the ankle, specifically the anterior talofibular ligament and the calcaneofibular (and much less commonly the posterior talofibular ligament). A severe ankle sprain is a major injury that may take 4-6 weeks, or even longer, to largely recover. Furthermore, in approximately 8-10% of patients suffering a severe ankle sprain, there will be associated injuries to the ankle joint (ex. an osteochondral injury to the talar dome) that may lead to residual symptoms.
Treatment: Sprained Ankle
The basic treatment of an ankle sprain is the R.I.C.E. approach (Rest, Ice, Compression, Elevation):
- Rest and Activity Modification: Time is usually the best treatment for a typical ankle sprain. The body just takes time to heal the injured tissue. Resting the injured ankle by limiting activity during the initial healing period is helpful.
- Ice: Applying ice to the injured ankle helps decrease swelling and improves pain control. Ice should be applied 10 minutes on and 10-15 minutes off repeatedly. Ice helps limit the blood flow to the injured ankle. Normally, increasing the blood flow to an area is a good thing. However, after an ankle sprain, excessive local blood flow leads to too much swelling during the acute phase of the injury
- Compression: Compression helps decrease the swelling. This can be achieved with a compression wrap, such as an Ace bandage.
- Elevation: Elevating the ankle (ex. placing two pillows under the leg while lying) helps to decrease swelling. Having the ankle down (ex. while standing) will tend to increase swelling and pain in the ankle.
- Anti-inflammatory medications (NSAIDs): Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) such as ibuprofen can be helpful in decreasing pain following an ankle sprain. NSAIDs lessen pain by decreasing the inflammatory response to the injury. However, there is some evidence that suggests that anti-inflammatories may have an adverse effect on ligament healing.
Patients may benefit from a short period of immobilization in a walking boot or ankle brace. In severe sprains, short periods of casting may be needed. However, in general early mobilization of the ankle is recommended and leads to a better healing and recovery.
Once the symptoms associated with the initial ankle sprain have started to improve, patients will benefit from exercises designed to improve their:
- Range of Motion (ex. Figure of Eight Exercises and Dorsiflexion Stretching)
- Strengthening: Particularly Eversion Strengthening
- Proprioception (Balance Training)
Surgery is not indicated for the treatment of acute ankle sprains. The exception would be if there were injuries to other parts of your ankle such as a displaced cartilage and bone fragment in the ankle joint due to an osteochondral injury to the talus (lower bone of the ankle joint), large tendon tears or large unstable fractures.
Patients who have recurrent ankle sprains due to ankle instability may be candidates for an ankle ligament stabilization procedure.
Edited on November 17, 2020
Previously edited by David Oji, MD, Jean Brilhault MD, and Michael Shereff, MD