Sprained vs Broken Ankle

Introduction

Ankle injuries are some of the most common injuries to occur, the most common are ankle sprains and ankle fractures. When an incident occurs, and the ankle experiences physical trauma, most people are unsure whether the ankle is sprained or broken. It is important to know the difference, whilst both may present with similar signs and symptoms, treatment goals and methods are different.

Ankle anatomy

The anatomical structure of the ankle is made up of two large joints: the true ankle joint and the subtalar joint. The true ankle hinge joint moves the ankle up and down, consisting of the 3 bones; the tibia, the fibula proximally, and the talus distally. The tibia, also known as the shin bone, runs the length of the inside of the ankle. The fibula is the leg bone located next to the tibia and runs the length of the outside of the ankle. The talus is the small bone underneath the tibia and fibula. These bones are surrounded by ligaments to support the joint, this includes the deltoid, lateral and syndesmotic ligaments. Ligaments are dense, fibrous connective tissue between muscle and bone, or bone and bone. Their function is to transmit mechanical energy and stabilise the skeleton for movement.^1,2,3  

Sprained ankle

A sprained ankle is defined as an injury to the ligaments in the ankle, with the severity of sprain ranging from grade I to III injuries. Sprains are typically caused by rolling or twisting of the ankle. Grade I ankle sprain involves a partial tear of the ligament; symptoms include, mild tenderness and swelling, little functional loss, no mechanical instability, and moderate pain and swelling. Grade II ankle sprain involves an incomplete tear of ligaments; symptoms include some loss of motion and function, moderate mechanical instability, and severe pain and swelling. Grade III ankle sprain involves complete loss of function and motion, and severe mechanical instability. Diagnosis typically begins with a physical evaluation by a medical professional and an evaluation of ankle trauma history. The symptoms are assessed, this includes the level of tenderness, the degree of swelling, mechanical instability and range of motion. Special tests like the ‘squeeze test’ can be conducted by squeezing the tibia and fibula at the calf to see if pain is elicited. Similarly, the ‘external rotation’ test can be conducted, with a positive result indicated by pain. Radiography is used to rule out an ankle fracture, an uncompleted ankle sprain will appear normal on the radiograph, whereas a serious sprain will reveal injury to the ligaments. For chronic ankle sprains persisting over 6 weeks, CT scans and MRIs may be used to rule out talar dome lesions. For uncomplicated ankle sprains, management consists of reducing swelling as it restricts the range of ankle motion. Swelling can be reduced with the RICE (rest, ice, compression, elevation) method, apply ice to the area immediately after injury, heat packs or heat creams should be avoided as they encourage swelling. Slowly introduce ankle exercises to maintain range of motion and to assist lymphatic drainage. Elevating the ankle above the heart can also reduce swelling and increase lymphatic drainage. Medications like non-steroidal anti-inflammatory drugs can be prescribed or bought over the counter to reduce inflammation/swelling and aid pain relief. Patients may find the use of crutches helpful during the initial stages of ankle sprain to take the weight off the ankle. Rehabilitation following an ankle sprain is especially important in order to reduce the risk of experiencing chronic symptoms of ankle sprain. A common error people normally undertake is immobilising the ankle sprain for long periods of time, via a temporary cast or splint. Rehabilitation includes expanding the range of motion of the ankle, muscle-strengthening exercises, proprioceptive training, and activity-specific training.⁴

Broken ankle 

A broken ankle, also known as an ankle fracture involves a fracture of the tibia, fibula, or talus bone. Ankle fractures can either be displaced, where the bone breaks and moves out of alignment, and nondisplaced, where the bone breaks but the bone remains in place. Fractures can also be open or closed, with open fractures meaning that the broken bone has moved out of alignment and pierced past the skin.² Ankle fractures are common across all age groups, with around 187 per 100,000 adults breaking their ankle in the US.⁵ Pre-existing ankle trauma weakens ankle strength and increases the likelihood of ankle fracture, this includes previous ankle fracture and sprains. Fractures are caused by twisting or bending of the ankle at the joint, they are more common in high-impact sports and activities. Certain risk factors can increase the chances of subsequent ankle fractures by prolonging fracture healing, this includes smoking, diabetes, and peripheral vascular disease. Certain medications can also slow wound healing, such as steroids, chemotherapy, and immune modulators. The symptoms of ankle fracture include swelling, fracture blisters, skin abrasion and tears. 

Similar to ankle sprains, ankle fracture diagnosis starts with a physical examination by a medical professional. Here, symptoms are assessed and diagnosis is assisted by imaging techniques, for example, X-rays are often used to characterise the fracture. CT scans and MRIs may also be used to diagnose and characterise the fracture. Treatment of a broken ankle depends on the severity and type of fracture. Initial management is the same regardless of severity; the goal of treatment is to reduce swelling, immobilise the ankle, reduce pain, avoid infection and align the bone for proper healing. With the exception of severe open ankle fractures where the treatment is urgent surgical care. To immobilise and align the fracture, splints and boots are used in the rehabilitation process. For uncomplicated, non-operative ankle fractures, splints and boots are worn for approximately 6 weeks, whereas operative fractures require 8-12 weeks.³  Similar to ankle sprains, the goal of rehabilitation is to restore and maintain ankle motion, strength and function. 

Key similarities and differences 

The main difference between an ankle sprain and a broken ankle is the site of injury, with a sprain defined by trauma to the ligaments and a fracture defined by a break in the bone. In some cases of nondisplaced, mild ankle fracture and grade I-II ankle sprain, signs and symptoms may present in a similar manner. Both may present with ankle swelling, tenderness, and pain. Generally, the ankle can still be mobilised when sprained, whereas a broken ankle prevents movement. Additionally, ankle sprains can still hold some body weight, whereas ankle fractures typically can’t. The main diagnostic procedure that can differentiate between a sprain and a fracture is an X-ray, where fractures in the bone are visualised. Other imaging techniques include CT scans and MRIs. 

Initial management of both ankle sprains and fractures includes reducing swelling and pain. Treatment of ankle fractures focuses on making sure the bone is correctly aligned during the healing process, this can be done with a splint or boots. On the other hand, the use of immobilisation aids is discouraged for ankle sprains as rehabilitation focuses on restoring the full ankle range of motion. Surgery is typically not a treatment route for ankle sprains, however, it is considered a necessity for certain types of ankle fractures (open, displaced fractures). 

When to seek medical attention 

The signs and symptoms of an ankle sprain and fracture can present similarly, it is important to seek medical attention for proper diagnosis and treatment. It is important to know that a sprained ankle and an ankle fracture can occur simultaneously. The main sign to seek medical evaluation is the inability to bear weight on the ankle, indicating an ankle fracture or a severe ankle sprain. Regular ankle sprains do not need professional medical attention, the healing process can be managed at home. Most ankle fractures need medical attention, to ensure that the bone is aligned correctly. 

Recovery, rehabilitation and prevention. 

The average time taken for a sprained ankle to heal can vary from a few days to a couple of weeks, depending on the severity.⁶ On the other hand, ankle fractures may take up to 4-8 weeks to heal.⁷ For both cases, full recovery and rehabilitation may take up to at least 6 months, rehabilitation exercises like ankle strengthening and stretching routines help aid recovery. To prevent ankle injuries, it is important to wear proper footwear with the appropriate ankle support. 

Summary

To summarize, the main difference between a sprained ankle and a broken ankle is the site of injury. A sprained ankle is when ligaments surrounding the bone in the ankle experience physical trauma, whereas a broken ankle is when the bone in the ankle fractures. Imaging tools like X-rays are used to distinguish between the two conditions. Correct diagnosis is important as treatment goals are different, always consult with a medical professional to receive the appropriate treatment plan. If treatments are successful, patients should expect to be fully recovered after 6 months.