Sprained Ankle vs. Broken Ankle: How to Tell?

What is the concrete difference between a sprain and an ankle fracture?

Let’s first establish a clear understanding of what we mean by “ankle sprain” and “ankle fracture.”

In medical terms, but more importantly, in terms of everyday life, let’s make sure we’re talking about the same thing 🙂

Ankle Sprain

We refer to an ankle sprain when one or more ligaments are:

• Stretched more than normal = Grade 1 sprain, mild sprain.
• Partially torn, not completely across its width = Grade 2 sprain, moderate sprain.
• Completely torn across its width = Grade 3 sprain, “severe” sprain (but often recovers well), with possible ankle bone avulsion.

There are ligaments in various parts of the foot and ankle, not just around the malleoli. Ligaments can potentially stretch or tear in each joint.

For example, you might experience:

• An external ligament sprain of the ankle (the most common).
• An internal ligament sprain of the ankle.
• A Lisfranc sprain (more at the level of the foot).
• A sprain involving the ligaments of the big toe.
• A metatarsal sprain of the foot.

In everyday language, we also use terms like “twisted ankle” to refer to a sprain.

Ankle Fracture

We use the term “fracture” when there’s an issue with a bone. Specifically, when the bone is:

• Cracked: Often referred to as a crack.
• Broken: There’s a true break in the bone. The bone is separated into two or more parts, more or less spaced apart.

The ankle can be fractured or cracked at one or multiple locations, both on the inside and outside of the foot (medial and lateral malleoli), or on the top. This is why we refer to:

• Unimalleolar fracture: Only one malleolus is affected.
• Bimalleolar fracture: Both malleoli are affected.
• Trimalleolar fracture: Fracture of both malleoli and the tibial plafond, a part at the bottom of the tibia.

In everyday language, we use terms like “broken ankle” or “ankle break” to refer to a fracture.

The main structural difference between a sprain and a fracture

The primary anatomical distinction between a fracture and a sprain lies in the affected structure:

• In the case of a sprain, it’s a ligament.
• In the case of a fracture, it’s a bone.

Of course, it’s possible to have both a fracture and a sprain, or multiple fractures and sprains.

Generally, ligaments are tissues that tend to heal faster than bones. Thus, recovery from a sprain is usually faster than from a fracture.

However, there are significant individual differences in this regard.

What are the symptoms of an ankle sprain versus a broken ankle?

Several factors are considered to hypothesize whether it’s more likely an ankle sprain or a fracture. None of these factors taken individually is sufficient; it’s truly a combination that guides our diagnosis:

• How the injury occurred: What were the circumstances? Was there an impact on the ankle? Did it twist? In which direction?
• Existing history: Any prior issues with this ankle? Or specific general conditions?
• What you can do: Are you able to walk with a slight limp? Or can’t put any weight on the foot at all?
• Swelling and edema: Almost always present with ankle trauma, even without a sprain or fracture. While it often causes concern, it doesn’t necessarily indicate a more severe injury.
• Precise location of pain at rest and on touch.

In fact, the last point—the precise location of pain—is what determines whether or not a foot X-ray is needed.

Because only an X-ray (or another type of imaging like MRI) can definitively confirm a fracture. By visual observation alone, it’s impossible to know.

The Ottawa Ankle Rules are a set of criteria specifically used to help determine whether X-rays are necessary within 10 days following the injury. According to these internationally accepted criteria, an ankle X-ray is recommended if (and only if) you have any of the following:

Pain in the malleolar zone (the bony protrusions on each side of the ankle), AND:

• Inability to bear weight immediately after the injury and at the emergency department for four steps, OR
• Bone tenderness along the distal 6 cm of the posterior edge of the tibia or fibula, or the tip of the medial or lateral malleolus. OR pain in the midfoot area (the region between the ankle and the toes), AND:
• Inability to bear weight immediately after the injury and at the emergency department for four steps, OR
• Bone tenderness at the base of the fifth metatarsal, OR
• Bone tenderness at the navicular bone.

Why don’t we routinely perform an X-ray “to be sure”? Simply because it can result in unnecessary radiation exposure (in addition to increasing costs and wasting time).

Furthermore, the Ottawa Ankle Rules are quite reliable: less than 2% of individuals for whom no imaging was recommended by these rules actually had a fracture (Melanson 2022).

Their use has been shown to reduce unnecessary X-rays by 30 to 40% (Minerva, 2003).

How is the diagnosis of an ankle sprain versus ankle fracture made?

Here are the different scenarios that lead to the diagnosis of an ankle fracture or sprain:

1. If you’ve had an X-ray of the foot because you met the Ottawa Ankle Rules criteria:

• The X-ray showed a crack or fracture in the ankle. The diagnosis of a fracture is then confirmed, and there’s no need to go further.
• The X-ray didn’t show any ankle fracture or crack. In this case, you might have a sprain or a simple bruise.

2. If you haven’t had an X-ray of the foot or if you had an X-ray that didn’t show a fracture, the (para)medical team you encounter will decide whether to continue with further imaging examinations.

For instance, an ultrasound could be performed to visualize the ligaments.

On the other hand, some teams might decide not to escalate further in additional tests. Why? Whether there’s a sprain or not, whether it’s a grade 1 or 2 sprain, the general approach remains similar. Treatment can be adjusted based on symptoms rather than the exact type of injury. Personally, this is the approach I prefer.

In cases where a hematoma is present, accompanied by tenderness upon palpation around the distal fibula and/or a positive anterior drawer test, there is likely a rupture of the lateral ligaments of the ankle. This can be determined with a test conducted within 4-5 days (Vuuberg 2018).

It’s the experience of healthcare professionals, accustomed to observing ankle traumas, that enables them to refine the diagnosis.

Based on this clinical examination alone, one can confidently diagnose a sprain without additional imaging. If symptoms are mild and there appears to be no instability while walking, it might sometimes be referred to as a simple bruise.

Is it necessary to consult a doctor when you twist your ankle?

This is a question that can be quite difficult to answer.

In general, the “precautionary principle” is often applied to address such questions. As healthcare professionals, we tend to advise consulting with a professional to avoid overlooking something and to prevent potential consequences falling back on us, thus safeguarding our responsibility.

However, seeking medical attention “just in case” also brings about certain issues: time loss, unnecessary anxiety, excessive medicalization, unnecessary treatments, decreased self-confidence in identifying health issues, and so on.

To provide a brief answer to this question: no, it’s not always necessary to consult a doctor immediately after twisting your ankle.

It’s estimated that around 50% of individuals with an ankle sprain do not seek healthcare professional advice (Vuuberg 2018).

If the pain is severe, you’re having difficulty walking, or the ankle trauma was significant, it might be more appropriate to consult in such cases.

Can we miss an ankle fracture?

Yes, of course, we can never be 100% certain of a diagnosis. Even with an X-ray or an MRI, it’s always a hypothesis, more or less probable.

However, by utilizing the Ottawa Ankle Rules and conducting a thorough clinical evaluation, the risk of missing an ankle fracture is significantly reduced.

If you’re wondering, “Could there be a misdiagnosis? Do I actually have a more serious issue with my ankle, like a fracture?” Here’s the approach I recommend:

• Ankle fractures are rarer than sprains.
• The treatment for an ankle sprain is very similar to that for an ankle fracture.
• A misdiagnosis doesn’t necessarily result in poorer healing.

Can an ankle sprain or fracture be confused with another type of injury?

Certainly, there are other injuries to the ankle and foot apart from fractures and sprains. They can be broadly categorized into two main groups:

1. Injuries that occur suddenly due to a fall, accident, trauma, or incorrect movement. The most common ones include:

• “Simple” contusion without damage to ligamentous, muscular, or bony tissues.
• Ankle sprain: torn ligament in ankle or stretched
• Ankle fracture
• Ankle dislocation
• Ankle subluxation
• Fracture of the talus (ankle bone)
• Broken heel bone
• Fracture of the fibula

2. Injuries that develop gradually over time, including (but not limited to):

• Tendinopathies/tendonitis
• Tarsal tunnel syndrome
• Plantar fasciitis / Heel spur
• Chronic ankle instability
• Ankle arthritis (e.g., rheumatoid arthritis)
• Ankle osteoarthritis

How can they be differentiated? The mode of onset is one key point:

• Did the symptoms develop gradually?
• Or did they appear suddenly after a specific event?

Symptoms can also help favor one diagnosis over another, although they often overlap. For example, the type of pain:

• Mechanical: occurs with movement
• Inflammatory: at night or during rest

Doctors and physical therapists are trained healthcare professionals who can identify the type of injury. They can determine appropriate treatment and provide an approximate prognosis for healing time.

This process is known as “differential diagnosis” in medical terms.