Approach to ankle pain: Clinical sciences

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Introduction 0:00–0:34

Ankle pain is a common symptom that can have many underlying causes, including conditions affecting the joints, bones, tendons, or skin.
It’s important to first identify if your patient’s ankle pain is due to trauma or infection. Other possible types of ankle pain include neuropathic pain due to nerve damage, and nociceptive pain due to arthralgia, ostalgia, tendinopathy, and dermatologic ulcers.
When a patient presents with ankle pain, first obtain a focused history and physical exam. History typically reveals ankle pain, while the exam might demonstrate ankle edema, erythema, or warmth.

Focused H&P 0:34–0:58

They may also have ankle tenderness, effusion, limited joint range of motion, crepitus, or even an obvious joint deformity.
Your next step is to assess for trauma. This includes an obvious mechanism of injury, such as a motor vehicle collision or sports injury, or if there’s a joint deformity or ligamentous laxity.

Trauma 0:58–1:47

If trauma is present, assess the Ottawa ankle rules, which can tell you if imaging is needed or not. First, check to see if the patient has pain in either the malleolar or midfoot zones.
Next, palpate for bony tenderness in the affected limb along the distal fibula, distal tibia, base of the 5th metatarsal, and the navicular bone.
Third, determine if your patient was unable to bear weight on the affected foot immediately after their injury AND is unable to bear weight for at least four steps at the time of initial medical evaluation.
If the patient has pain in either the malleolar or midfoot zones and at least one of the other two criteria, meaning bony tenderness or inability to bear weight they meet the Ottawa rules criteria.

Ankle Fracture 1:47–2:06

In this case, order an ankle x-ray. If it shows a fracture of one or more ankle bones, diagnose an ankle fracture.
On the other hand, if the Ottowa rules criteria are not met, the likelihood of fracture is low, so an X-ray is not indicated.

Ankle Sprain or Strain 2:06–2:50

At this point, diagnose an ankle sprain or strain. Here’s a clinical pearl!
Ankle sprains are very common and generally seen in teens and young adults. The most common type is lateral ankle sprain caused by inversion ankle injury.
Another important and more serious type is a high ankle sprain which is caused by damage to the tibiofibular syndesmosis.
This can happen with high-impact sports such as football. Alright, let’s take a step back.

Septic Arthritis 2:50–3:49

If trauma is not present, assess for signs of infection like fever, chills, myalgias, and localized tenderness. If there are signs of infection, think septic arthritis or osteomyelitis.
Patients with septic arthritis typically have a history of immunosuppression or pre-existing joint disease. Physical examination may reveal ankle joint effusion, limited range of motion, and erythema with warmth of the overlying skin.
Based on these findings, consider septic arthritis of the ankle and aspirate synovial fluid for analysis of cell count and differential, gram stain, culture, and the presence of crystals.
If the synovial fluid has a cloudy or purulent appearance, a white blood cell count of 50,000 or more, the gram stain and culture are positive for bacteria, and the sample is negative for crystals, diagnose septic arthritis.
Next up is osteomyelitis. Next to fever, patients often have a history of diabetic neuropathy, peripheral vascular disease, or chronic ankle ulcers.

Osteomyelitis 3:49–5:08

History might also reveal risk factors such as tobacco use or immunosuppression. On physical exam, you’ll typically see tenderness to palpation, erythema, and edema of the overlying skin.
There might also be fistula tracts or ulcerations on the skin. Based on these findings, consider osteomyelitis of the ankle and order labs, including blood cultures, CBC, and inflammatory markers like ESR and CRP.
Also, make sure to order imaging, including an X-ray and an MRI. Labs reveal positive blood cultures, often with leukocytosis and elevated ESR and CRP.
X-ray may show a lucent bone lesion with an overlying periosteal reaction or cortical erosion, while the MRI shows diffuse bone marrow and soft tissue edema, where there is also periosteal reaction and an adjacent complex collection might be present.
In this case, you can diagnose osteomyelitis. On the other hand, if there are no signs of infection, assess for neuropathic ankle pain.

Neuropathic ankle pain 5:08–6:58

This type of pain is lancinating, electrical, radiating, burning, or cold in nature. If neuropathic pain is present, the patient might report a history of numbness and tingling in their feet, as well as a history of a systemic disease associated with neuropathy, such as diabetes mellitus or multiple myeloma.
Physical exam reveals decreased sensation to pinprick and allodynia, which is when pain is elicited from something that typically doesn’t cause pain like a feather.
In this case, consider neuropathy. To confirm, you might need to order a nerve conduction velocity study, or NCV, and an MRI.
If the NCV shows an abnormal nerve conduction and the MRI shows nerve compression, diagnose neuropathy. Here’s a clinical pearl to keep in mind!
There are many possible causes of neuropathic ankle pain. Peripheral neuropathy is a common cause that can lead to sensory loss as well as decreased ankle reflexes.
Another possible underlying condition is complex regional pain syndrome, also known as CRPS for short. This disorder occurs several weeks after surgery or traumatic injury and causes burning pain or numbness with skin changes in the affected extremity.
Lastly, entrapment neuropathy can cause neuropathic pain. For example, tarsal tunnel syndrome is burning pain in the medial ankle and heel caused by entrapment of the posterior tibial nerve under the flexor retinaculum of the medial ankle.
Okay, if neuropathic ankle pain is not present, assess for nociceptive ankle pain. This type of ankle pain is localized, dull, or sharp.

Nociceptive ankle pain 6:58–7:24

It does not radiate, has an identifiable pain source, and usually involves joints, bony structures, soft tissues, or skin.
If this is the case, you should assess the primary tissue involvement to determine the source of the pain. First, let’s discuss arthralgia.
These patients may have a history of joint stiffness, fatigue, and malaise. The exam may show joint erythema, edema, and warmth with possible joint deformity, limited range of motion, or crepitus.

Arthralgia 7:24–8:29

If this is the case, diagnose arthralgia. Here’s another clinical pearl to keep in mind!
Common examples of ankle arthralgia include osteoarthritis, rheumatoid arthritis, and crystal arthropathy. Osteoarthritis is a degenerative disease of the joints, characterized by mechanical wear and tear injury to articular cartilage, resulting in bony and synovial damage.
On the other hand, rheumatoid arthritis is a chronic, autoimmune disorder that involves symmetric inflammation of the synovial joints, leading to joint effusion with eventual destruction of cartilage and bones.
Finally, crystal arthropathy is the cause of ankle pain in patients with a history of high purine diet, diuretic, or alcohol use.
Next up is ostalgia, also known as bone pain. Patients may report a history of osteoporosis, obesity, increased activity, or tobacco use.

Ostalgia 8:29–9:15

The physical exam reveals an ankle that is tender to palpation, possibly with edema or erythema of the overlying skin, and difficulty bearing weight on the affected leg.
With these findings, diagnose ostalgia. Here’s a clinical pearl!
A possible cause of ostalgia is a healing fracture seen in patients with prior traumatic injury that has not completely healed.
In this case, you can get an x-ray which will show signs of a healing fracture, such as an overlying periosteal reaction.
Alright, let's move on to ankle tendinopathies. Patients may have a history of corticosteroid use, obesity, increased physical activity, or pain with activity.

Tendinopathy 9:15–10:20

Exam will reveal localized tenderness over the affected tendon, and in some cases, ankle edema and even deformity. With these findings, diagnose ankle tendinopathy.
Here’s a clinical pearl to keep in mind! Most ankle tendinopathies result in subacute or chronic pain due to overuse injuries, while some tendon injuries cause more acute pain.
For example, rupture of the Achilles tendon can often present with pain near the posterior aspect of the ankle joint or pain near the heel.
Suspect Achilles tendon rupture in active patients with sudden onset of pain at the site of the Achilles tendon and a lack of passive plantarflexion of the affected foot when you squeeze the calf muscle.
Other tendons that may be affected include peroneal, tibial, and tibialis anterior. Finally, let’s discuss dermatologic ulcers.
These patients may have a history of skin changes, itching, non-healing ankle wounds, malnutrition, decreased mobility, or diabetic neuropathy.

Dermatologic Ulcers 10:20–11:20

On physical exam, the affected skin is tender to palpation. You might also see a rash or skin ulcers.
If this is the case, diagnose dermatologic ulcers as the cause of your patient’s ankle pain. Time for one more clinical pearl!
Different types of skin ulcers can cause dermatologic ankle pain. Patients with diabetes are at increased risk of developing these ulcers due to peripheral neuropathy, trauma, or ischemia.
On the other hand, vascular abnormalities, such as venous hypertension, can result in foot ulcers, even when diabetes is not an underlying factor.
Additionally, patients who have decreased mobility may develop pressure ulcers on their feet. Alright, as a quick recap… Ankle pain is a common symptom that can have a variety of underlying causes.

Review 11:20–11:48

When evaluating a patient with ankle pain, first, assess for trauma leading to an ankle fracture, sprain, or strain. Next, assess for infections like septic arthritis and osteomyelitis.
If trauma and infection are not present, characterize your patient’s ankle pain as either neuropathic pain due to underlying neuropathy, or nociceptive due to arthralgia,
Approach to ankle pain: Video, Steps, and Uses | Osmosis