Pain felt at the back of the ankle, just above the heel bone (calcaneus), is a common complaint often linked to physical activity or footwear. This posterior ankle pain can range from a minor, temporary irritation to a symptom of a more significant underlying issue. Understanding the potential causes, which range from gradual wear and tear to sudden injury, is the first step toward effective treatment. The source of the pain typically involves the Achilles tendon, the fluid-filled sacs that provide cushioning, or the bony structure of the heel.
Achilles Tendon Pain: Chronic Overuse and Degeneration
The Achilles tendon connects the calf muscles to the heel bone and is a frequent site of posterior ankle pain. When pain develops gradually due to chronic strain or overuse, the condition is called Achilles tendinopathy. This term encompasses both tendinitis and tendinosis, which are distinct problems requiring different management approaches.
Achilles tendinitis represents a short-term, inflammatory response characterized by pain, warmth, and mild swelling. If the condition persists for several weeks, the pathology shifts toward tendinosis. Tendinosis involves a degenerative breakdown of the tendon’s collagen fibers, causing the tissue to thicken and structurally weaken without typical signs of inflammation like redness or heat.
Symptoms of chronic tendinopathy include stiffness, often most noticeable in the morning or after rest. Pain generally worsens with activity, particularly movements requiring pushing off the foot, such as running or jumping. Over time, a palpable, localized thickening or bump may develop on the tendon, indicating degenerative changes. The distinction between inflammatory tendinitis and degenerative tendinosis is important for treatment. Anti-inflammatory medications and ice are more effective for acute tendinitis, while tendinosis requires treatments focused on stimulating tissue repair and strengthening exercises.
Bursitis and Structural Irritation Near the Heel Bone
Pain in the back of the ankle can also originate from the bursae, which are small, fluid-filled sacs that act as cushions. Retrocalcaneal bursitis is the inflammation of the bursa located between the Achilles tendon and the calcaneus (heel bone). When this sac becomes irritated, usually from friction or compression, it swells, causing tenderness and pain directly in front of the tendon attachment.
This inflammatory condition is often associated with Haglund’s Deformity, also known as “pump bump.” This is a bony enlargement on the back of the heel bone. This abnormal prominence increases pressure on the retrocalcaneal bursa and the Achilles tendon, especially when wearing shoes with a rigid heel counter. The combination of the bony bump and the inflamed bursa constitutes Haglund’s disease.
Symptoms of Haglund’s disease include visible swelling and a reddened, painful bump at the back of the heel. The pain is frequently aggravated by walking, particularly when wearing stiff-backed footwear like dress shoes or skates, which rub against the prominence. Although the bony prominence is permanent, the associated inflammation and pain can often be managed through conservative measures like changing shoes and using ice. This pain is caused by mechanical irritation rather than purely by tendon overuse.
Acute and Sudden Traumatic Injuries
In contrast to the gradual onset of tendinopathy or bursitis, some causes of posterior ankle pain are acute events demanding immediate attention. The most severe acute injury is an Achilles Tendon Rupture, which is a complete or partial tear. This injury typically occurs during sudden, forceful push-off movements, such as quick stop-and-start motions common in sports.
People experiencing a rupture often report a distinct sensation, describing it as a loud “pop” or “snap” at the back of the ankle. Many individuals mistakenly feel as though they were suddenly hit or kicked in the calf, despite no one being near them. Immediate, sharp pain and swelling at the back of the heel follow this sensation.
A rupture results in an inability to effectively push off the ground, making it difficult or impossible to stand on the toes of the injured leg. While a partial tear may allow some limited function, a complete rupture leaves a gap in the tendon that can sometimes be felt just above the heel. Recognizing symptoms of sudden onset and mechanical failure is important, as an Achilles rupture requires prompt medical evaluation.
Initial Self-Care and Determining When to See a Doctor
For mild, gradual-onset pain in the back of the ankle, initial self-care strategies can often provide relief and prevent the condition from worsening. Resting the affected ankle is the most important step, meaning temporarily avoiding activities that worsen the pain, especially running or jumping. Applying ice to the painful area for 15 to 20 minutes several times a day can help reduce inflammation and discomfort, particularly in the early stages.
Over-the-counter non-steroidal anti-inflammatory drugs (NSAIDs) may help manage pain and residual inflammation, though they are less effective for the degenerative changes of chronic tendinosis. Switching to footwear that does not irritate the back of the heel, or using a small heel lift insert, can reduce strain on the Achilles tendon and relieve pressure on an irritated bursa.
It is necessary to seek professional medical attention if certain “red flags” appear, indicating a potentially serious issue that self-care cannot address. Immediate evaluation is required if you hear a “pop,” have sudden, severe pain, or cannot bear weight on the foot. Other concerning signs include a visible deformity or a gap in the tendon, or if pain and swelling persist without improvement after three to five days of rest and home treatment.