Heel fat pad syndrome is one of the most commonly overlooked causes of chronic heel pain. Although many people assume pain beneath the heel is caused by plantar fasciitis or plantar fasciosis, the heel fat pad itself can become injured, thin, displaced or less effective at absorbing shock. When this occurs, every step places increased pressure directly onto the heel bone, leading to pain that can significantly affect walking and standing.
The heel fat pad is a specialised structure located beneath the calcaneus, or heel bone. Rather than being a simple layer of fat, it consists of tightly organised chambers of fat surrounded by strong fibrous septae. This unique architecture allows the fat pad to act as the body's natural shock absorber, protecting the heel from the enormous forces generated during walking, running and jumping. With each step, the fat pad compresses and then returns to its original shape, dissipating impact forces before they reach the underlying bone.
When the fat pad becomes damaged or loses its normal structure, its ability to absorb shock is reduced. As a result, the calcaneus is exposed to higher impact forces, and patients begin to experience pain directly beneath the heel. Unlike plantar fasciosis, where the pain usually originates at the attachment of the plantar fascia on the inside of the heel, heel fat pad syndrome tends to produce pain beneath the centre of the heel where body weight is transmitted during standing and walking.
Several factors may contribute to heel fat pad syndrome. Ageing is one of the most common. Over time, the fat pad may become thinner, less elastic and less capable of cushioning the heel. Repetitive impact activities such as running or prolonged standing may accelerate this process. Direct trauma, such as landing heavily on the heel or falling from a height, can also damage the fibrous structure of the fat pad and reduce its ability to function normally.
Footwear may also influence symptoms. Walking barefoot on hard surfaces or wearing shoes with minimal cushioning can increase repetitive loading through the heel. Conversely, footwear that provides appropriate cushioning and support may reduce symptoms by decreasing the impact transmitted to the calcaneus.
Heel fat pad syndrome can occur on its own, but it may also coexist with other causes of chronic heel pain. Some patients have both plantar fasciosis and fat pad syndrome, while others may also have calcaneal bone marrow oedema or Baxter's nerve entrapment. In these situations, treating only one condition often results in incomplete improvement because multiple pain generators are present.
One of the reasons heel fat pad syndrome is frequently missed is that standard X-rays are usually normal, and many patients are simply told they have plantar fasciitis. However, the pattern of pain is often different. Patients with heel fat pad syndrome commonly report pain that becomes worse the longer they stand on hard surfaces. Walking barefoot is often particularly uncomfortable, while cushioned footwear may provide noticeable relief.
Diagnostic ultrasound has become an increasingly useful tool for assessing the heel fat pad. It allows measurement of fat pad thickness, evaluation of its internal structure and comparison with the opposite foot. Ultrasound also enables the plantar fascia to be examined during the same appointment, helping determine whether one or both structures are contributing to the patient's symptoms.
Recognising heel fat pad syndrome is important because its management differs from that of plantar fasciosis. While stretching the plantar fascia may be appropriate for plantar fasciosis, treatment for fat pad syndrome focuses on protecting the heel from excessive impact, improving shock absorption and addressing any contributing biomechanical factors. An accurate diagnosis therefore remains the most important step before beginning treatment.