Plantar fasciosis is one of the most common causes of chronic heel pain, yet it remains widely misunderstood. Many people are familiar with the term plantar fasciitis, which implies inflammation of the plantar fascia. While inflammation may play a role during the early stages of injury, long-standing heel pain often represents a different biological process. In many chronic cases, the plantar fascia has entered a state of failed healing and degeneration rather than ongoing inflammation. This is commonly referred to as plantar fasciosis.
The plantar fascia is a strong band of connective tissue that extends from the heel bone to the toes. It supports the arch of the foot, stores and releases energy during walking and running, and helps stabilise the foot during weight-bearing activities. Because it experiences substantial mechanical loading every day, it is vulnerable to repetitive stress when the demands placed upon it exceed its ability to recover.
In plantar fasciosis, microscopic examination of the tissue has demonstrated disorganised collagen fibres, increased ground substance, abnormal fibroblast activity and reduced tissue quality. Rather than healthy collagen repairing after repeated loading, the fascia develops degenerative changes that can leave it painful, thickened and mechanically weaker. This explains why simply waiting longer does not always result in recovery. The tissue may require a different rehabilitation strategy to encourage normal healing.
Several factors can contribute to the development of plantar fasciosis. These include repetitive overloading, prolonged standing, sudden increases in training, inadequate recovery, reduced calf flexibility, weakness of the foot and lower limb muscles, altered biomechanics, excess body weight and advancing age. In many patients there is no single cause. Instead, several contributing factors combine over time until the tissue can no longer adapt to the stresses placed upon it.
Symptoms commonly include pain beneath the inside of the heel, particularly during the first few steps in the morning or after periods of rest. Many patients also experience increasing discomfort after prolonged standing, walking or exercise. Although these symptoms are typical, they are not unique to plantar fasciosis, making a careful assessment essential. Conditions such as Baxter's nerve entrapment, heel fat pad syndrome and calcaneal bone marrow oedema may produce similar symptoms or occur alongside plantar fasciosis.
The most important message is that plantar fasciosis is not simply 'plantar fasciitis that has lasted longer'. It represents a change in the biology of the tissue. Understanding that difference helps explain why chronic heel pain often requires a different diagnostic and treatment approach from acute heel pain.