The plantar fat pad consists of a highly specialised and complex structure of fat globules surrounded by an arrangement of fibroelastic septa, which are designed to firmly hold the adipocytes in position.
These septae protect the fat globules from compressive loads, deformation and displacement within their cells or compartments; this allows the fat globules to function as shock absorbers without any fluid or fat leaks.
The subcalcaneal heel pad plays an important role in dissipating high-impact forces generated at heel contact in order to protect underlying neurovascular tissues, ligaments and tendons from the mechanical stresses produced during the gait cycle.
With the ageing process or the onset of systemic diseases such as rheumatoid arthritis and diabetes, the adipose tissue and the collagenous septae undergo degeneration exposing the sensitive soft tissue structure to increased plantar pressure.
K. Rome, from the School of Health in Middlesbrough, commented on the deformation of the heel pad in his review on the mechanical properties of the heel pad: “Breakdown of the internal cell compartments of fat globules and septa by degenerative or ageing processes, especially if it affects the internal reinforcement, will permit local bulging and a greater displacement, resulting in an atrophic pad under loading. High stresses, or repetitions above a critical level, tend to cause destruction of supporting structures. Healing response leads to further structural changes, which result in altered mechanical behaviour.”
In the case of conditions such as rheumatoid arthritis, there’s a reduced density observed in the adjacent bone caused by soft tissue inflammation. This leads to cartilaginous destruction, which ultimately results in a loss of resilience in the plantar fat pad.
This is responsible for decreased shock absorbency, leaving the heel and the Achilles tendon exposed to maximal tensile loads at heel strike and restricting mobility in the individual.
Early treatment strategies are essential when considering the diminished ability of the individual chambers of the heel pad to recover from repetitive stress or trauma; this includes the provision of extra cushioning support in the form of MASS4D® customised orthotics to offload any additional stresses to the underlying structures and to protect the heel pad from any long-term damage.
Copyright 2017 MASS4D® All rights reserved.
Repetitive plantarflexion can lead to pain and mechanical limitation in the posterior ankle joint which is known as posterior ankle impingement syndrome. This pathology commonly occurs in ballet dancers and football players.