Plantar fat pad atrophy (breakdown)

A cause of pain in the ball of the foot

Plantar fat pad atrophy refers to the breakdown or thinning of the protective fatty cushion located underneath the heads of the metatarsal bones in the ball of the foot. This fat pad is there to cushion the load of our body as we walk or stand. Its absence, whether partial or complete, leads to pain in the ball of the foot when we move or stand, and may adversely affect our gait.

Why do we need a fat pad in the ball of the foot?

When we walk, we bend our foot, pushing ourselves forward with the help of our toes and the ball of the foot. For an instant, the whole body weight shifts onto these tiny bones. To absorb this load there is a cushion of fat located beneath the heads of the metatarsal bones where they unite with the toes.

The plantar fat pad is actually formed by the union of five individual metatarsal fat pads. It acts as a cushion that absorbs the shock and disperses the force, protecting the bones and the soft tissues of the ball of the foot. Likewise, there is a fat pad in the heel area, as when we stand or walk, the body weight is transferred through the heels and ball of the foot, so both these areas need protection.

Any condition that destroys or displaces this protective layer of fat leaves the metatarsal heads devoid of a shock absorber, as well as leading to transfer of the body loads directly to the underlying soft tissues, causing their irritation and eventually inflammation and pain. Along with pain, there may be callus formation and even ulceration.

What causes plantar fat pad atrophy?

  1. Ageing is considered the most important cause. With increasing age, this supporting adipose (fatty) tissue in the sole of our foot is reduced, the same way the adipose tissue is reduced in the rest of the body.
  2. There may be variances in the degree of plantar fat pad loss with ageing among individuals, and genetics are strongly considered to be the cause behind excessive fat pad loss.
  3. A downward displaced metatarsal head will crush the fatty tissue located underneath.
  4. In rheumatoid arthritis, the severe contracture of the toes leads to forward displacement of the fat pad.
  5. The same thing may happen in people with high arched feet as the severe contracture of the toes leads to forward displacement of the fat pad.
  6. In neuropathic diabetic patients with toe deformity there is often thinning and forward displacement of the metatarsal fat pad, which increases the risk of developing foot ulcers in these patients.
  7. Neuroma treatment: Damage to the plantar fat pad is a common problem when surgical removal of the nerve is performed. There is also a case report where steroids injected into the area for the treatment of Morton’s neuroma, led to plantar fat pad atrophy.
  8. Multiple surgical incisions or fractures may also lead to thinning or shifting of the plantar fat pad.
  9. Wearing high-heeled shoes, walking barefoot or in very thin soles may initiate or worsen the condition.

The symptoms:

  • There is pain and tenderness in the area.
  • Walking barefoot is difficult.
  • Callus formation or even ulceration in some cases.
  • Callus formation as a result of fat pad atrophy
  • The metatarsal heads appear prominent due to loss or shift of the fatty covering.

Treatment:

Supportive measures you can take:

  • Wear soft supportive innersoles
  • Wear good quality shoes that support and also cushion the feet
  • Avoid excessive pressure on the ball of the foot:
    • Wear low heels, an inch or less.
    • Use footwear that provides support to the ball of the foot
    • Avoid walking barefoot
    • Keep your weight in check
    • Avoid activities that involve squatting, walking down a slope or any action that puts pressure on the ball of the foot.

Use of insole devices:

Use of metatarsal pads and arch supports help to reduce the pain as:

  • This cushions the area, thus dispersing the force and reducing pressure on the vulnerable tissues
  • Innersoles cushion the heads of the metatarsal bones, leading to less pressure and callus formation

Although plantar fat pad atrophy affects both men and women equally, the choice of footwear makes women more vulnerable to developing pain and calluses in the ball of the foot. Avoiding the risk factors and wearing shoes that provide adequate cushioning to weight-bearing areas of the foot may help solve the problem.