Health matters: Plantar fat pad essential foot structure

Conway McLean, DPM, Journal columnist

No doubt you are familiar with Father Time and the ticking of the clock which signals the advancing years. The human condition requires the endurance of this passage through time and its consequences to our physical body. Early on, this passage brings growth through the vitality of youth, but with time all things decay, or at least wear out, a concept many of us can’t quite come to grips with.

It is possible for some painful condition to develop without obvious trauma, resulting primarily from the passing years. Body parts may wear out faster in some of us, an example being those individuals deprived of proper nutrition. Also common is the weakening of some structure, be it a tendon or ligament, placed under daily, repetitive stress. This latter issue may be the result of abnormal motion of the foot, like an arch which rolls down too much.

A degenerative change occurring to the human body is seen in almost everyone, to some degree. Although few would consider it an essential component of their anatomy, the specialized pad found under the ball of the foot and the heel are important to weight bearing. Without it, the bones in these areas would experience tremendous impact. Pain reliably results when not enough of the plantar fat pad is present. This unique padding is a compartmentalized arrangement of tough, fibrous tissue creating multiple chambers for fat. It’s these fat-filled spaces which allow for the dissipation of the force experienced by the heel and forefoot.

Whatever the reason, thinning (technically referred to as atrophy) will lead to pain from the area, generally described as a dull ache, with the ball of the foot becoming symptomatic far more often than the heel. Typically, the more active the individual, the more they are on their feet, the more discomfort will be noted. Although atrophy of the fat pad can lead to a more focal pain, such as an acutely inflamed metatarsal-toe joint, the discomfort of plantar fat pad atrophy is distributed evenly throughout the region.

Shoes can aggravate the deeper structures in the ball of the foot if the shoe has a higher heel. This arrangement increases weight bearing to the front of the foot and less to the heel. Even if someone has adequate padding, pain can result from this position alone. Predictably, the less fat pad one has, the less the heel has to be lifted to cause pain in the ball.

This condition is also associated with certain foot types, like the high arched foot. Because body weight is supported by less of the foot with this kind of architecture, more force is placed upon the areas in question. Pain in this region is more common in those possessing a high arch than with a flatter foot.

Perhaps the most frequent explanation for pain from the ball of the foot is a tight heel cord, aka the Achilles tendon. Because so many westerners wear shoes with a positive heel drop, meaning the heel is positioned higher than the front part, this, the largest tendon in the body, shortens over the years. A tight Achilles pulls the heel upward more forcibly, exerting more pressure on the ball of the foot (similar to the action of a seesaw on the playground).

Interestingly, a toe deformity can lead to pain in the ball of the foot. When most of the toes start to become hammered (meaning they curl downward), there can be a gradual migration of the toes upward at the ball of the foot. Because the digits are positioned more on top of the metatarsals rather than at the end, the toes will exert greater force downward onto the metatarsals, pushing them down into the ground. Additionally, because the fat pad is anchored to the toe, this “clawing” of the toes pulls the fat pad out and away from the bottom of the ball. This displacement of the padding leads reliably to the same aching discomfort originating from the region.

When thinning of the plantar fat pad is seen in some people, an evaluation of the sufferer’s circulation should be performed. Clogging of the arteries means less blood is getting to the feet, often leading to loss of this important cushion. There will be other signs of reduced flow, like loss of hair on the toes or cold digits, pointing the astute health care provider to investigate further.

When this thinning takes place in someone with diabetes, there can be dangerous consequences. Those so afflicted generally lose function of some sensory nerves, making it impossible for them to feel certain kinds of pain. This may allow excess pressure to the skin, leading to its gradual breakdown. An infection will often result.

Shoes should be part of this conversation; they may worsen the symptoms or lessen them. The higher the heel, the greater the force experienced by the ball of the foot, so there will be an increase in symptoms. If your shoe gear has a stiffer sole, less focal pressure will be directed at this critical region, meaning you will have less pain, even in the face of significant thinning of the fat pad.

Often an arch support of some kind will be utilized, an effective approach depending on the device and the severity of the problem. When a customized foot support is precisely fabricated, significant relief is provided. A precise redistribution of force is possible, and since these should be modeled from an exact replica of the foot, they are comfortable for both standing and walking.

Surgical options are few unless the cause is a deformity of the toes. When the toes are clawed (bent up at the ball of the foot and downward in the toe joints), straightening them can redirect force away from the area. This can also function to relocate the fat pad back towards its proper position. Although still experimental, physicians have attempted to supplement the fat pad with synthetic materials. The durability of these substances has been poor to date. Even newer, some have attempted to transplant fat from some other body part into the padding in the ball of the foot.

Although a common problem, many Americans suffer in silence from plantar fat pad atrophy and subsequently, pain in the ball of the foot. But a careful analysis will reveal the reason for this pain. Solutions are often simple and non-invasive. But just living with it will reduce your activity levels over the course of time, lessening your cardiovascular health. Don’t let plantar fat pad atrophy limit you or your quality of life: a solution is out there.

EDITORS NOTE: Dr. Conway McLean is a podiatric physician now practicing foot and ankle medicine in the Upper Peninsula, having assumed the practice of Dr. Ken Tabor. McLean has lectured internationally on surgery and wound care, and is board certified in both, with a sub-specialty in foot orthotic therapy. Dr. McLean welcomes questions, comments and suggestions at drcmclean@penmed.com.


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