By Dr. Conway McLean,

DABFAS, FAPWHc

It is too common an occurrence, people living with foot pain. They perform their job ably, spend time with their family, participate in the usual activities. But chronic pain detracts from quality of life and interferes with our enjoyment of life. Recurrent foot pain can even serve to impair our health since increased pain as a result of increased activity will function to reduce activity. Being less active isn t good for cardiovascular health, our metabolism, muscle fitness, etc. The human body needs to move.

One particularly troublesome area is the ball of the foot at the base of the big toe. The anatomy here is particularly complex, leading to a greater variety of potentially painful problems. Two small bones, called sesamoid bones, residing under the 1st metatarsal, add significantly to the complexity. The two of them sit side by side, attached to a tendon that is running out to the big toe. These bones each have an actual articulation, a joint quite literally, with the underside of the 1st metatarsal. Because of their position, inferior to this important weight bearing structure, the sesamoid bones receive tremendous stress in the course of your day.

They are prone to inflammation with sufficient physical force, like every other soft tissue structure. This can be the kind of pain which is annoying but in no way debilitating& ..at least initially. In the case of sesamoiditis, acute inflammation can develop, producing a sharp pain. This kind of abrupt onset of pain is often associated with an increased use of unsupportive shoes or perhaps participating in a new but physical activity.

Sesamoiditis is a general term for inflammation of the sesamoid apparatus (a term referring to the bones and the cartilage, the multiple tendons and ligaments that attach there) and is more common with certain foot types (a reference to someone s foot architecture, e.g. high arched, etc.). Worth mentioning again is the accumulated impact to this area in the act of standing and walking.

This is a complex part of human anatomy and how well it functions is critically important. Pain from these two small bones occurs for many different reasons. One common example is a 1st metatarsal bone which is angled downward excessively, a normal variation. The result is an increase in force experienced by a sesamoid, potentially leading to inflammation and pain.

Since the foot acts as the interface between our body and the immovable earth, a sesamoid bone can break (aka fracture) as can any other, especially with quick movements or a sudden change in direction. Because of the poor blood supply to these bones, fractures heal poorly and can produce recurrent symptoms. Although the right kind of foot support can function to reduce stress to the broken bone, these often have to be removed surgically.

To those afflicted with diabetes, a prominent sesamoid bone can result in amputation. Like everything else in the human body, these bones vary in size and configuration. If of sufficient bulk, greater pressure is exerted on the skin, which can thin, callus, and even sicken with time. This should sound painful and it would be except for the nerve degeneration frequent with diabetes (i.e. neuropathy). This prevents them from experiencing this critical message: your foot is being injured!

A particular gentleman, a diabetic, was experiencing just such a phenomenon, recurrent skin breakdown (an ulcer) below one of his sesamoid bones. Due to the impairment of the immune system which generally accompanies diabetes, any opening in their skin can have significant consequences (infection, hospitalization, etc.). We were having great difficulty getting the skin healed while still allowing him to bear weight on the foot, an important component of everyone s ADL s, the activities of daily living.

To aggravate the situation, his 1st metatarsal bone was excessively angled down. A prescription foot support had been fashioned to reduce the pressure under the area but that pesky sesamoid continued to pressure the skin inferior to it when the individual was weight bearing (aka standing, walking, skipping, all those good things). When conservative measures fail, prophylactic surgery for the diabetic is now the standard of care when it s able to pr skin breakdown.

Utilizing the principles of minimally invasive surgery (MIS), a tiny opening was made off to the side of the sesamoid, allowing the bone to be reached by a thin rotating rasp. This was used to shave down the sesamoid, reducing its bulk. Diabetics have difficulty healing incisions so a longer one is more likely to lead to infections. In this gentleman, the small incision, made away from weight bearing structures, healed easily. And sufficient pressure was removed from the skin below the thinned sesamoid that the ulcer closed promptly.

Location is one of the keys to identifying sesamoiditis since these are not large

structures and the pain is usually localized. But the pain can take many forms, from a mild aching to sudden sharp pain. Sports can take their toll, causing a fracture or dislocation. Inappropriate shoes in the presence of a certain foot type can also work to inflame the region. The treatments are numerous and effective when the right approach is taken, but that requires a determination of why someone has an inflamed sesamoid apparatus.

This is ultimately the more important question. Taking an anti-inflammatory will help reduce the pain but that s probably not the answer. It s unlikely that taking a drug will be the solution to a true structural, biomechanical issue. There is a take-home message here: if you have recurrent or chronic foot pain, you have a problem.

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Dr. Conway McLean is a physician practicing foot and ankle medicine in the Upper Peninsula, with offices in Escanaba, Marquette, and L’Anse. McLean has lectured internationally on wound care and surgery, being board certified in surgery, orthotic therapy and wound care. His articles on health and wellness appear in multiple local and national publications. Dr. McLean welcomes subject requests for future articles at drcmclean@outlook.com.