Foot Deformities

Foot deformities are not unique to people with diabetes. Hammer bunions, and metatarsal disorders are not uncommon in the general population, especially among older citizens. But foot deformities can have more serious consequences if you have diabetes. If you have a problem in the way your foot is structured, it can cause pressure on certain points of the foot just from walking, especially when you wear poorly fitting shoes. If you have neuropathy, any calluses, corns, blisters and/or ulcers that develop can go unnoticed. They can worsen or be slow to heal if your circulation is poor. If left untreated, these lesions can develop into serious infections. The key to dealing with foot deformities is to have your shoes properly fitted and to inspect your feet daily for any signs of irritation or abrasion. This can prevent serious lesions and infections from developing.

There are several common types of foot deformities among people with diabetes: hammertoes, claw toes, prominent metatarsal heads, bunions, limited joint mobility, partial foot amputations, and Charcot's joints.

Hammertoes are caused by a buckling of the toes, such that the structure of the toe resembles the neck of a swan. Hammertoes are often caused by a weakness of the small muscles of the foot. These muscles can't stabilize the toes on the ground. This causes the toe to bend back and sit up on the metatarsal head. If you have hammertoes, you place extra pressure on the ball of your foot. This position causes irritation at the tip and top of the toe. If you have hammertoes, you probably have a difficult time getting shoes to fit properly. If your shoes don't fit right, you may find that your foot rubs at the top of the toe and can easily develop an ulcer.

Claw Toes

Claw toes are similar to hammertoes. However, there is more buckling and the toes are more deformed. The toe is bent quite a bit at the first and second joint. If you have claw toes, your toes sit on top of their metatarsal heads and push down on the ball of the foot. You are more likely to have claw toes if you have high arches. Like hammertoes, claw toes are difficult to fit properly. You will need to find a shoe with a large toe box.

Prominent Metatarsal Heads

Prominent metatarsal heads can occur if you have one metatarsal bone that is longer or lower than its neighboring bones. The metatarsal bones are the five long bones located in the mid- and forefoot, just behind the toes. The metatarsal heads are similar to the knuckles of the hand. They are found in the ball of the foot and support your body's weight. Normally your weight is distributed evenly across these heads. But sometimes, one metatarsal head can carry a disproportionate amount of weight. This can cause pain, callus formation, and ulceration of the foot.

Bunions are caused by an enlargement of bone at the base of the big toe joint. They are often blamed on tight-fitting shoes, but more often than not, bunions are inherited. If you have a bunion, then your big toe points toward the second toe. When this happens, your big toe may sit over or under the second toe. If you have a bunion and wear a tight or ill-fitting shoe, especially high heels, you put pressure on the metatarsal head of your big toe. This can cause an ulcer to form. Arthritis may occur along with bunions and this can cause pain and stiffness in the joint. You can also develop a callus or ulcer under the big toe.

Limited Joint Mobility

Limited joint mobility of your foot and ankle can put an abnormal amount of pressure on the bottom of the foot. This can lead to skin damage and ulcer formation. Arthritis is one disorder that can limit the range of motion of many of the joints in your foot. When it affects one of your big toe joints, specifically the first metatarsal phalangeal joint, your toe can't bend normally when you walk. To compensate, your weight shifts to the ball of your foot as your heel lifts off the ground. As a result you have extra pressure under the big toe (called the hallux). Calluses tend to form here and lead to ulceration. This condition is called hallux limitus.

Partial Foot Amputation

Sometimes, in order to save the foot. doctors recommend partial foot amputation. However, if you have one or more toes removed from your foot, this creates a foot deformity and can create further problems. If you have toes missing, the pressure you exert on the bones of the foot is uneven as you walk. This can cause ulcers to form and can increase the chances of further amputation down the road. Many patients have avoided this dilemma by having a transmetatarsal amputation performed. In this procedure, all the toes up to part of the metatarsal bones are removed so that, in effect, the forefoot is amputated. This type of surgery results in greater balance, flexibility, and mobility and reduces the risk of developing pressure points, ulcerations, and future amputation. If you have this operation, you will not have to wear a prothesis, but you will need extra padding in your shoes.

Charcot's Joints

Charcot's joints is a some what rare but debilitation foot injury that results from sensorimotor neuropathy. When the nerves of your feet are damaged, you lose the ability to sense pain. Over the years, minor injuries and fractures hurt the joints in your feet, but you probably didn't even notice. Ultimately, the damage becomes so great that the joint is permanently destroyed. You probably won't notice anything until your foot is red and swollen. Once this occurs, the joint can become completely destroyed in a matter of months. Once the middle of the foot collapses, the foot may take on a rocker-bottom configuration, which increases the pressure on the bottom of the foot. Walking can become difficult and ulcers are likely to develop.

Above information is from the book The Diabetes Problem Solver available form the American Diabetes Association.