A bunion forms when the bursa (a sac of fluid at friction points between the tendons and bone in some areas and between bone and the skin in others) becomes inflamed along the edge of the joint at the base of the big toe.
An acute bunion can progress into the second type of bunion, the hallux valgus, a chronic but often painless deformity involving permanent rigidity of the bones.
Bunions can form in any part of the foot but occur most often at the big toe joint, where the first metatarsal bone abuts the proximal phalanx of the big toe.
Women are more likely than men to get bunions because of the misshapen footwear and elevated heels they wear.
Bursitis is an inflammation of the bursa, which is a sac containing tissue fluid about the consistency of an egg white. The bursa at the big toe joint acts as a lubricant between the skin and the bones. Continual irritation of the skin by an ill-fitting shoe causes the sac to become inflamed and inflated with more fluid. When that occurs, the condition is an acute and painful bursitis.
During the early stages of bursitis, the fluid tries to force itself to the surface of the skin so that it can be discharged. There is minimal but continuous irritation at the joint.
If you ignore the irritation, hardening of the skin takes place. The forward displacement that occurs when your foot is fitted into high-heeled shoes, or even into stockings that are too snug, adds to the pressure upon the joint. The bursal fluid begins to solidify into a mass that resembles gelatin. The result will be a bunion, which then enters a subacute phase.
If allowed to progress, the condition can become worse. It does so because of the problem of obtaining a properly fitted shoe. The ball of the foot, with its bulbous outcropping of bunion, is considerably wider than the heel. The shoe with a snug heel that prevents slippage at its back might not fit the normal width of the ball of the foot at the front of the shoe. With the added growth of bunion, the width of the foot can no longer be considered normal. Thus, the proper fit at the ball of the foot leads to an angulation of the big toe. This deformity is a hallux valgus.
Hallux valgus is a serious condition. It strains the foot and produces an abnormal prominence of the joints; it also widens the front of the foot and causes a loss of balance. And any deformation of the big toe interferes with standing and walking. Also, malposition of the big toe bone and loss of power in the foot muscles can lead to arthritis early in life.
Long periods of pressure from a tight-fitting shoe can cause the inflammation and the pain. This often happens when the big toe is forced into a position where it presses inward and overlaps the second toe. The base of the big toe then is pushed beyond normal alignment of the foot, resulting in the prominence typical of a bunion.
If abnormal pronation is identified and corrected early, the formation of a bunion can be prevented. However, if the bunion has already developed and cannot be tolerated by the patient, surgery is necessary.
Amputation of the big toe ceased to be a treatment for bunions many generations ago, but only in the past few years have surgical procedures been developed to incorporate the realignment of the bone with the correction of the abnormal motion that led to deformity.
Surgical techniques can now not only move the wayward bones into proper alignment but also slide the first metatarsal downwards so that its head is pushed into a normal position. In its proper position, the metatarsal bone can help prevent the over-pronation that caused the formation of the bunion. Combined with proper orthotic devices, this type of surgery has provided excellent results.