A bunion or hallux valgus is a prominence on the inner border of the foot effecting the big toe and at the level of the 1st metatarso-phalangeal (MTP) joint. The bunion prominence which is seen and felt on the inner border of the foot is not due to any growth of bone but is due to the 1st metatarsal bone. With a bunion this has become more prominent than normal because the 1st metatarsal has moved away from its immediate neighbour the 2nd metatarsal. This widens the forefoot thus producing the bunion. An inevitability of the splaying of the foot which occurs with a bunion or hallux valgus is that the great toe itself is then pulled across in the opposite direction (towards the second toe) by the still normally located tendons of the big toe. A bunion or hallux valgus is commonly confused with hallux interphalangeus (where the deformity lies more distally and which tends to be less problematic). Here there is no increase in the space between the metatarsals, and the deformity lies in the shape of the phalynx bone.
What causes bunions? This question is often answered by blaming shoes. But in fact, shoes only play a small role in developing bunions. Yes, shoes, especially high heels cause abnormal squeezing of your forefoot. This in turn to help promote a bunion. But if everyone who wore high heels shoes had a bunion, there would be a lot more then the 15% prevalence we see in the general population. As you can see from the flow chart, genetics plays the major role in development of bunion deformities. Genetics determines the way your foot functions. Are you flatfooted? Are your joints flexible or stiff? Do you have a high arch? Do you have tight muscles? These traits are determined by your genetic code. These characteristics then govern how your bones and joints move when you walk. As an example, if your joints are very flexible, this can cause an abnormal amount of instability in your forefoot when you walk. Over time, this abnormal motion will cause the a bunion to develop by allowing your first metatarsal to "drift" towards the mid-line of your body.
If a foot bunion is developing, you may experience some of these symptoms. Bulge or bump on the outside of the base of your big toe. Swelling. Redness. Soreness. Thickening of the skin in that location. Corns or calluses. Limited movement of your big toe. Persistent or periodic pain. The pain you experience may be mild or severe. It may become increasingly difficult to walk in your normal shoes. The pressure on your other toes can cause your toenails to grow inward or your smaller toes to become bent.
Physical examination typically reveals a prominence on the inside (medial) aspect of the forefoot. This represents the bony prominence associated with the great toe joint ( the medial aspect of the first metatarsal head). The great toe is deviated to the outside (laterally) and often rotated slightly. This produces uncovering of the joint at the base of the big toe (first metatarsophalangeal joint subluxation). In mild and moderate bunions, this joint may be repositioned back to a neutral position (reduced) on physical examination. With increased deformity or arthritic changes in the first MTP joint, this joint cannot be fully reduced. Patients may also have a callus at the base of their second toe under their second metatarsal head in the sole of the forefoot. Bunions are often associated with a long second toe.
Non Surgical Treatment
Apply special pads and dressings to protect the bunion from shoe pressure. Inject steroid and local anesthetic around the bunion to reduce inflammation. This is especially useful if there is an associated bursitis. Recommend commercially available or custom made shoes. Prescribe functional orthotics to correct faulty foot function, and help prevent worsening of the deformity. Recommend bunion surgery to correct the deformity.
The type of surgical procedure performed depends upon the severity of the bunion, the individual?s age, general health, activity level, and the condition of the bones and connective tissue. Other factors may influence the choice of a procedure used. Mild bunion. For this type of surgery, the surgeon may remove the enlarged portion of bone and realign the muscles, tendons, and ligaments surrounding the joint. Moderate bunion. For a moderate bunion, the surgeon may cut the bone and shift it to its proper position. Whether or not the bone is cut depends on the severity and location of the deformity. In addition, the surrounding tendons and ligaments may need to be repositioned. Severe bunion. For a severe bunion, surgery may involve removing the enlarged portion of the bone, cutting and realigning the bone, and correcting the position of the tendons and ligaments. Arthritic bunion or big toe joint. If the joint is damaged beyond repair, as is commonly seen in arthritis, it may need to be reconstructed or replaced with an artificial joint. Joint replacement implants may be used in the reconstruction of the big toe joint.