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Bunions
 

Dr. Ian H. Beiser's Podiatry Page

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Dr. Beiser is a podiatrist serving patients in the Washington, DC, area

He is a partner in Foot and Ankle Specialists of the Mid-Atlantic, LLC,  a diverse group of foot and ankle specialists, dedicated to providing advanced and comprehensive foot and ankle care

1145 19th St., NW  Suite #203
Washington, DC 20036
(202) 833-9109

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Bunions (Hallux Abducto Valgus, Hallux Valgus, H.A.V.)

A bunion is an abnormal prominence located on the side of the foot, just behind the big toe. Hallux Abducto Valgus refers to a deformity associated with a bunion in which the big toe (Hallux) is angled excessively toward the 2nd toe. The Hallux Abductus Angle may be used to quantify the amount of Hallux Abducto Valgus deformity (see diagrams    ). Hallux Abducto Valgus and Bunions are usually associated with flat feet ( hyper-pronating feet/ pes planus). Excessive pronation (flattening of the foot) leads to instability of the  first metatarsal bone which drifts up and out towards the side of the foot. The Intermetatarsal Angle is used to quantify the amount of this drift to the side (see diagrams   ). The big toe drifts the opposite direction toward the 2nd toe. The bunion prominence is often caused by some enlargement of the head of the 1st metatarsal bone as well as the position of the 1st metatarsal bone as it protrudes from the side of the foot. Conservative measures such as wearing wide shoes and padding may help to provide some relief of symptoms but do nothing to remove the deformities. If conservative measures fail to  provide relief, surgical correction of the deformity should be considered. The most common surgeries  for bunions are done as outpatient procedures. The patient is usually able to walk the same day using a post-op shoe (although activities should be limited and the foot elevated as much as possible for at least the first three days.) There are many types of bunion surgery and post-operative limitations will vary depending on the severity of the condition and the procedures chosen.

              

Additional Material

Stages of Hallux Valgus and Bunion deformities

Hallux Abducto Valgus and their associated bunion deformities develop gradually over a period of time. It may not be until the more advanced stages that they become symptomatic. Wearing tight, pointy shoes alone does not usually cause bunions but may be an important factor, particularly with regard to how symptomatic they become. It has been shown that bunions are still found in certain cultures around the world where shoes are not worn. (However, in those places it is likely that the bunions do not cause significant symptoms). Probably the single most important factor leading to the development of bunions is excessive pronation or flattening of the foot. Excessive pronation may be caused by several conditions such as loose ligaments (laxity), a tight heel cord (equinus), limb length discrepancies (the longer leg usually pronates excessively and the short leg is usually high arched) , tendon abnormalities (rupture or improper insertion of the posterior tibial tendon), abnormal bone alignment (forefoot varus, metatarsus adductus, genu valgum, etc.), arthritic conditions (e.g. rheumatoid arthritis), fusions of bone during development (tarsal coalition) as well as others. The excessive pronation (hyperpronation) leads to instability of the 1st metatarsal bone which drifts up and out towards the side of the foot. The tendons that make the big toe go up and down (flexor and extensor tendons)  pull back on the big toe. Since the big toe is not aligned straight but rather angled toward the 2nd toe, when these tendons pull back on the big toe, it in turn pushes the 1st metatarsal bone further to the side, causing the bunion to appear larger. The side of the 1st metatarsal bone also becomes enlarged.   Thus, a bunion deformity is usually a combination of the abnormal position of the 1st metatarsal bone as well as an enlargement of its 'head'. In the past, many bunion surgeries consisted of simply removing a piece of the enlarged bone. This accounted for a large amount of recurrences and surgical failures. It is now know that in addition to removal of the enlarged bone,  the positional deformity of the 1st metatarsal and/or the 1st metatarsal-phalangeal joint ( joint between the fist metatarsal and the big toe) must be corrected, if they exist, to prevent recurrence of the condition.

Hallux Abducto Valgus and Bunion deformities develop gradually over a period of time. They can be loosely categorized as mild, moderate and severe. They can also be categorized as arthritic and non-arthritic. There are also dorsal bunions which are enlargements on the top of the fist metatarsal head rather than on the side of the foot. These may develop as a result of "jamming" of the 1st metatarsal-phalangeal joint and may be associated with an abnormally long 1st metatarsal or a 'square' rather than round 1st metatarsal head.

There a many different surgical procedures available for treatment of hallux valgus/ bunion surgery, ranging from the very simple to the highly technical. Thus, when you talk to acquaintances who tell you about their "bunionectomy", keep in mind that they are not referring to a single procedure called a 'Bunionectomy' but one of many procedures classified as bunionectomies. Some provide for the ability to walk and resume regular activities immediately while others may require a cast and crutches with no weightbearing for two months or longer. Several factors are considered in determining the appropriate surgical procedure. Examples of criteria considered are: 1. The 1st inter- metatarsal angle (I.M. angle), the angle between the 1st and the 2nd metatarsal,  2. The Proximal Articular Set Angle (P.A.S.A.), the angle between the cartilage that articulates with the big toe relative to the 1st metatarsal and 3. The Hallux Abductus Angle, the angle between the big toe and the 1st metatarsal. Other criteria include the amount of 1st metatarsal elevatus (how high the 1st metatarsal is raised off the ground), the range of 1st MTP joint motion, the amount of joint space narrowing, arthritis, osteoporosis,  and the presence of joint pain. The podiatric surgeon will also take into account the lifestyle of the patient (age, activity level, sports activities, etc.) to determine the appropriate procedure.

Stages of Bunion deformities

Mild

There is often a small bump (medial eminence of the 1st metatarsal head) and  limited angulations of the 1st metatarsal bone (1st metatarsal angle, I.M. angle) and the big toe (Hallux). The big toe may abut the 2nd toe.

 

Moderate

The big toe (Hallux) abuts the 2nd toe, the 1st metatarsal angle (I.M. angle) may range between 12 and 16 degrees. (These measurements may be less if the person has a metatarsus adductus or intoed foot). There may or may not be permanent adaptation of the cartilage to the big toe (increased P.A.S.A.). There is a moderate or large bump (medial eminence of the 1st metatarsal head). The big toe may simply abut the 2nd toe or may push it to the side.

             

 

Severe

The big toe may completely displace the 2nd toe. The 2nd toe may sit on top of the big toe or vice versa. There is a large bump. The 1st metatarsal angle (I.M. angle) is usually greater than 16 degrees. There is usually permanent adaptation of the cartilage to the big toe (increased P.A.S.A.).

   

 

Arthritic (Degenerative Joint Disease, DJD)

May encompass any of the above but also includes joint space narrowing (erosion of cartilage) and varying amounts of bony spurs around the 1st metatarsal-phalangeal joint. Milder cases may consist of slight limitation of motion and little pain. More severe cases may consist of a rigid joint and considerable pain.

Common Bunion Procedures

Simple bunionectomy (e.g. Silver Procedure)

This procedure does not address the imbalance at the 1st
Metatarsal-phalangeal joint and 1st metatarsal associated with most bunions so is not utilized as much as it once was. However, there are times when a simple bunionectomy (just removal of the bump) is indicated even in people with  severe bunions. An example would be a diabetic with an ulcer and/or infection stemming from the bunion. In this case, the infected or prominent bone must be removed but additional surgery would risk spreading the infection or could compromise the ability to heal. This procedure usually allows for immediate walking, usually with a surgical shoe. The surgical shoe is usually worn for about 1 month. After this time, most people are able to begin a gradual return to athletic shoe.


Dorsal Bunionectomy

The dorsal bunionectomy is a removal of bone at the top of the 1st metatarsal rather than the classic bunion at the side of the foot. This procedure usually allows for immediate walking, usually with a surgical shoe. The surgical shoe is usually worn for about 1 month. After this time, most people are able to begin a gradual return to athletic shoe.


Capsule Tendon Balance Procedure (e.g. Modified McBride Procedure)

This procedure involves removal of the bump (enlarged portion of 1st metatarsal head) as well as rebalancing of the big toe joint by releasing the tight tendons on the lateral side (side nearest to the 2nd toe) and tightening the joint capsule on the medial side (side where the bump was removed) and sometimes removing one of the sesamoid bones. This procedure is utilized when there is a positional Hallux Valgus (in other words, the big toe is drifted over  toward the 2nd toe but there are no significant bone or structural deformities other than the bunion bump. Sometimes this procedure may also be used in conjunction with other procedures. This procedure usually allows for immediate walking, usually with a surgical shoe. The surgical shoe is usually worn for about 1 month. After this time, most people are able to begin a gradual return to athletic shoe.


Wedge Osteotomy of the Hallux Proximal phalanx (Akin Procedure)

This procedure involves removal of a pie-shaped wedge of bone from the base of the big toe to straighten the toe when that is the area of maximal deformity. The deformity is more commonly found in other locations so this procedure is not done as often as the others. Sometimes it may be used in conjunction with one of the other procedures. This procedure usually allows for immediate walking, usually with a surgical shoe. The surgical shoe is usually worn for about 1 month. After this time, most people are able to begin a gradual return to athletic shoe.

 

First Metatarsal Head Osteotomies
    Austin Procedure (Chevron procedure) and its many variations

This is probably the most commonly performed bunionectomy procedure today. It is used to correct moderate hallux abducto valgus deformities. A   "V" -shaped cut is made in the 1st metatarsal head from side to side after the bump has been removed. The 1st metatarsal head is then shifted toward the 2nd metatarsal to reduce the 1st intermetatarsal angle. It is often held in place with one of several different devices such as a metal pin (K-wire), a metal screw or an absorbable pin or screw. This procedure usually allows for immediate walking, usually with a surgical shoe. The surgical shoe is usually worn for about 1 month. After this time, most people are able to begin a gradual return to athletic shoe.

Diagram of Surgical Procedure: 

X-ray Before:          X-ray After: 


Reverdin Procedure or one of its many variations

Also performed at the 1st metatarsal head, this procedure involves removing a wedge of bone rather than making a straight cut through the bone.This procedure is used when the major deformity is the angulation of the cartilage that forms the joint with the big toe (P.A.S.A. deformity). This procedure usually allows for immediate walking, usually with a surgical shoe. The surgical shoe is usually worn for about 1 month. After this time, most people are able to begin a gradual return to athletic shoe.


Base Wedge Osteotomy

This procedure is utilized for bunions associated with a very large 1st intermetatarsal angle. As its name implies, a wedge of bone is removed from the base of the 1st metatarsal bone. A hinge remains between the front and back portion of the bone. As the front portion is swung along the hinge to close the gap made by the wedge, the I.M. angle is reduced and the 1st metatarsal becomes straight and more parallel to the 2nd metatarsal. The bone is then held together during the healing process by special screws or metal pins. The base wedge procedure is  more unstable than most of the other procedures and requires a cast and no weightbearing for a minimum of 8 weeks. After that, partial weightbearing is often allowed as a transition to full weightbearing.

Diagram of surgical procedure: 

 

Lapidus Procedure

This procedure is similar to the Base Wedge Osteotomy procedure but it is performed within the 1st-metatarsal-cuneiform joint (1st MCJ). The 1st MCJ is fused in the process. This procedure is performed in similar instances as the Base Wedge Procedure,( a very large I.M. angle) particularly with a very flexible or hypermobile 1st MCJ. The fusion is held together with special screws or pins. Like the base wedge procedure, the Lapidus procedure is  more unstable than most of the other procedures and requires a cast and no weightbearing for a minimum of 8 weeks. After that, partial weightbearing is often allowed as a transition to full weightbearing.


1st Metatarsal-Phalangeal Joint Arthroplasty (Keller Bunionectomy)

This is a procedure used for certain cases of severe arthritis or limited motion at the big toe joint. The cartilage and part of the bone that makes up the base of the big toe is removed. This allows for greater motion at that joint. This procedure may also be used occasionally on older patients whose bone may not be suitable for one of the 'osteotomy' procedures above. This procedure usually allows for immediate walking, usually with a surgical shoe. The surgical shoe is usually worn for about 1 month. After this time, most people are able to begin a gradual return to athletic shoe.

1st Metatarsal-Phalangeal Joint Fusion (Arthrodesis)

This procedure is used in similar situations to the Arthroplasty/ Keller procedure where there is significant arthritis or limitation of motion. The trade-off is complete lack of motion at the 1st Metatarsal-Phalangeal Joint but   increased stability. In the geriatric population where this procedure is most typically performed, most people are able to function quite well in spite of the lack of motion at the 1st Metatarsal-Phalangeal Joint. The 1st MPJ fusion procedure often requires casting and a period of non-weightbearing but  it is a more stable than the Base Wedge and Lapidus procedures and as such does not often require as much time non- weightbearing as the Base Wedge and Lapidus.

 

Cheilectomy

This is a procedure which may be utilized in earlier stages of an arthritic joint in which there are painful bone spurs. The bony irregularities are shaved off and the cartilage may also be remodeled. This procedure usually allows for immediate walking, usually with a surgical shoe. The surgical shoe is usually worn for about 3 weeks. After this time, most people are able to begin a gradual return to athletic shoe.


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Information on Absorbable (dissolving) pins used in bunion surgery

 

 

Ian H. Beiser, D.P.M., F.A.C.F.A.S, F.A.S.P.S.

Foot and Ankle Specialists of the Mid-Atlantic, LLC
1145 19th St., NW  Suite #203
Washington, DC 20036
(202) 833-9109

 
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