Amniotic Band Syndrome

Amniotic band syndrome (ABS) is an uncommon, congenital fetal abnormality with multiple disfiguring and disabling manifestations. A wide spectrum of clinical deformities are encountered and range from simple ring constrictions to major head, face and internal organ defects. Lower extremity limb malformations are extremely common and consist of asymmetric digital ring constrictions, distal atrophy, congenital intrauterine amputations, and clubfoot. Although debated, early amnion rupture with subsequent entanglement of fetal parts (mostly limbs and appendages) by amniotic strands is the primary theory of pathogenesis.

Amniotic band syndrome is associated with an excessive number of synonyms and acronyms such as congenital constriction band syndrome, Streeter's dysplasia, Simonart's bands, amniotic band disruption complex, congenital annular defects, congenital ring constrictions, ADAM (Amniotic Deformity, Adhesion, Mutilations) complex, TEARS (The Early Amnion Rupture Spectrum) of defects, and fetal disruption complex. The overabundance of synonyms/acronyms used to describe the congenital malformations in ABS attest partly to the confusion surrounding its etiology.

Current literature supports the theory that early amniotic rupture leads to the formation of fibrous strands that entangle limbs and appendages. This sequence affects the development of the embryo and leads to the findings seen in ABS. Therefore, nearly all cases reach their final form before birth with tissue damage healing before birth. The nature and severity of deformities that result appears to be related to the timing and initiating event of amniotic rupture.

Clinical Findings

Amniotic band syndrome is a complex collection of asymmetric congenital anomalies, in which no two cases are exactly alike. However, several characteristic features are relatively consistent findings. Distal ring constrictions and intrauterine amputations, are the most common findings of ABS and are typically seen in the distal aspect of extremities. Multiple extremity involvement is usually expressed with an average of three extremity parts affected.

Incidence

Amniotic band syndrome is not a rare anomaly as first described more than a century and a half ago and appears to be rising. Once believed to have an incidence of 1:100,000, recent literature supports the incidence today as 1:1200 to 1:1500 births. No distinct sex predilection has been determined. Nearly sixty percent of the cases documented have some sort of abnormal gestation history. Prenatal risk factors associated with amniotic band syndrome include prematurity (<37 weeks), low birth weight (<2500 g), maternal illness (during pregnancy), maternal drug exposure and maternal hemorrhage/trauma. Attempted abortion in the first trimester is also a highly associated finding.

Family history seldom reveals any direct inheritance pattern, since the syndrome occurs in no particular association with know genetic or chromosomal disorders. Karotypes are virtually always normal, and the syndrome is almost always sporadic in nature. Infants of young, black women who have been pregnant more than once (<20 years, more than one pregnancy) show the highest prevalence. incidences of malformations seen in the hand are two times as common as accompanied foot deformities.

Pathogenesis

Many theories concerning the pathogenesis of ABS have been proposed and debated. Furthermore, no single pathogenic conclusion has been determined to reconcile the diverse findings seen in ABS. However, much of the controversy still centers around a fundamental question: Is ABS a primary event of an intrinsic (endogenous) fetal anomaly or a condition extrinsic (exogenous) to the fetus that is secondarily involved?

Although a number of experimental models have been developed to reproduce its occurrence, no unified theory exists. It is easy to believe the amniotic band theory proposed when the majority of pregnancies (60%) demonstrate an abnormal pregnancy history. However, this does not explain the remaining 40% occurrence of ABS in mothers with no abnormal prenatal history. One may never reconcile the differences in findings seen in ABS into a single pathogenic scheme. Perhaps, ABS is composed of a combination of causes as stated above.

Characteristic Features

Amniotic band syndrome is a poorly defined clinical entity, owing partly to its debated causes and large number of different names. However, it is routinely characterized by distinct fetal malformations, which should make its diagnosis unmistakable.

The most common triad of clinical manifestations include congenital distal ring constrictions, intrauterine amputations, and acrosyndactyly. These anomalies appear most frequently in the distal aspect of extremities without other organ involvement. It has been found that ABS is the most common cause of a terminal congenital malformation of a limb.

Additional abnormalities encountered routinely with ABS include webbing of the fingers or toes, progressive lymphedema (swelling), clubfoot, stunted growth of the small bones in the fingers and toes and limb length discrepancy. Less common findings include: pseudarthrosis, metatarsus adductus, peripheral nerve palsy, dystrophic nails, postnatal gangrene, cleft lip and palate, skin-tube pedicles, dislocated hip visceral body wall malformations and eccentric craniofacial synostosis defects. Owing to the fact that no two cases are exactly alike, only some of these above-mentioned defects are present in each individual case. Other congenital brain abnormalities, cardiac malformations, short statue, spina bifida, and added miscellaneous conditions reported in the literature probably represent coincidental findings. Fetal death associated with amniotic band strangulation of the umbilical cord has also been reported.

Amniotic bands are more likely to constrict, entangle or amputate fingers or toes that protrude the furthest. In the hand, digital amputations most commonly involve the index, middle, and ring fingers, whereas in the foot, amputations of the big toe are most often noted. Congenital band indentations are usually at multiple levels with or without distal lymphedema (swelling). However, these fibrous band indentations are noted encircling the fingers or toes of the newborn child most frequently. Bands are of variable width and depth, ranging from shallow indentations of the skin and subcutaneous tissue to deep grooves extending down to deep fascia or bone. Proximal bands occur more commonly in the lower extremity and have been associated with neural compression. Osseous abnormalities occurring at or below band indentation such a bony fusion, angular deformities, and discontinuity have infrequently been reported.

If ring constriction is severe, the veins, arteries, lymphatics, and nerves may be comprised. However, vascular insufficiency is seldom symptomatic. Neurological impairment is usually attributed to axontmesis or neurotmesis. This may be caused by direct pressure from the constriction band or attributable in compartment syndrome distal to the band in infants with rapidly progressive swelling.

Distal digits are typically malformed, owing to phalageal hypoplasia or terminal amputation. Acrosyndactyly (fenestrated syndactyly) is frequently associated with distal amputation. This type of syndactyly involves the binding of adjacent digits in a “lassoed” appearance. If acrosyndactyly is present, it invariably is associated with a proximal interdigital sinus or cleft that communicates from dorsal to plantar. The cutaneious syndactyly seen usually does not involve underlying bony fusion.

A strong relationship between ABS and clubfoot exists. A 31.5% incidence of associated clubfoot deformity and ABS can be correlated with 20% occurring bilaterally. In the majority of cases, the clubfoot deformity present is inordinately rigid and unresponsive to conservative modalities.

Limb length discrepancy has also been noted in legs encircled by amniotic bands with an average functional deficit of greater than 2.5 cm. This often results in biomechanical abnormalities and altered gait patterns.

Diagnosis

Ultrasonographic analysis allows for the detection of ABS prenatally by visualization of amniotic sheets or bands attached to the fetus. In the first trimester, it is extremely difficult to detect ABS, especially if the bands are limited to the extremities. However, in the second and third trimester of pregnancy, it is relatively easy to detect the major anomalies of ABS by its characteristic features and restrictions of motion. When characteristic asymmetric fetal anomalies are observed ultrasonographically, regardless of the presence or absence of fibrous membranes, ABS should be considered.

Although visualization of amniotic bands on ultrasonography is helpful in confirming ABS, it is not in itself a diagnostic feature of the ABS. Recently, amniotic sheets or bands have been described as aberrant sheets of tissue, often amnion and chorion, having a free edge within the amniotic fluid. The free edge does not attach to the fetus and have been labeled “innocent amniotic sheet”. These sheets do not restrict fetal motion nor cause any fetal abnormalities.

Additionally, elevated maternal serum alpha-fetoprotein (MASFP) has been associated with ABS. However, elevated MSAFP is not diagnostic for ABS, since it is also elevated in neural tube defects, placental chorioangioma, and congenital nephrosis. MSAFP is now a standard screening test recommended for all pregnancies, though rarely elevated.

Treatment

Several treatment options are available for the lower extremity manifestations of ABS. Shallow grooves or bands require no operative treatment, unless they interfere with circulation or lymphatic drainage. Deep constriction bands often present with swelling distal to the band, extreme pain, and diminished circulation and must be surgically released immediately to prevent risk of gangrene or auto-amputation. Surgical excision of the fibrous band and any necrotic tissue with circumferential Z-plasty or W-plasty are the procedures most commonly employed. Removal of the constriction band may be accomplished in a one or two stage release, usually beginning at three months of age. Early surgical intervention is necessary to prevent progressive lymphedema. Patients treated late in the course of the syndrome often heal very slowly with secondary eczematous skin changes to distal parts.

When deemed necessary, subcutaneous fat and fascial flaps are advanced into the defect to prevent reoccurrence of the deformity. If edema persists after correction of the band, excision of the edematous area (debulking) may be necessary, with direct closure or conversion of the overlying skin to thick, free partial thickness skin grafts. Gross motor and sensory deficits distal to the bands resulting in neuropathy with secondary ulceration and osteomyelitis (bone infection) are best treated with amputation and fitting of a prosthesis. It is fairly uncommon that the underlying bones to be affected, however, if they are then cresentic osteotomies may be indicated.

Desyndactylizations may also need to be performed in conjunction with skin grafting of hypoplastic bones. Due to the high incidence of associated rigid clubfoot deformity, aggressive surgical correction is often required. Limb length discrepancies greater than 6 cm may require leg-lengthening procedures.

Overall, the goal of pedal care is to create a functional foot and to minimize additional problems as the child grows. Parental counseling is recommended to convey there is no known associated risk for subsequent pregnancies.

Conclusion

Amniotic band syndrome is an uncommon fetal malformation with increasing prevalence. It is a constellation of congenital anomalies that lacks a precise definition and satisfactory pathogenic explanation. Multiple asymmetrical limb, craniofacial, visceral, and body wall defects are commonplace. Although a myriad of fetal deformities can ensue, manifestations in the foot such as distal ring constrictions, intrauterine pedal amputations, acrosyndactyly, and clubfoot are encountered routinely. With the aid of ultrasonography, a prenatal diagnosis of ABS can be made by serial observations demonstrating restriction of fetal movement. Appropriate surgical intervention can eliminate potential limp threatening constrictions and provide a remarkably improved quality of life for these patients.

Common Digital Deformities in Children

Deformities of the toes are common in the pediatric population. Generally they are congenital in nature with both or one of the parents having the same or similar condition. Many of these deformities are present at birth and can become worse with time. Rarely do children outgrow these deformities although rare instances of spontaneous resolution of some deformities have been reported.

Malformation of the toes in infancy and early childhood are rarely symptomatic. The complaints of parents are more cosmetic in nature. However, as the child matures these deformities progress from a flexible deformity to a rigid deformity and become progressively symptomatic. Many of these deformities are unresponsive to conservative treatment. Common digital deformities are underlapping toes, overlapping toes, flexed or contracted toes and mallet toes. Quite often a prolonged course of digital splitting and exercises may be recommended but generally with minimal gain. As the deformity becomes more rigid surgery will most likely be required if correction of the deformity is the goal.

Underlapping Toes

Description

Underlapping toes are commonly seen in the adult and pediatric population. The toes most often involved are the fourth and fifth toes. A special form of underlaping toes is called clinodactyly or congenital curly toes. Clinodactyly is fairly common and follows a familial pattern. One or more toes may be involved with toes three, four, and five of both feet being most commonly affected.

The exact cause of the deformity is unclear. A possible etiology is an imbalance in muscle strength of the small muscles of the foot. This is aggravated by a subtle abnormality in the orientation on the joints in the foot just below the ankle joint called the subtalar joint. This results in an abnormal pull of the ligaments in the toes causing them to curl. With weight bearing the deformity is increased and a folding or curling of the toes results in the formation of callus on the outside margin of the end of the toe. Tight fitting shoes can aggravate the condition.

Treatment

The age of the patient, degree of the deformity and symptoms determine treatment. If symptoms are minimal, a wait and see approach is often the best bet. When treatment is indicated the degree of deformity determines the level of correction. When the deformity is flexible in nature a simple release of the tendon in the bottom of the toe will allow for straightening of the toe. If the deformity is rigid in nature then removal of a small portion of the bone in the toe may be necessary. Both of these procedures are common in the adult patient for the correction of hammertoe deformity. If skin contracture is present a derotational skin plasy may be required.

Overlapping Toes - Overlapping Fifth Toe

Description

This deformity is characterized by one toe lying on top of an adjacent toe. The most common toe involved is the fifth toe. When one of the central toes is involved the second toe is most commonly affected. The etiology of the condition is not well understood. It is though that it may be caused by the position of the fetus in the womb during development. The condition my run in families so there may be a hereditary component to the deformity.

Treatment

Effective conservative treatment depends upon how early the diagnosis is made. In infancy, passive stretching and adhesive tapping is most commonly used. This may require 6 to 12 weeks to accomplish and reoccurrence is not uncommon. Rarely will the deformity correct itself. As the individual matures the deformity becomes fixed. When surgical correction is warranted a skin plasty is required to release the contracture of the skin associated with the deformity. Additionally a tendon release and a release of the soft tissues about the joint at the base of the fifth toe may be required. In severe cases the toe may require the placement of a pin to hold the toe in a straightened position. The pin, which exits the tip of the toe, may be left in place for up to three weeks. During this period of time the patient must curtail their activities significantly and wear either a post-operative type shoe or a removable cast. Excessive movement at the surgical site can result in a less than desirable result. The pin can be easily removed in the doctor's office with minimal discomfort. Following removal of the pin splinting of the toe may be required for an additional two to three weeks.

Hammertoes and Mallet Toes

Description

Another common digital deformity is contracture of the toes in the formation of hammertoes and mallet toes. Hammertoes are described in depth in another article. Mallet toes are a result of contracture of the last joint in the toe. In the pediatric population it is often flexible and not painful. Over time the deformity becomes rigid and a callus may form on the skin overlying the joint at the end of the toe. Additionally the toenail may become thickened and deformed form the repetitive jamming of the toe while walking. The deformity usually involves one or two toes, with the second toe most commonly affected. Mallet toes have several etiologies. Longer toes that are forced against a short toe box in the shoe will, over time, develop a contracture of the last joint in the toe causing a mallet toe.

Treatment

Conservative treatment consists of padding and strapping the toes into a corrected position. This treatment may alleviate the symptoms but will not correct the deformity. Diabetic patients often develop ulcerations on the ends of their toes secondary to mallet toe deformity and the pressure that results from the toe jamming into the shoe. When standing, the toe will demonstrate a contracture, with the tip of the toe facing downward into the floor. If the deformity is flexible a simple release of the tendon in the bottom of the toe will allow straightening of the toe. Following the procedure the patient must avoid shoes that cause jamming of the toe or the deformity can reoccur. When the deformity is rigid surgical correction requires the removal of a small section of bone in the last joint of the toe. On occasion fusion of the last two bones in the toe may be necessary. This requires removing the cartilage from the last joint in the toe and pinning the bones together. When the bone heals it forms a single bone and the toe remains in a straightened position. Healing time is dependent upon the procedure selected. If a tendon release is performed the patient my return to a roomy shoe within a week. If the toe is straightened by removing a section of the bone in the toe it make ten days to three weeks for a patient to return to normal shoes. If a fusion is performed to straighten the toe, the patient may not return to normal shoes for 6 to 8 weeks. Time off from work will depend upon the type of shoe gear that must be worn and the level of activity necessary to perform the job. A minimum of three to four days off from work is generally recommended and longer if the job responsibilities can not be modified to accommodate the normal healing time for the surgery.

Curled Toes

Deformities of the toes are common in the pediatric population. Generally they are congenital in nature with both or one of the parents having the same or similar condition. Many of these deformities are present at birth and can become worse with time. Rarely do children outgrow these deformities although rare instances of spontaneous resolution of some deformities have been reported.

Malformation of the toes in infancy and early childhood are rarely symptomatic. The complaints of parents are more cosmetic in nature. However, as the child matures these deformities progress from a flexible deformity to a rigid deformity and become progressively symptomatic. Many of these deformities are unresponsive to conservative treatment. Common digital deformities are underlapping toes, overlapping toes, flexed or contracted toes and mallet toes. Quite often a prolonged course of digital splitting and exercises may be recommended but generally with minimal gain. As the deformity becomes more rigid surgery will most likely be required if correction of the deformity is the goal.

Underlapping Toes

Description

Underlapping toes are commonly seen in the adult and pediatric population. The toes most often involved are the fourth and fifth toes. A special form of underlaping toes is called clinodactyly or congenital curly toes. Clinodactyly is fairly common and follows a familial pattern. One or more toes may be involved with toes three, four, and five of both feet being most commonly affected.

The exact cause of the deformity is unclear. A possible etiology is an imbalance in muscle strength of the small muscles of the foot. This is aggravated by a subtle abnormality in the orientation on the joints in the foot just below the ankle joint called the subtalar joint. This results in an abnormal pull of the ligaments in the toes causing them to curl. With weight bearing the deformity is increased and a folding or curling of the toes results in the formation of callus on the outside margin of the end of the toe. Tight fitting shoes can aggravate the condition.

Treatment

The age of the patient, degree of the deformity and symptoms determine treatment. If symptoms are minimal, a wait and see approach is often the best bet. When treatment is indicated the degree of deformity determines the level of correction. When the deformity is flexible in nature a simple release of the tendon in the bottom of the toe will allow for straightening of the toe. If the deformity is rigid in nature then removal of a small portion of the bone in the toe may be necessary. Both of these procedures are common in the adult patient for the correction of hammertoe deformity. If skin contracture is present a derotational skin plasy may be required.

Overlapping Toes - Overlapping Fifth Toe

Description

This deformity is characterized by one toe lying on top of an adjacent toe. The most common toe involved is the fifth toe. When one of the central toes is involved the second toe is most commonly affected. The etiology of the condition is not well understood. It is though that it may be caused by the position of the fetus in the womb during development. The condition my run in families so there may be a hereditary component to the deformity.

Treatment

Effective conservative treatment depends upon how early the diagnosis is made. In infancy, passive stretching and adhesive tapping is most commonly used. This may require 6 to 12 weeks to accomplish and reoccurrence is not uncommon. Rarely will the deformity correct itself. As the individual matures the deformity becomes fixed. When surgical correction is warranted a skin plasty is required to release the contracture of the skin associated with the deformity. Additionally a tendon release and a release of the soft tissues about the joint at the base of the fifth toe may be required. In severe cases the toe may require the placement of a pin to hold the toe in a straightened position. The pin, which exits the tip of the toe, may be left in place for up to three weeks. During this period of time the patient must curtail their activities significantly and wear either a post-operative type shoe or a removable cast. Excessive movement at the surgical site can result in a less than desirable result. The pin can be easily removed in the doctor's office with minimal discomfort. Following removal of the pin splinting of the toe may be required for an additional two to three weeks.

Hammertoes and Mallet Toes

Description

Another common digital deformity is contracture of the toes in the formation of hammertoes and mallet toes. Hammertoes are described in depth in another article. Mallet toes are a result of contracture of the last joint in the toe. In the pediatric population it is often flexible and not painful. Over time the deformity becomes rigid and a callus may form on the skin overlying the joint at the end of the toe. Additionally the toenail may become thickened and deformed form the repetitive jamming of the toe while walking. The deformity usually involves one or two toes, with the second toe most commonly affected. Mallet toes have several etiologies. Longer toes that are forced against a short toe box in the shoe will, over time, develop a contracture of the last joint in the toe causing a mallet toe.

Treatment

Conservative treatment consists of padding and strapping the toes into a corrected position. This treatment may alleviate the symptoms but will not correct the deformity. Diabetic patients often develop ulcerations on the ends of their toes secondary to mallet toe deformity and the pressure that results from the toe jamming into the shoe. When standing, the toe will demonstrate a contracture, with the tip of the toe facing downward into the floor. If the deformity is flexible a simple release of the tendon in the bottom of the toe will allow straightening of the toe. Following the procedure the patient must avoid shoes that cause jamming of the toe or the deformity can reoccur. When the deformity is rigid surgical correction requires the removal of a small section of bone in the last joint of the toe. On occasion fusion of the last two bones in the toe may be necessary. This requires removing the cartilage from the last joint in the toe and pinning the bones together. When the bone heals it forms a single bone and the toe remains in a straightened position. Healing time is dependent upon the procedure selected. If a tendon release is performed the patient my return to a roomy shoe within a week. If the toe is straightened by removing a section of the bone in the toe it make ten days to three weeks for a patient to return to normal shoes. If a fusion is performed to straighten the toe, the patient may not return to normal shoes for 6 to 8 weeks. Time off from work will depend upon the type of shoe gear that must be worn and the level of activity necessary to perform the job. A minimum of three to four days off from work is generally recommended and longer if the job responsibilities can not be modified to accommodate the normal healing time for the surgery.

Kohler's Disease

Kohler's Disease is a spontaneous loss of blood supply to a bone in the foot called the Navicular bone. Dr. Kohler described it in 1908. The spontaneous loss of blood supply to a bone is called osteochondrosis. In later years Dr. Kohler was also associated with another osteochondrosis of the foot known as Freiberg's disease. Some texts refer to this condition as Kohler's II.

Clinical features and Treatment

Clinically, the presentation of Kohler's disease may be an incidental x-ray finding. Often, however, localized pain or a painful gait is noted. Occasionally mild swelling is seen. It is seen most commonly in males and most cases only affect one foot. Biopsy of the bone to make the diagnosis is not necessary.

Complete recovery is almost always the rule; therefore, treatment efforts should be conservative. Cast immobilization provides satisfactory results. Reduced activities and foot orthotics (inserts for the shoes) have also proved effective. Most cases respond within 8 months. Follow-up studies after 30 years have shown no residual degenerative changes in spite of severe fragmentation and flattening of the navicular bone. It is interesting to note that Kohler's disease has been reported to be associated with "Tarsal Coalition" in this area. So it is important that proper follow-up be done.

This article was adapted from the text book Foot and Ankle Disorders in Children edited by Dr. Steven DeValentine.

Metatarsus Adductus

Metatarsus adductus is a congenital deformity of the foot where there is increased curvature of the forefoot. This gives the foot the appearance of a "C" shape. This deviation of the metatarsals or visual effect of in-toeing is a deformity that occurs at the midfoot of the foot. The diagnosis of metatarsus adduction is relatively straightforward and is predominantly a clinical diagnosis. The exact cause of metatarsus adductus is not fully understood but is considered to be caused by intrauterine position and pressures. There may also be a genetic component to the deformity.

Diagnosis

The diagnosis of metatarsus adductus is made by physical examination and has certain characteristics:

• the foot has an inward position as compared to the lower leg
• the foot has a concave border medially and a convex border laterally
• the metatarsus adductus foot may appear with a high arch
• there is usually a separation of the big toe from the lesser toes

Treatment

Non Operative Treatment

Most children with the metatarsus adductus deformity can be treated with conservative measures. Mild flexible cases can be treated with stretching and strengthening modalities, braces, orthoses, or straight last or reverse last shoe gear. In some cases serial casting may be necessary. This consists of applying plaster to the foot reducing the deformity. The cast is changed every 7 to 14 days. Casting is recommended until the deformity is reduced and then for half the amount of time again. In other words if it takes 6 weeks of casting to reduce the deformity then the infant should be cast for an additional three weeks. In those children who require casting those treated prior to the age of ambulation have more favorable results, but that doesn't mean that those with the deformity shouldn't be treated after ambulation begins. In cases where the deformity is resistant to conservative treatment or the deformity is rigid, surgical treatment may be considered.

Operative

Operative treatment is reserved for deformities that have been neglected or have not responded to non-operative treatments. If surgery is required there are several different procedures depending on the age of the patient and the magnitude of the deformity. In less severe cases, soft tissue releases or tendon transfers can correct the deformity. While in more severe cases bony cuts and repositioning is the best treatment option. Following any type of surgical correction braces, orthoses or orthopedic shoes may be required.

Overlapping Toes

Deformities of the toes are common in the pediatric population. Generally they are congenital in nature with both or one of the parents having the same or similar condition. Many of these deformities are present at birth and can become worse with time. Rarely do children outgrow these deformities although rare instances of spontaneous resolution of some deformities have been reported.

Malformation of the toes in infancy and early childhood are rarely symptomatic. The complaints of parents are more cosmetic in nature. However, as the child matures these deformities progress from a flexible deformity to a rigid deformity and become progressively symptomatic. Many of these deformities are unresponsive to conservative treatment. Common digital deformities are underlapping toes, overlapping toes, flexed or contracted toes and mallet toes. Quite often a prolonged course of digital splitting and exercises may be recommended but generally with minimal gain. As the deformity becomes more rigid surgery will most likely be required if correction of the deformity is the goal.

Underlapping Toes

Description

Underlapping toes are commonly seen in the adult and pediatric population. The toes most often involved are the fourth and fifth toes. A special form of underlaping toes is called clinodactyly or congenital curly toes. Clinodactyly is fairly common and follows a familial pattern. One or more toes may be involved with toes three, four, and five of both feet being most commonly affected.

The exact cause of the deformity is unclear. A possible etiology is an imbalance in muscle strength of the small muscles of the foot. This is aggravated by a subtle abnormality in the orientation on the joints in the foot just below the ankle joint called the subtalar joint. This results in an abnormal pull of the ligaments in the toes causing them to curl. With weight bearing the deformity is increased and a folding or curling of the toes results in the formation of callus on the outside margin of the end of the toe. Tight fitting shoes can aggravate the condition.

Treatment

The age of the patient, degree of the deformity and symptoms determine treatment. If symptoms are minimal, a wait and see approach is often the best bet. When treatment is indicated the degree of deformity determines the level of correction. When the deformity is flexible in nature a simple release of the tendon in the bottom of the toe will allow for straightening of the toe. If the deformity is rigid in nature then removal of a small portion of the bone in the toe may be necessary. Both of these procedures are common in the adult patient for the correction of hammertoe deformity. If skin contracture is present a derotational skin plasy may be required.

Overlapping Toes - Overlapping Fifth Toe

Description

This deformity is characterized by one toe lying on top of an adjacent toe. The most common toe involved is the fifth toe. When one of the central toes is involved the second toe is most commonly affected. The etiology of the condition is not well understood. It is though that it may be caused by the position of the fetus in the womb during development. The condition my run in families so there may be a hereditary component to the deformity.

Treatment

Effective conservative treatment depends upon how early the diagnosis is made. In infancy, passive stretching and adhesive tapping is most commonly used. This may require 6 to 12 weeks to accomplish and reoccurrence is not uncommon. Rarely will the deformity correct itself. As the individual matures the deformity becomes fixed. When surgical correction is warranted a skin plasty is required to release the contracture of the skin associated with the deformity. Additionally a tendon release and a release of the soft tissues about the joint at the base of the fifth toe may be required. In severe cases the toe may require the placement of a pin to hold the toe in a straightened position. The pin, which exits the tip of the toe, may be left in place for up to three weeks. During this period of time the patient must curtail their activities significantly and wear either a post-operative type shoe or a removable cast. Excessive movement at the surgical site can result in a less than desirable result. The pin can be easily removed in the doctor's office with minimal discomfort. Following removal of the pin splinting of the toe may be required for an additional two to three weeks.

Hammertoes and Mallet Toes

Description

Another common digital deformity is contracture of the toes in the formation of hammertoes and mallet toes. Hammertoes are described in depth in another article. Mallet toes are a result of contracture of the last joint in the toe. In the pediatric population it is often flexible and not painful. Over time the deformity becomes rigid and a callus may form on the skin overlying the joint at the end of the toe. Additionally the toenail may become thickened and deformed form the repetitive jamming of the toe while walking. The deformity usually involves one or two toes, with the second toe most commonly affected. Mallet toes have several etiologies. Longer toes that are forced against a short toe box in the shoe will, over time, develop a contracture of the last joint in the toe causing a mallet toe.

Treatment

Conservative treatment consists of padding and strapping the toes into a corrected position. This treatment may alleviate the symptoms but will not correct the deformity. Diabetic patients often develop ulcerations on the ends of their toes secondary to mallet toe deformity and the pressure that results from the toe jamming into the shoe. When standing, the toe will demonstrate a contracture, with the tip of the toe facing downward into the floor. If the deformity is flexible a simple release of the tendon in the bottom of the toe will allow straightening of the toe. Following the procedure the patient must avoid shoes that cause jamming of the toe or the deformity can reoccur. When the deformity is rigid surgical correction requires the removal of a small section of bone in the last joint of the toe. On occasion fusion of the last two bones in the toe may be necessary. This requires removing the cartilage from the last joint in the toe and pinning the bones together. When the bone heals it forms a single bone and the toe remains in a straightened position. Healing time is dependent upon the procedure selected. If a tendon release is performed the patient my return to a roomy shoe within a week. If the toe is straightened by removing a section of the bone in the toe it make ten days to three weeks for a patient to return to normal shoes. If a fusion is performed to straighten the toe, the patient may not return to normal shoes for 6 to 8 weeks. Time off from work will depend upon the type of shoe gear that must be worn and the level of activity necessary to perform the job. A minimum of three to four days off from work is generally recommended and longer if the job responsibilities can not be modified to accommodate the normal healing time for the surgery.

Pediatric Flatfeet

A flatfoot deformity is where the arch on the inside border of the foot is more flat than normal. Flatfoot deformities can occur in all age groups, but appear most commonly in children. Some of these children grow up into adults who have feet with normal arches, but many of these children have pain related to their flatfoot deformity throughout their lives. It is very important that children with flatfoot deformity be evaluated by a podiatrist to determine if they need treatment to prevent future pain or deformity in their feet.

When the young child starts to first walk at about the age of 9-15 months of age, the foot has a fat or chubby appearance where there is a less bony architecture apparent in the foot. At this point in the development of the foot, it is very difficult to evaluate whether the child will have future problems with a flatfoot deformity.

At the ages of two and three, the child's foot starts to show more of its characteristic shape since the foot is less fat and the bones are more prominent. If the child has a flatfoot deformity at the ages of two to three, then it is wise to have the foot examined by a foot specialist such as a podiatrist. The reason that it is important to have the feet examined at this age is because the young foot is still largely made of cartilage, with less bone than would be present in the adult foot. Since cartilage is relatively soft, the abnormal forces caused by a flatfoot deformity may cause permanent structural alterations to the bones and joints of the foot that will persist into adulthood.

The flatfoot deformity in children causes a number of changes to the structure of the foot which is easily recognizable by the trained podiatrist. Flatfoot deformity causes the inside arch to be flattened, causes the heel bone to be turned outward, and causes the inside aspect of the foot to appear more bowed outward than normal. Most cases of flatfoot deformity in children are also associated with excessive flexibility in the joints of the foot which is commonly caused by ligamentous laxity.

Since the flatfoot deformity causes some instability of the foot during gait, children with flatfoot deformity may have complaints in the foot such as arch, heel, or ankle pain which is generally associated with increased standing, walking, or running activities. However, since the excessive rolling inward of the arches of the foot also make the leg and knee more turned inwards, children with flatfeet may also complain of pain in the low back, hip, knee, or leg due to the abnormal mechanics of the foot which is created by the flatfoot deformity.

Diagnosis

As mentioned above, the pediatric flatfoot deformity can be diagnosed at a very early age, but is unlikely to be properly diagnosed unless the doctor is a foot specialist, like a podiatrist, and is familiar with the intricacies of the structure and biomechanics of the foot. After speaking with the parent and child, the podiatrist will examine the foot both while the child is not bearing weight but also while the child is standing, walking or running. Often, the family history is also taken since the foot should be examined closely if the child has a close relative who had a painful flatfoot deformity as a child or adult.

During the examination of the child, the podiatrist is looking for abnormal structure or function of the foot and lower extremity, which could lead to either problems during childhood or adulthood. X-rays may be taken of the foot if a significant pathology is noted or suspected. The more severe the flatfoot deformity and the more significant the complaints in the foot or lower extremity, then the more likely the podiatrist will recommend specific treatment for the flatfoot deformity.

Treatment

If the child has a mild flatfoot deformity and no symptoms, then generally no treatment is recommended other than possibly yearly check-ups by the podiatrist. If, however, the child has a moderate to severe flatfoot deformity of has significant symptoms in the foot or lower extremity, then treatment is indicated.

Treatment generally starts with both supportive shoes, such as high tops, and some form of in-shoe insert such as arch padding for the milder cases of flatfoot deformity. More significant cases of flatfoot deformity may require more exacting control of the abnormal motion of the foot such as that offered by functional foot orthotics. Functional foot orthotics limit the abnormal flat arch shape and rolling in of the heel bone during standing, walking and running activities which helps not only improve the appearance and function of the foot, but also greatly reduces the symptoms in the foot or lower extremities. Calf muscle stretching exercises are also commonly prescribed for children with tight calf muscles since the tight calf muscles can worsen the flatfoot deformity with time and make the child's symptoms worse.

If the child has a severe flatfoot deformity and disabling symptoms which does not respond to foot orthotics, shoes and/or stretching, then surgery to correct the flatfoot deformity may be indicated.

These children may be candidates for a 15 minute outpatient procedure to correct the flexible flatfoot deformity which is referred to as hyperpronation. The procedure is called a Subtalar Arthroereisis. It involves the placement of an implant in the space under the ankle joint (sinus tarsi) to prevent only the abnormal motion, but still allowing normal motion. This brief procedure only requires very little recovery time, and is completely reversible, if necessary. Your surgeon can consult you about this exciting, life-changing procedure, or more information can be obtained at www.hyperpronation.com.

Tarsal Coalition

A tarsal coalition is a bone condition that causes decreased motion or absence of motion in one or more of the joints in the foot. The lack of motion or absence of motion is due to abnormal bone, cartilage or fibrous tissue growth across a joint. When excess bone has grown across a joint there is usually little or no motion in that joint. Cartilage or fibrous tissue growth can restrict motion of the affected joint to varying degrees causing pain in the affected joint or in surrounding joints.

The decreased motion can cause pain in surrounding joints as they try to compensate for the affected joint. When one joint has restricted motion the surrounding joints will be stressed more than normal. This is an attempt to "take up the slack" for the diseased joint.

Tarsal coalitions can occur outside of a joint as well. This is referred to as a bar. A bar connects two bones that don't normally touch or have a joint between them. The bar will limit motion in surrounding joints causing abnormal wear and tear to the joints of the foot. This can lead to early arthritis and pain. The bar itself can be painful as well if it is incomplete, traumatized during walking, sporting activities, or an accident.

In the foot, the bones found at the top of the arch, the heel, and the ankle are referred to as the tarsal bones. Thus, a tarsal coalition is an abnormal connection between two of the tarsal bones in the back of the foot or the arch. This abnormal connection between two bones is most commonly an inherited trait and passed down from generation to generation. All coalitions are not inherited though. They can also arise from outside sources such as arthritis, infections, trauma and abnormal bone growth. These outside causes are much less frequent.

Symptoms

Patients with a painful tarsal coalition commonly describe an aching sensation deep in the foot near the ankle or arch. In many cases, muscle spasm on the outside of the affected leg is present. This is a natural reaction of the body as it tries to limit the painful motion occurring in the foot. Patients may notice that the affected foot is not as flexible and appears significantly more flattened when compared to the other foot. This only holds true if only one foot is affected, as it is common for both feet to be affected. All flat-footed people do not have tarsal coalitions. There are many causes of flat feet.

Symptoms most commonly appear in the teenage or early adult years depending on the location of the coalition. It should be noted that not all tarsal coalitions become symptomatic. The onset of symptoms may be delayed into adulthood.

Diagnosis

Diagnosis of a tarsal coalition can usually be made from symptoms described by the patient to the doctor. X-rays are usually taken and in most cases a CT scan or MRI will confirm the diagnosis and provide valuable information regarding the type of coalition, its location, and how the joints have been affected.

Treatment

There are a variety of methods to treat a tarsal coalition depending on the severity of the condition, the age of the patient, and which joint is affected. Conservative treatment involves non-surgical treatment options. Conservative treatment is directed toward reducing motion in the affected joints to decrease pain and muscle spasm. Orthotics (shoe inserts) are commonly used accomplish this decrease in motion. Physical therapy and anti-inflammatory medication may be utilized as well. Cortisone injections in the affected area may provide relief for an indefinite period of time. These conservative methods of treatment may or may not provide long-term relief.

If symptoms do persist surgical correction is often entertained. Surgical intervention will vary depending on the type of coalition, its location, and the amount of arthritis it has caused in the foot. Surgery can involve removing the coalition to allow for more normal motion between the bones. Many times surgery may involve fusing the affected joint or surrounding joints. This is designed to limit or completely stop the painful motion of the affected joints.

Recovery from surgery often involves a period of non-weight bearing on crutches and utilization of a cast. Physical therapy will often be used once the normal bone healing is complete to restore muscle tone and full available range of motion.(For more information see Hindfoot and Ankle surgery.