Groningen, The Netherlands
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Complaint: extra toe.
Assessment: there are more than 5 toes.
tibial polydactyly (preaxial polydactyly, extra big toe)
fibular polydactyly (postaxial polydactyly, extra little toe)
central polydactyly (extra middle toe)
fibular dimelia (mirror foot)
Explanatory note: polydactyly. This is a relatively frequent congenital abnormality. The incidence is 1.7 in a 1000 births. In 50 % of the cases the abnormality is bilateral, but does not need to be symmetrical. In 34 % of the cases there is also polydactyly in the hands. Toe polydactyly may occur in combination with syndactyly or other congenital deformities such as aplasia of the tibia and can be part of a syndrome (Table 14.1).
Syndromes with polydactyly
Ellis-Van Creveld syndrome
Tibial polydactyly. An extra big toe is less frequent than an extra little toe and there also may be a hallux varus (Fig. 14.1).
Tibial polydactyly (extra big toe). Next to the extra big toe (blue arrow) there is also a hallux varus (red arrow)
Fibular polydactyly. In 80 % of the cases the extra toe is on the lateral side (Fig. 14.2).
fibular polydactyly (extra little toe)
Central polydactyly. An extra middle toe is rare.
Fibular dimelia is also called mirror foot because the fibular part of the lower leg and the foot are mirrored. This is a very rare deformity occurring probably in 1 in 1,000,000 births. There is a duplication of the fibula and the fibular side of the foot, whilst the tibia and tibial part of the foot are absent (Fig. 14.3). The big toe is always absent. The parts of the mirror foot do not need to be completely symmetrical. The knee and the ankle are absent and the lower leg is usually shortened and the foot has an equinovarus deformity. The upper leg may also be too short.
fibular dimelia (mirror foot). Absent tibia and medial part of the foot. Duplication of the fibula and lateral part of the foot. In this case 8 toes
There may also be an ulnar dimelia and a proximal focal femoral deficiency. Apart from these other congenital abnormalities of the skeleton may be present such as a scoliosis, a synostosis between the radius and ulna, hand abnormalities such as a thumb with 3 phalanges (triphalangeal thumb). Other congenital abnormalities may frequently be present such as a ventricular septum defect, an absent kidney and undescended testicles.
Supplementary assessment: X-rays of both lower extremities.
Primary care treatment: none.
When to refer: the most optimal time for operative treatment is between 9 and 12 months of age. Therefore a child should be referred earlier.
Secondary care treatment: polydactyly. Surgery is recommended between 9 and 15 months of age. The most medial big toe or most lateral small toe will generally be removed notwithstanding the fact that these may look more normal than the adjacent toe. In a central polydactyly ligaments may need to be transfered in to different positions in order to prevent the forefoot from becoming deformed or widened. Following central polydactyly surgery a cast will be left in place for about 6 weeks.
An exarticulation through the knee joint will be carried out if there is a normal femur. A fusion will be carried out between the femur and one of the fibulae if the femur is shorter than normal as in a possible present proximal focal femoral deficiency. A Syme amputation can then be carried out at the level of the talocrural joint.
Giant Toe Growth
Complaint: one or more toes are obviously much bigger than normal at birth.
Assessment: hypertrophy of one or more toes.
Explanatory note: macrodactyly. The involved toes are about 1.5 times longer and broader than normal at birth. Giant growth appears mostly in the second toe followed by the big toe. The hypertrophy involves not only the bony structures but also the soft tissues including the nerves. The nerves may sometimes be 10 times as thick as normal. There is also a syndactyly in 10 % of the cases (Fig. 14.4).
(a) Macrodactyly of the right big and second toes. (b) Macrodactyly of the left big, second and third toes, with a syndactyly of the second and third toes
Initially the joints of the involved toe (toes) move normally. At the end of the growth period they are generally stiff and early arthritis particularly in the interphalangeal joints can occur. Macrodactyly is usually unilateral. There are 2 types: a static and a progressive type.
Static Type. The size of the involved toe (toes) remains constant during growth with regard to the rest of the foot.
Progressive Type. The involved toe (toes) will become disproportionally larger than the rest of the foot during growth. The deformity usually appears as an isolated condition. The cause is unknown. However, macrodactyly can be a part of a syndrome such as: neurofibromatosis1 (Von Recklinghausen disease), Klippel-Trenaunay-Weber syndrome1 and the Proteus syndrome1. This is almost always part of a syndrome if the macrodactyly is present in more than one extremity or in the case of proximal extension with the passage of time.
Supplementary assessment: X-rays of the foot.
Primary care treatment: none.
When to refer: the parents usually want early advice from a specialist.
Secondary care treatment: macrodactyly. Epiphysiodesis of the involved metatarsal and proximal phalanx with debulking of the extra soft tissues in girls when the shoe size reaches 38 and in boys 40 (European shoe size). Part of the end of the toe can be amputated if necessary or the metatarsal bone can be shortened. A ray resection is the best treatment if one metatarsal bone is involved in this process but not if the first ray is involved. A first ray resection is contraindicated because the first ray has an important function when walking. In that case more operations are often necessary in order to remove the hypertrophic soft tissues. In extreme cases a Syme amputation at the level of the talocrural joint may be necessary.
Bent Toe Deformity
Complaint: the parents complain about the child’s bent toe.
Assessment: flexed toe.
Explanatory note: curly toe. The curly toe is the most frequent inborn error of the little toes. Usually it is a familial problem which appears bilaterally and in general gives no complaints. The most involved toes are the fourth and fifth toe. The distal phalanx of the toe is medially deviated, flexed and externally rotated. The involved toe lies under the medial toe next to it (Fig. 14.5). The deformity is most obvious when the child stands. This anomaly improves spontaneously in 25 % of cases. The children have no complaints in most cases, and a flexor tenotomy is rarely required for a persistant deformity.
Curly toes of the right and left little toe
A congenital hammer toe is characterized by extension in the metatarsophalangeal joint, flexion in the proximal interphalangeal joint and extension in the distal interphalangeal joint (Fig. 14.6). The hammer toe has no rotational component in contrast to the congenital curly toe. The deformity is often bilateral and is a familial problem. It usually involves the second toe.
(a) Hammer toe. (b) Mallet toe. (c) Claw toe
In a congenital mallet toe there is a flexion deformity in the distal interphalangeal joint usually involving one toe (Fig. 14.6). Normally there are no complaints in young children. Complaints generally occur in young adults.
A claw toe is characterized by hyperextension at the level of the metatarsophalangeal joint that is often subluxated dorsally with flexion at the level of the proximal and distal interphalangeal joints (Fig. 14.7).
Claw toes. (a) During childhood and (b) In adulthood
Usually all of the toes are involved in contrast to the mallet toe often including the big toe with a flexion contracture at the level of the interphalangeal joint. Claw toes are often seen in pes cavus (hollow feet) and neurological conditions such as Charcot-Marie-Tooth disease, encephalopathy and after poliomyelitis.
Supplementary assessment: none.
Primary care treatment: treatment is not necessary if there are no complaints.
When to refer: only with complaints. The complaints are usually caused by pressure areas as a result of the abnormal position of the toes.
Secondary care treatment: curly toe. Tenotomy of the flexor digitorum longus tendon and possibly flexor digitorum brevis, in children older than 6 years of age with complaints.
Hammer toe and claw toe
Tenotomy of the flexor digitorum longus tendon with lengthening of the extensor tendon if necessary. A resection arthrodesis of the proximal interphalangeal joint and fixation with a Kirschner wire or a toe fixation nail during 3–4 weeks in young adulthood.
Tenotomy of the flexor digitorum longus. A resection arthrodesis of the distal interphalangeal joint in young adulthood.
Complaint: one toe lies above another toe.
Assessment: the little toe usually lies on top of the fourth.
Diagnosis: digitus superductus (overlapping toe)
Explanatory note: digitus superductus. Overlapping toes is an inborn error generally involving the little toe which lies over the fourth toe, so-called digitus quintus superductus (Fig. 14.8). The deformity is usually familial and is generally bilateral. The digitus quintus superductus gives problems at puberty when wearing shoes in about half of the cases. The toes can also lie above or under the toe next to it, usually the second toe crossed over or under the third toe (Fig. 14.9). The other toes usually do not cause complaints in children in contrast to the little toe.
Supplementary assessment: none.
Primary care treatment: conservative methods, such as orthoses and tape, are ineffective.
When to refer: only if there are complaints.
Secondary care treatment: digitus superductus. Many operations have been thought of to deal with this problem. The Butler operation is most frequently performed. A racket incision is made with the handle on the dorsal side with a tenotomy of the extensor tendon and an incision through the capsule on the dorsal and medial side of the metatarsophalangeal joint. The toe can now be easily corrected. The skin will be sutured in the corrected position. In another method the proximal phalanx will be completely or partly excised. In that case the toe becomes floppy and it is a good idea to suture the fifth toe partially onto the fourth toe (artificial soft tissue syndactyly).
Overlapping of the little toe over the fourth toe (digitus quintus superductus). (a) In childhood. (b) In adulthood
Overlapping of the right second toe on the third toe (digitus superductus)
Complaint: one or more toes are too short.
Assessment: one or more toes are too short (Fig. 14.10).
Explanatory note: brachydactyly. In the foot the fourth ray is usually shortened. The involved metatarsal bone (or metatarsals) is (are) shorter than the other metatarsals. Generally it is part of an autosomal inborn deformity. Brachydactyly can also be part of a syndrome such as pseudohypoparathyroidism2 (Albright’s hereditary osteodystrophy).
Supplementary assessment: not necessary.
Primary care treatment: none.
When to refer: this is usually a cosmetic problem. Referral can be made in rare cases when there are functional problems.
Secondary care treatment: brachydactyly. A lengthening of the involved metatarsal may be considered in exceptional cases. The metatarsal can be lengthened directly 10 mm in one operation or 30 mm can be achieved with gradual distraction.
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