How To Treat Polysyndactyly And Syndactyly Of The Foot

Edwin Harris, DPM, FACFAS

   Central polysyndactyly. The most frequent form is duplication of the distal phalanx. One can recognize this clinically by the presence of two distinct nail plates. Involvement of the middle and proximal phalanx is much less frequent.

   Fibular polysyndactyly. There are two distinct forms. The most common form is duplication of the distal phalanx of the fifth toe and syndactyly with the fourth toe. Less common is duplication of all three phalanges of the fifth toe and a metatarsal vestige with syndactyly to the fourth toe. On occasion, there is duplication of the segments of the fifth toe with anomalies of the fifth metatarsal head that take the form of a V- or Y-shaped fifth metatarsal. A complicating factor in this form is abnormal sagittal plane position of one or both of the abnormal segments of the fifth metatarsal. This can lead to abnormal weightbearing from plantarflexion of one of the bifid metatarsal head segments. There may be abnormalities in the proximal phalanx and the middle phalanx that can make it difficult to determine the segment to be deleted.

Essential Treatment Considerations

The goals and objectives of treatment of congenital abnormalities of the lesser toes should include pain relief, proper alignment of the toes and comfort when the patient is wearing shoes.28

   There are some general rules that hold true for surgical repair of syndactyly, polydactyly and polysyndactyly. With some exceptions, surgeons can best treat most syndactyly on the fibular side of the foot by deleting the lateral segment. On the other hand, when it comes to most cases of tibial polydactyly, surgeons best manage these cases by deleting the medial segment.

   Central polydactyly poses some difficulties. First, it is difficult to decide which is the abnormal ray or rays. A good rule is to identify the ray that is either abnormally long or abnormally short. The surgical dilemma is that resection of the ray itself does not narrow the foot and reconstruction of a cosmetically acceptable web space is extremely difficult. Physicians must give additional attention to the abnormalities in the tarsus.

   Central syndactyly also presents a surgical dilemma in the decision to intervene. Unless there is discrepant growth in the two toes, there is no medical indication to separate the toes. There are two exceptions. First, syndactyly repair would be justified if there were progressing deformity because of asymmetrical growth. Second, on rare occasions, psychological issues may become so severe that an attempt at desyndactyly becomes justified.

   Fibular polysyndactyly usually causes clinical symptoms. There may be difficulty with foot hygiene. Very frequently, there are issues with shoe gear fitting. The decision on which segment needs deletion depends on the anatomy of the deformity. Alignment is critical but one must also take the final cosmetic appearance into account.

   Fibular polydactyly can present some difficult surgical planning issues and treatment is influenced by the anatomy of the fifth metatarsal. In most cases, the lateral segment will be the one surgeons choose for deletion. If the fifth metatarsal head is large transversely after deletion of the lateral segment, the head will need debulking and narrowing.

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