Brachymetatarsia

The Brachymetatarsie is a congenital shortening of a metatarsal, sometimes on both feet. It is a form of brachyphalangia , even if no phalanx is actually shortened, and is classified as type E brachydactyly . In ancient texts there is also the term "brachymetapody", while a shortening of the metacarpal bones is called brachymetacarpy , and is occasionally associated with brachymetatarsia.

Initial description

Brachymetatarsia was first described as an independent syndrome in 1951 in London at the Galton Institute by the British doctor Julia Bell, for which she evaluated fifteen older case reports .

genetics

An autosomal dominant inheritance is generally suspected. Brachymetatarsia can also be associated with other symptoms and be part of a superordinate syndrome , especially in generalized skeletal dysplasias , Turner syndrome , basal cell nevus syndrome and in connection with Albright osteodystrophy (but not in Albright syndrome ). In Albright's osteodystrophy, brachymetatarsia (usually of the first, fourth or fifth metatarsal bone) and an occasional accompanying shortening of a metacarpal bone (brachymetacarpy) can often be the first clinical signs of an underlying pseudohypoparathyroidism type 1A or, more rarely, type 1B, which already occurs in the Childbirth is present, while other skeletal dysplasias often do not occur until 2-4 weeks. Age, often only become noticeable in adulthood. Information on the frequency of such syndromic brachymetatarsia compared to the isolated occurrence is not available.

clinic

Two-sided shortening of the fourth metatarsal

X-ray of a forefoot with congenital shortening of the fourth metatarsal

The first metatarsal bone is most frequently affected, which means that the big toe is significantly shorter and the normal rolling process of the foot over the ball of the big toe is disturbed, which can lead to increased stress on the second and third toes and metatarsalgia (forefoot pain) due to disturbance of the so-called transverse arch . However, the first metatarsal bone is slightly shorter than the second metatarsal bone in 40% of all people, and brachymetatarsia I is only present if it is significantly shortened.

In addition, all other metatarsal bones can be affected, the fourth being the most common shortened metatarsal bones next to the first. The toe, which is actually not shortened, stands with its base that is closer to the body (more proximal) but overlies the neighboring toes and sometimes forms pressure points. But this is often more of a cosmetic than an orthopedic problem.

therapy

The treatment of shortening the first metatarsal bone serves to avoid overloading the smaller neighboring toes, while shortening the second to fifth metatarsal bones is more of a cosmetic indication. As a rule, the completion of the growth should be awaited, i.e. a correction should not be carried out before the age of 16.

A metaphyseal osteotomy close to the base of the shortened metatarsal bone is usually performed to lengthen it . A small external fixator is then used to slowly distract the callus until the desired length is achieved. The fixator cannot be removed until the new bone is sufficiently strong and stable.

In the case of minor shortenings, a lengthening corrective osteotomy can also be performed, in which the metatarsal bone is cut lengthways and then distracted and then fixed by means of a small osteosynthesis . The effort is less, the bone healing faster, but the complications are higher and the length cannot be readjusted.

Before a surgical correction, a check of the parathyroid hormone level is recommended in order to rule out undetected pseudohypoparathyroidism.

Literature and individual references

1. ↑ G. Adler, G. Burg, J. Kunze, D. Pongratz, A. Schinzel, J. Spranger: Leiber - The clinical syndromes. Syndromes, sequences and symptom complexes . Volume 1: Disease pictures , entry brachydactyly type E , page 122; 8th edition 1996, Verlag Urban & Schwarzenberg Munich ISBN 3-541-01718-X
2. ↑ ^{a b} Amita Sharma, Alfred J. Phillips, Harald Jüppner: Hypoplastic metatarsals - beyond cosmesis New England Journal of Medicine Volume 373, Issue 22 of November 26, 2015, pages 2189-2190, doi: 10.1056 / NEJMc1508520
3. ↑ JA Herring: Tachdijan's Pediatric Orthopedics. ; Volume 3, Chapter Pseudohypoparathyreoidism pages 1703-1704; 3. Edition; WB Saunders Company, Philadelphia (USA) 2002; ISBN 0-7216-5682-X
4. ↑ F. Hefti: Pediatric Orthopedics in Practice . Chapter 3.4.5.9: Brachymetatarsie page 417; Springer-Verlag, Berlin 1997, ISBN 3-540-61480-X

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