Weinstein Lovell and Winters Pediatric Orthopaedics 7e

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CHAPTER 30  |  The Child with a Limb Deficiency

Classification of Congenital Skeletal Limb Deficiencies

TABLE 30.1

Terminal (T)

Transverse (-)

Longitudinal (/)

1. Amelia (absence of limb)

1. Complete paraxial hemimelia (complete absence of one of the forearm or leg elements, and of the corresponding portion of the hand or foot)—R, U, TI, or FI a 2. Incomplete paraxial hemimelia (similar to the above, but part of the defective element is present)—r, u, ti, or fi a 3. Partial adactylia (absence of one to four digits and their ­metacarpals or metatarsals): 1, 2, 3, 4, or 5 4. Partial aphalangia (absence of one or more phalanges from one to four digits): 1, 2, 3, 4, or 5

2. Hemimelia (absence of forearm and hand or leg and foot)

3. Partial hemimelia (part of forearm or leg is present)

4. Acheiria or apodia (absence of hand or foot)

5. Complete adactylia (absence of all five digits and their ­metacarpals or metatarsals) 6. Complete aphalangia (absence of one or more phalanges from all five digits)

Intercalary (I)

Transverse (-)

Longitudinal (/)

1. Complete phocomelia (hand or foot attached directly to trunk)

1. Complete paraxial hemimelia (similar to corresponding terminal defect but hand or foot is more or less complete)—R, U, TI, or FI a 2. Incomplete paraxial hemimelia (similar to corresponding terminal defect but hand or foot is more or less complete)—r, u, ti, or fi a 3. Partial adactylia (absence of all or part of a metacarpal or ­metatarsal): 1 or 5 4. Partial aphalangia (absence of proximal or middle phalanx, or both, from one or more digits):1, 2, 3, 4, or 5

2. Proximal phocomelia (hand and forearm, or foot and leg, attached directly to trunk) 3. Distal phocomelia (hand or foot attached directly to arm or thigh)

-, transverse; /, longitudinal; 1, 2, 3, 4, or 5 denotes the digital ray involved; FI or fi, fibular; I, intercalary; R or r, radial; T, terminal; TI or ti, tibial; U or u, ulnar. A line below a numeral denotes upper limb involvement; for example, T-2 represents terminal transverse hemimelia of the upper limb. A line above a numeral ­denotes

lower limb involvement; for example, I-1 represents intercalary transverse complete phocomelia of the lower limb. a In capital letters when the paraxial hemimelia is complete, in small letters when the defect is incomplete. From Frantz C, O’Rahilly R. Congenital skeletal limb deficiencies. J Bone Joint Surg Am 1961;43:1202, with permission.

transverse amputation. The previously developed limb has actually been recovered at the time of birth, indicating the mechanism (12). Evidence suggests that most amniotic bands cause deficiency within the first month postconception, based on the fact that limbs and organs commonly affected together are located in close proximity in the embryonic, but not fetal, stage of development (13). Most children with amniotic band syndrome additionally have either craniofacial abnormalities or other evidence of band formation. Modern genetics has shown that the development of the limb is a complex phenomenon that requires the precise interaction of a large number of genes and their effects, which are described in Chapter 1 and other review articles (14, 15). Many of the proteins and growth factors that participate in this complex interaction have been elucidated (16). Genetic causes of limb deficiency can include chromosomal abnor- malities (trisomy 18 and radial longitudinal deficiency), as well as single-gene defects, which result in deficiencies that closely ­follow Mendelian genetic transmission patterns (tibial

deficiency, cleft hand and foot, radial longitudinal deficiency). Even the so-called sporadic deficiencies are more common in families with a history of similar deficiencies. A recent study from the Medical Birth Registry of Norway showed that chil- dren born to a mother with a limb deficiency had a relative risk of 5.6% of having the same defect as the mother (17). This is similar to the relative risk of clubfoot. These facts carry conse- quences for genetic counseling. Understanding the cause of the deficiency is important to the resolving of the guilt that par- ents will ­initially feel. The possibility of a transmissible defect is certainly something both they and their affected offspring will also need to know. For the physician, knowing the exis- tence of medical comorbidities and the natural history of the syndrome is necessary for the care of the child. The disruption of the subclavian artery and its blood sup- ply to the tissues explains the overlap of many of the common orthopaedic conditions seen, for example, Poland syndrome, Klippel-Feil syndrome, Mobius syndrome, Sprengel deformity, and transverse limb deficiencies. There are several possible