Weinstein Lovell and Winters Pediatric Orthopaedics 7e

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CHAPTER 30  |  The Child with a Limb Deficiency

Congenital skeletal limb deficiencies

Terminal deficiencies

Intercalary deficiencies

There are no unaffected parts distal to and in line with the deficient portion

Middle portion of limb is deficient but proximal and distal portions are present

esrevsnarT

laixaraP

lartneC Entire central portion of limb absent with foreshortening

laixaraP

Defect extends transversely across the entire width of limb

Only the preaxial or postaxial portion of limb is absent

Segmental absence of preaxial or postaxial limb segments intact proximal and distal

Incomplete phocomelia

Radial hemimelia

Amelia

Ulnar hemimelia

Radial hemimelia

Ulnar hemimelia

Incomplete hemimelia

Complete phocomelia

Complete hemimelia

Tibular hemimelia

Fibular hemimelia

Fibular hemimelia

FIGURE 30-1.  Diagrammatic representation of the Frantz and O’Rahilly classification of congenital limb deficiencies. (From Frantz C, O’Rahilly R. Congenital skeletal limb deficiencies. J Bone Joint Surg Am 1961;43:1202, with permission.)

Epidemiology and Etiology Pediatric limb deficiency is uncommonly encountered by most pediatric orthopaedic surgeons. Depending on which global location is being considered, either congenital or acquired deficiencies may predominate. Congenital defi- ciencies are more common in developed nations (3), while traumatic amputations can predominate in lesser developed nations (4). Tumors are an uncommon but important cause of limb deficiency in children in all locations. Because limb deficiency is uncommon, patients are often treated in tertiary organized programs that have the experience and resources to treat these patients. Depending on the methods used, the calculated incidence may vary widely, from 6 per 10,000 in British Columbia (5) to 310 per 10,000 in Tayside, Scotland (6). In a survey of European countries participating in the International Clearing House for Birth Defects Monitoring Programme, the inci- dence was between 3.1 and 7.9 per 10,000 (7). Statistics such as these are more accurately determined by well-collected birth registries and less accurately determined by surveys from pros- thetic clinic medical records, which can overestimate incidence if the clinic is a tertiary referral center. Fibular deficiency is the most common cause of long bone congenital limb deficiency, when considering that fibu- lar deficiency often accompanies femoral deficiency. Femoral deficiencies are the next-most common, with an incidence between 1 in 50,000 and 1 in 200,000 live births. Femoral deficiencies include the spectrum of the congenital short

femur with a stable hip joint and a knee without significant contracture to proximal femoral focal deficiency (PFFD). The prevalence of tibial deficiencies is far less than either ­fibular or femoral deficiencies and is reported to be approximately one per million live births. The incidence of all upper extremity amputations is not precisely known but is thought to be more than lower extremity amputations and more often congenital and bilateral than acquired (8, 9). The most common congenital upper extremity amputation is by far the transverse forearm (below-elbow) amputation, with radial longitudinal deficiency being the next- most common. In reality, few pediatric orthopaedic surgeons, other than those working in a limb-deficiency program, will have much experience with these amputations. Although the physician should strive to understand the cause of a congenital amputation in all cases, most of the time no identifiable cause exists. Limb deficiencies can be caused in several ways, such as by environmental factors, genetic disorders, vascular anomalies (such as “the subclavian artery supply disruption sequence”), (10) and amniotic bands. The oldest and most commonly held etiology for congen- ital amputation in the past was the mechanical amputation of limbs by amniotic bands, or Streeter dysplasia. Streeter postu- lated that the bands caused an intrinsic defect in the growth of the fetal limb (11). There is, however, evidence that amniotic bands can form a constriction around the developing limb that interferes with the growth of the limb. The resulting constric- tion can lead to any degree of damage, from a constriction band around a limb that is otherwise normal to a ­complete