Congenital amputations are missing or incomplete limbs at birth. Mechanism can involve primary intrauterine growth inhibition or secondary intrauterine destruction of normal embryonic tissues. Etiology is often unclear, but teratogenic agents (eg, thalidomide) and amniotic bands, which are loose strands of amnion that entangle or fuse with fetal tissue, are known causes.
Limb deficiencies can be
In transverse deficiencies, all elements beyond a certain level are absent, and the limb resembles an amputation stump. Amniotic bands are the most common cause; the degree of deficiency varies based on the location of the band.
Longitudinal deficiencies involve specific maldevelopments (eg, complete or partial absence of the radius, fibula, or tibia). They may result from syndromes or associations such as VACTERL (vertebral anomalies, anal atresia, cardiac malformations, tracheoesophageal fistula, renal anomalies and radial aplasia, and limb anomalies).
Infants with transverse or longitudinal limb deficiencies may also have hypoplastic or bifid bones, synostoses, duplications, dislocations, or other bony defects; eg, in proximal femoral focal deficiency, the proximal femur and acetabulum do not develop. One or more limbs may be affected, and the type of defect may be different in each limb. CNS abnormalities are rare. X-rays are essential to determine which bones are involved.
Treatment consists mainly of prosthetic devices, which are most valuable for lower-limb deficiencies and for completely or almost completely absent upper limbs. If any activity in an arm or hand exists, no matter how great the malformation, functioning capacity must be thoroughly assessed before a prosthesis or surgical procedure is recommended. Therapeutic amputation of any limb or portion of a limb should be considered only after evaluating the functional and psychologic implications of the loss and when essential for fitting a prosthesis.
An upper-limb prosthesis should be designed to serve as many needs as possible so that the number of devices is kept to a minimum. Children use a prosthesis most successfully when it is fitted early and becomes an integral part of their body and body image during the developmental years. Devices used during infancy should be as simple and durable as possible; eg, a hook rather than a bioelectric arm. With effective orthopedic and ancillary support, most children with congenital amputations lead normal lives.
Last full review/revision January 2010 by Gregory S. Liptak, MD, MPH