Congenital limb deficiencies occur in about 0.1 to 0.2 in 1000 children, or about one-tenth the frequency of clubfeet or DDH.
Most deficiencies occur in children who are otherwise normal, and they have no genetic basis. Thalidomide is known to cause multi-limb deficiencies. Most limb deficiencies are sporatic. Tibial hemimelia is transmitted as a dominant trait. In other cases, deficiencies are associated with various syndromes such as the radial aplasia–thrombocytopenia syndrome. Acquired amputations result from trauma or treatment of malignant tumors.
The most widely accepted nomenclature is that of Frantz and O’Rahilly, which divides limb deficiencies into intercalary and terminal types. Every type of deficiency is usually classified. These classifications aid in defining severity and indicating treatment methods (see Chapters 4 and 9 for details of treatment).
Males with limb deficiencies outnumber females 3:2, and lower extremities are twice as affected as upper. In 80% of cases, single limbs are involved. Congenital causes are three to four times more frequent than acquired amputations.
Most deficiencies are associated with limb shortening. Order comparative radiographs if a reduction deformity is suspected. Classify the deformity according to the radiographic appearance. Classification is more difficult early on because of lack of ossification. Consider possible associated problems, especially in children with radial deficiencies.
Refer most patients to a limb deficiency clinic. Such clinics provide several important resources for the family:
- geneticists to evaluate for possible associations and provide family genetic counseling,
- families to provide support groups,
- prosthetics to provide often complex fitting problems,
- orthopedic surgeons to provide overall management.