Congenital Upper Limb Anomalies 171anomalies resulting from mutations/disruptions in this molecular machinery.
Congenital Upper Limb Anomalies (CULA) have since been described as
malformations, deformations (including disruptions), or dysplasia of the upper
extremities during embryonic development resulting in an atypical limb
phenotype at birth.
The categories included in the definition above are the basis for the Oberg,
Manske, Tonkin (OMT) classification of CULA and describe/convey
etiological associations as well as phenotype (Table 1). Malformations are
caused by intrinsically abnormal processes during limb development.
Deformations are abnormal forms, shapes or positions of the limb that result
from mechanical forces interfering with the normal developmental process.
Dysplasia refers to the abnormal organization of cells into tissue. The Oberg,
Manske, Tonkin (OMT) classification was proposed in 2010 and subsequently
adopted (as of 2014) by the International Federation of Societies for Surgery
of the Hand (IFSSH) (Oberg et al., 2010; Ezaki et al., 2014).
EPIDEMIOLOGY
The incidence of CULA in the US and worldwide is underestimated
mainly because reporting these anomalies is not mandated in many
jurisdictions as well as the fact that many musculoskeletal disabilities are
grouped together. What has been studied and reported, however, highlight
congenital malformations as the leading cause of infant mortality and also
accounts for 12% of all pediatric hospitalizations (Egbe et al., 2015). Data
from the European Surveillance of Congenital Anomalies (EUROCAT) show
that congenital limb anomalies account for almost 16% of all anomalies. In
Sweden, CULA have been reported with an incidence of 21.5 per 10,000 (~ 1
in 500) live births (Ekblom et al., 2014). Previous reports estimate the
prevalence of congenital hand anomalies to be 11.4 (Lamb et al., 1982) in
Scotland, and 19.7 (Giele et al., 2001) per 10,000 live births in Western
Australia. These different studies could reflect biologic variability in regional
populations, a relative increase in the apparent prevalence of CULA, or
regional differences in reporting/recognition of hand abnormalities.
Irrespective, the data suggest that CULA are one of the most common
malformations recognized at birth.