Congenital conditions affecting the upper extremity are observed in 1 in every 600 to 700 live births. These conditions derive from failure of upper limb development during gestation. Surgical intervention is often warranted to correct functional limitations and minimize aesthetic differences for both the child and their family. Conditions like syndactyly, polydactyly, thumb hypoplasia, and constriction band syndrome often undergo surgical intervention due to the limited potential complications but substantial functional and aesthetic benefits. Therapy and continual observation may be a more ideal treatment strategy for other conditions such as radial longitudinal deficiency or type I polydactyly if it does not infringe on prehension function or if the patient has been able to compensate accordingly. Should surgical intervention be elected, it typically is performed within the first 2 years of age or soon after functional limitations are present. Corrective surgeries of congenital conditions affecting the hand aim to provide bilateral symmetry, adequate prehension, and regain functional upper extremity ability for children while minimizing aesthetic differences, where possible.
24 Congenital Conditions of the Upper Extremity and Hand
Congenital hand differences vary in their functional and aesthetic implications.
Fibroblast growth factors regulate sonic hedgehog (SHH) gene which is responsible for proper limb structures development from the limb bud.
Understanding the affected axis can provide insight on the underlying etiology of the abnormality:
1 per 300 to 1 per 3,000 births.
More common in African–American population than Caucasian.
Type IV is the most common (43%) followed by Type II (15%).
Typically, unilateral and random.
Exact etiology is not well known.
Central: Duplication at the midline.
Postaxial: Small finger duplication (► Fig. 24.2):
1. Surgical Treatment
Preaxial: Goal is to reconstruct a thumb that attains bilateral symmetry while preserving pinch function:
Types I, II, and III: Bilhaut-Cloquet procedure involves removing central tissue and combining both digits into one.
Types III and IV: Type 2 combination technique preserves skeleton and nail of one component and augment with soft tissue from other digit; ablation of lesser digit.
Types V, VI, and VIII: Type 3 combination technique involves segmental digital transfer.
Central: Goal is to remove extra digit in order to prevent angular growth deformities.
Osteotomy and ligamentous reconstructions.
Postaxial: Goal is typically to remove lesser digit:
Type A: Reconstruction with Type 2 combination technique preserves radial digit, radial collateral ligaments, and muscular structures.
Type B: Suture ligation—tie off in nursery or amputate before age 1, essentially inducing avascular necrosis to the rudimentary digit.
Syndactyly occurs secondary to failure of apoptotic mechanisms that typically create webspaces between digits between weeks 6 and 8 of gestation. 6
Disturbed Wnt signaling and gap junction protein function lead to syndactyly. 2
Constriction band syndrome.
Connection of adjacent digits (► Fig. 24.3).
Described by degree of connection:
Complete: Connected the full length of the digits (► Fig. 24.3a).
Incomplete: Proximal connection of adjacent fingers (► Fig. 24.3b).
Described by type of connected tissue:
Simple: Connected by skin only.
Complex: Skeletal, muscular, and cutaneous fusion of adjacent digits
Synechia: Unique condition where all digits (index to small) are completely connected as well as a connection between the nail plates.
Hand function and aesthetic preference are the primary determinants of whether surgical intervention is warranted.
1. Nonoperative Management
Simple, incomplete cases can be addressed according to patient and family’s preference as these presentations do not substantially limit hand function.
2. Surgical Treatment
Complete, complex syndactyly with nail involvement (flag and pennant technique—use skin from pulp of each digit to reconstruct the lateral nail fold).
Interdigitating zigzag flaps to avoid longitudinal scarring.
Partial syndactyly can be treated with skin flaps with possible application of skin grafts or skin graft alternatives:
Full-thickness skin grafts are standard to obtain skin coverage following digital separation.
Recurrent web creep or resyndactylization is the most common complication following digital release.
IV. Thumb Hypoplasia
1 per 30,000 live births. 7
Exact etiology is not well known. 8
On the radial longitudinal deficiency spectrum; therefore, associated organ system conditions may be affected as well. 8
VACTERAL (vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, renal anomalies, and limb abnormalities).
Thrombocytopenia absent radius (TAR).
1. Nonoperative Management
Type I: Observation is warranted to ensure that thumb and hand function are not substantially limited.
2. Surgical Treatment
V. Radioulnar Synostosis
Very rare congenital disorder with only 350 cases reported in the literature. 13
Affects males more than females.
Failure of differentiation of the cartilaginous precursors into the radius and ulna in week 7 of gestation.
One out of five cases positive with family history: Autosomal dominant inherence pattern.
Associated conditions in 30% of cases:
Sex chromosome abnormalities