guidebook. - Fanconi Anemia Research Fund

106
Fanconi Anemia: Guidelines for Diagnosis and Management
The thumb must be monitored for alignment and length
until skeletal maturity. A wedge-shaped extra phalanx
causes deviation of the thumb, and treatment is recommended.
A small bone is excised and the adjacent
ligaments are reconstructed. A large and wedge-shaped
extra phalanx produces deviation and excessive length.
Simple excision of the phalanx is not recommended
as post-operative instability is common. Fusion of the
abnormal phalanx with an adjacent phalanx along with
removal of a wedge of bone is a better option. This procedure
eliminates the extra joint, shortens the digit, and
realigns the thumb.
Thumb duplication
Duplication of the thumb (pre-axial polydactyly) can be
partial or complete and has been classified into various
types depending on the degree of skeletal replication
(Figure 8 and Table 2). In this classification, the extent
of duplication is defined by whether the components
are attached proximally (bifid) or completely separated
(duplicated).
Figure 8: One-year-old child with a duplicated right thumb prior
to surgical correction. (Courtesy of Shriners Hospital for Children,
Philadelphia)