Delta Phalanx (longitudinally bracketed epiphysis)
- classic delta phalanx is characterized by a triangular or trapezoidal shaped bone w/ C shaped epiphyseal plate;
- proximal epiphysis curves around from its transverse orientation to a longitudinal one from proximal to distal along one side of the
phalanx, thus forming a "C"'
- this results in a trapezoidal phalanx;
- longitudinal growth is impossible and angulation inevitable;
- aberrant epiphysis ossifies from proximal to ditsal, causing unequal longitudinal growth and angulation of the distal portion of digit;
- abnormality is most common in the proximal phalanx of the thumb and little finger;
- deformity most often occurs bilaterally, and sometimes has an autosomal dominant inheritance;
- whenever more than one delta bone is present in one hand, it is associated w/ other abnormalities including the hypoplastic hand &
- delta phalanx has been associated with syndactyly, polydactyly, symphalangism, clubfoot, Apert's syndrome, & Poland's syndrome;
- Surgical Indications:
- deformity that is unsightly and awkward;
- significant deviation which interferes w/ development of normal use of the finger;
- surgery should be delayed as long as possible to allow developmental size and maturity to faciliate surgery;
- Treatment Options:
- abnormal (longitudinal) portion of epiphyseal plate should be removed, while horizontal portion of physis is preserved;
- excision of abnormal part of physeal plate results in resumption of more normal growth;
- in infants, transverse resection of abnormal epiphysis (longitudinal bracket) appears to work well for initial correction;
- this correction may not be maintained, & additional osteotomies may be required;
- opening wedge osteotomy:
- this is accomplished by an opening wedge osteotomy on narrow side of the trapezoidal phalanx;
- insertion of iliac crest bone into wedge gives satisfactory correction, but this may have to be repeated as growth continues;
- reversed wedge osteotomy: (preferred)
- reversed wedge osteotomy may be performed in which a wedge of bone is taken from the the mid aspect of the delta phalanx which
is then reversed and replaced inorder to both straighten the digit and to disrupt the longitudinal epiphysis
Congenital triangular bones in the hand.
The longitudinal epiphyseal bracket: Implications for surgical correction.
Osteotomy for correction of "delta phalanx" deformity.
Original Text by Clifford R. Wheeless, III, MD.
Last updated by Data Trace Staff on Tuesday, May 22, 2012 9:48 am