Mateusz Gładysz FESSH prep

FESSH prep Congenital hand

Ulnar (postaxial) polydactyly

Last reviewed v1.0

FESSH-094Congenital hand●○○ basic

Regarding ulnar (postaxial) polydactyly of the hand:

  1. 1.Type B (rudimentary, pedunculated) postaxial polydactyly is about nine times more common in Black than in white newborns.

  2. 2.In a newborn screening study, most infants with type B postaxial polydactyly had no family history of the anomaly.

  3. 3.An associated syndrome is considerably more frequent with type A (well-formed) than with type B (rudimentary) ulnar polydactyly.

  4. 4.In type A ulnar polydactyly, the extra digit most often arises at the level of the metacarpophalangeal joint.

  5. 5.Pooled data show that suture ligation of type B ulnar polydactyly has a complication rate similar to that of surgical excision.

FESSH marking: +1 per correct statement, 0 for blank, −1 for incorrect. Click the same TRUE/FALSE button twice to clear it.

Question ID
FESSH-094
First published
Last reviewed
Version
v1.0
Answer key and explanations — open after answering

  1. 1. Type B (rudimentary, pedunculated) postaxial polydactyly is about nine times more common in Black than in white newborns.

    True

    In Watson and Hennrikus's prospective screening of 11,161 newborns, the prevalence of postaxial type B polydactyly was 1 in 143 live births of Black infants and 1 in 1339 of white infants. In a Latin-American registry, postaxial polydactyly of the hand was likewise associated with African Black ethnicity.

    • Watson BT, Hennrikus WL. Postaxial type-B polydactyly. Prevalence and treatment. J Bone Joint Surg Am. 1997;79(1):65-8. PMID 9010187
    • Castilla EE, da Graca Dutra M, Lugarinho da Fonseca R, Paz JE. Hand and foot postaxial polydactyly: two different traits. Am J Med Genet. 1997;73(1):48-54. PMID 9375922

  2. 2. In a newborn screening study, most infants with type B postaxial polydactyly had no family history of the anomaly.

    False

    In the same screening study, 18 of 21 affected infants (86%) had a family history of the anomaly. Registry data on postaxial polydactyly of the hand also show frequent recurrence in first-degree relatives.

    • Watson BT, Hennrikus WL. Postaxial type-B polydactyly. Prevalence and treatment. J Bone Joint Surg Am. 1997;79(1):65-8. PMID 9010187
    • Castilla EE, da Graca Dutra M, Lugarinho da Fonseca R, Paz JE. Hand and foot postaxial polydactyly: two different traits. Am J Med Genet. 1997;73(1):48-54. PMID 9375922

  3. 3. An associated syndrome is considerably more frequent with type A (well-formed) than with type B (rudimentary) ulnar polydactyly.

    True

    In the multicentre Congenital Upper Limb Difference (CoULD) registry of 334 patients, 21% of those with type A polydactyly had an associated syndrome, compared with 2% of those with type B. The authors recommend genetic consultation for children with type A ulnar polydactyly.

    • McQuillan T, Antonellis H, Wall L, Steinman S, Wang A, Bjorklund K, et al.. Predictors of Syndromic Association in Ulnar Polydactyly: Analysis of a Multicenter Congenital Hand Differences Registry in the United States. J Hand Surg Am. 2026;51(3):292-300. PMID 40377505

  4. 4. In type A ulnar polydactyly, the extra digit most often arises at the level of the metacarpophalangeal joint.

    True

    Pritsch's radiographic review of 49 patients allocated 64 of 67 type A deformities to five morphological subtypes, and the type originating from the metacarpophalangeal joint was the most common. Contralateral hand or foot polydactyly was frequent in these patients.

    • Pritsch T, Ezaki M, Mills J, Oishi SN. Type A ulnar polydactyly of the hand: a classification system and clinical series. J Hand Surg Am. 2013;38(3):453-8. PMID 23428187

  5. 5. Pooled data show that suture ligation of type B ulnar polydactyly has a complication rate similar to that of surgical excision.

    False

    Samarendra's systematic review of 15 studies found complications after 22% of ligation procedures against 1% after surgical removal, whether excision was done in clinic or in theatre (odds ratio 6.89). An earlier review described residual remnants and neuromas after ligation. The included studies were at high risk of bias, and parent-reported satisfaction was high with every treatment.

    • Samarendra H, Wade RG, Glanvill L, Wormald J, Jain A. Primary treatment of type B post-axial ulnar polydactyly: A systematic review and meta-analysis. JPRAS Open. 2022;34:21-33. PMID 36120500
    • Chopan M, Sayadi L, Chim H, Buchanan PJ. To Tie or Not to Tie: A Systematic Review of Postaxial Polydactyly and Outcomes of Suture Ligation Versus Surgical Excision. Hand (N Y). 2020;15(3):303-310. PMID 30417703