Cleft (Claw) Hand

Historical Overview

• Cleft hand refers to a rare group of congenital hand abnormalities in which the central bony elements of the hand are missing. These deformities are characterized by a variable expression in a wide range of clinical phenotypes, but generally include a deficiency of the central ray with narrowing or syndactyly of the adjacent digits, creating a cleft in the center of the hand.^1-3
• The malformation that came to be known as cleft hand was first described by Isidore Geoffroy Saint-Hilaire in 1832, who assigned it the name ectrodactyly, which is still used by some clinicians today.⁴

Description

• Cleft hand is an uncommon hand malformation that involves a deficiency of the central ray and narrowing or syndactyly of the adjacent digits, which a clinician can identify when conducting a visual examination of the patient.

Pathophysiology

• The leading theory on the pathophysiology of cleft hand holds that at Carnegie stage 22, there is a wedge-shaped deficiency in the central part of the apical ectodermal ridge due to the loss of function of certain genes expressed in that region. This causes a failure in the normal process of formation of bones and/or interdigital spaces, which leads to cleft hand.^3,5
• All the abnormalities of cleft hand are believed to represent various degrees of severity of the same anomaly, suggesting the deformity may be due to an intrauterine vascular occlusion or insufficiency.⁶
• The depth of the palmar cleft depends upon the remaining metacarpal bones, with a shallow cleft when they are present and a deep cleft when absent.³
• Cleft hand can follow an autosomal dominant inheritance pattern, result from a spontaneous mutation, or stem from one of many associated syndromes, with inherited forms becoming more severe with each subsequent generation.²

Instructions

1. Obtain an accurate and complete patient history.
2. Observe and compare both patient’s hands, paying particularly close attention to the central digit and any associated abnormalities.
3. If an abnormality is noted, evaluate the grip strength, pinch strength, and passive and active range of motion of the remaining fingers in the affected hand.

Associated Conditions and Syndromes

• Symbrachydactyly
• Ectrodactyly-ectodermal dysplasia-cleft (EEC) syndrome
• Syndactyly
• Polydactyly
• Clinodactyly
• Bony fusion
• Anencephaly
• Cleft lip/cleft palate

Diagnostic Performance Characteristics

• Cleft hand has many variations, but the absence of the central portion of the hand is the main feature of the condition. Deficiency varies from absent long phalanges to absent individual finger, to monodactyly or even the absence of all digits.³
• Classifying cleft hand is difficult due to its heterogeneity, but one of the more commonly-used classification systems is as follows:
  • Type 1 (Typical)
    • Typical V-shaped clefting with presence of metacarpals
    • Typical crab clawing of the extreme fingers
    • Bilateral
    • Involves foot
    • Associated with other developmental defects
    • Familial inheritance is common
  • Type 2 (Atypical)
    • Also known as symbrachydactyly
    • Atypical cleft that is often U-shaped
    • Unilateral
    • Sporadic
    • Partial or complete absence of metacarpals
    • Hypoplastic thumb and little finger
    • Not associated with other syndromic manifestations
  • Type 3 (Nil-clefting)
    • All digits are absent¹

• A positive result occurs when the clinician observes any degree of deficiency of either central digit.

• A negative result occurs when no deficiencies are seen in the hand.

• Many authors have used terms such as “claw hand,” “lobster hand,” and “lobster claw hand” to describe this malformation in the past, but even though they may be descriptive terms, they are insulting to children and should no longer be used. The term “cleft hand” is therefore preferred, and when distinguishing it from symbrachydactyly, the adjective “typical” should be added. “Typical cleft hand” has consequently become the preferred nomenclature for decades by hand surgeons.⁴

1. Kundu, SK, Roy, H and Datta, A. A case of atypical cleft hand - reported with ontogenetic review. J Clin Diagn Res 2014;8(12):AD06-8. PMID: 25653934
2. Sullivan, MA and Adkinson, JM. Congenital Hand Differences. Plast Surg Nurs 2016;36(2):84-9. PMID: 27254240
3. Baba, AN, Bhat, YJ, Ahmed, SM, et al. Unilateral cleft hand with cleft foot. Int J Health Sci (Qassim) 2009;3(2):243-6. PMID: 21475543
4. Guero, S and Holder-Espinasse, M. Insights into the pathogenesis and treatment of split/hand foot malformation (cleft hand/foot). J Hand Surg Eur Vol 2019;44(1):80-87. PMID: 30380990
5. Beck, JD, Chang, B and Jones, NF. Over 20-year follow-up of Miura reconstruction of cleft hand. Hand (N Y) 2015;10(2):319-22. PMID: 26034452
6. Nair, SB, Mukundan, G, Thomas, R, et al. Ectrodactyly and prenatal diagnosis. J Obstet Gynaecol India 2011;61(6):683-5. PMID: 23204691