gms | German Medical Science

14th Triennial Congress of the International Federation of Societies for Surgery of the Hand (IFSSH), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT)

17.06. - 21.06.2019, Berlin

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Thumb strength and manual ability in radial polydactyly at the interphalangeal and metacarpophalangeal joint level

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  • presenting/speaker Robert Dijkman - Erasmus MC, Rotterdam, Netherlands
  • Robert Leicher - Erasmus MC, Rotterdam, Netherlands
  • Ruud Selles - Erasmus MC, Rotterdam, Netherlands
  • Max Mann - Catholic Children's Hospital Wilhelmstift, Hamburg, Germany
  • Wiebke Hülsemann - Catholic Children's Hospital Wilhelmstift, Hamburg, Germany
  • Steven Hovius - Erasmus MC, Rotterdam, Netherlands
  • Christianne Van Nieuwenhoven - Erasmus MC, Rotterdam, Netherlands

International Federation of Societies for Surgery of the Hand. International Federation of Societies for Hand Therapy. 14th Triennial Congress of the International Federation of Societies for Surgery of the Hand (IFSSH), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT). Berlin, 17.-21.06.2019. Düsseldorf: German Medical Science GMS Publishing House; 2020. DocIFSSH19-1036

doi: 10.3205/19ifssh1371, urn:nbn:de:0183-19ifssh13718

Published: February 6, 2020

© 2020 Dijkman et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.

Outline

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Objectives/Interrogation: The aims of this study were to quantify strength impairment in radial polydactyly at the interphalangeal and metacarpophalangeal joint level (i.e., Wassel types II and IV), to assess which factors affect thumbs strength in radial polydactyly, and to evaluate the impact of thumb strength impairment on manual ability in radial polydactyly patients.

Methods: Postoperative thumb strength was measured in patients with unilateral radial polydactyly type II and IV using a pinch gauge dynamometer and the Rotterdam Intrinsic Hand Myometer ('RIHM'). Strength of the unaffected contralateral side was used as the reference. Radial polydactyly type, hand dominance, thenar hypoplasia, number of surgeries, sex, age at follow-up, duration of follow-up, instability, and thumb size were evaluated as potential determinants of thumb strength. Self-reported manual ability was measured using the ABILHAND-kids questionnaire.

Results and Conclusions: Eighty patients were included in this study, with a mean follow-up of 9.4 years. Thumb strength was 86% - 94% of the unaffected contralateral thumb in all measurements. Strength impairment was influenced by hand dominance, thumb size, and number of surgeries. Thumbs of radial polydactyly patients with an affected dominant hand were 10% - 29% stronger on average, compared to patients with an affected non-dominant hand, with exception of metacarpophalangeal flexion strength. Increased thumb size was positively correlated with pinch strengths, whereas increased number of surgeries showed a negative correlation. Forty-three (54%) patients attained the maximum score in the ABILHAND-kids questionnaire. While there was no correlation between relative thumb strength and manual ability, age at follow-up and duration of follow-up were positively correlated to manual ability.

The relatively small but statistically significant strength impairment of radial polydactyly patients does not impair their perceived manual ability. Strength is better in radial polydactyly cases with an affected dominant hand and in cases with relatively larger thumbs. An increase in number of revision surgeries is associated with greater strength impairment.