This document discusses the surgical management of duplicated thumbs. It begins by classifying duplicated thumbs and noting their prevalence. Type IV duplications, which involve joint deviation, are the most common. The document outlines factors that affect reconstruction surgery like the Wassel classification type and degree of deviation. The surgical principles aim for a functional thumb with adequate structure, stability, motion, alignment, and tendon function. The document then describes the retrospective study of 29 patients at Red Cross Children's Hospital between 2003-2008 who underwent thumb duplication surgery. It analyzes outcomes based on Wassel type and surgery performed, noting that stability at the thumb joints is essential for function and excision with ligament reconstruction yields good functional and cosmetic results.

1. Surgical Management Of
the Duplicated Thumb
Dr Steve Carter
Congenital Hand Surgery
Red Cross War Memorial Childrens Hospital

2. Radial Polydactyly
• Group 3 Duplication disorder
• Genetically most occur sporadically
• Occasionally AD
• Males > females , Right > Left
• Associated syndromes and anomalies

3. Thumb Duplication
• Synonymous with pre-axial or radial
polydactyly
• Accounts for 6-7% of all congenital hand
defects
• Incidence 0.08-1.4 per 1000 live births
• More frequent in Blacks and Asians than
in Caucasians

4. Wassel’s Classification
(1969)

5. Factors that effect surgical
reconstruction
• Wassel Type
• Deviation Particularly type 4
• Joint Stability
• Function
• Duplicate size

6. Surgical Principles
Goal is a functional thumb not
necessarily normal thumb
1. Adequate skeletal and soft tissue bulk
2. Joint stability
3. Joint motion
4. Thumb alignment
5. Tendon and muscle function
6. Cosmesis

7. Surgical Principles
5 step approach
• Central wedge zig zag incision
• Joint reconstruction in original deviated
position
• Osteotomies for alignment
• Tendon and muscle relocation
• Widen first web

8. Surgery
• Two Broad groups Wassel 1 to 3 and 4 to
7
Bilhaut Cloquet

9. Surgery

10. Surgery

11. Surgery

12. Surgery

13. Surgery

14. Surgery

15. Aim and Method
• A retrospective audit of the patients with
thumb duplications treated at Red Cross
Children’s hospital between 2003 and
2008
• A recall and re-examination of the patients
to determine their cosmetic and functional
outcomes based on the type of operation
performed

16. Patient Demographics
• 29 patients, 35 thumb
duplications
• 22 coloured, 5 black
and 2 white
• Male : Female of 2 : 1
• Left = Right

17. Distribution of Wassel
types
Wassel
Type
Number
thumbs
%
I 1 3%
II 9 26%
III 2 6%
IV 16 46%
V 1 3%
VI 2 8%
VII 3 6%
Total 35
I
3%
II
26%
III
8%
V
3%
VI
6%
VII
9%
IV
46%

18. Surgical Demographics
• Mean age at primary surgery was 21
months
• 85% had the radial thumb excised
• Mean post operative follow up 13 months
(2 weeks - 9 years)

19. Discussion
• Despite our average age at surgery being
21 months, this didn’t seem to affect the
outcome (ideally 12-18 months surgery)
• Kanavel’s statement in 1932 that “ablation
of one of the thumbs requires no ingenuity
and creates no problem“ is incorrect
• Simple excision high rate of complications
if joint involvement

20. Discussion
• Overall functional results were good
• Patients who had residual deviation were
not markedly functionally impaired
• Cosmesis questionable….despite high
patient and parent satisfaction
– Scarring was prominent in most patients
despite varying the incision between linear
and non-linear at the glabrous-dorsal skin
interface

21. Conclusions
• Stability at the IPJ and MCP is essential for
functional outcome
• Priority for a good functional and cosmetic
outcome is excision and collateral ligament
reconstruction
• Judicious use of osteotomies does not seem to
improve outcome
• We only do osteotomies if the presurgery
deviation at the affected level is >35o