Polydactyly

Introduction

• History • Classification • Prevalence • Genetics • Embryology • Surgical

Reconstruction • Complex Polydactyly

History

• Bible • Kerchringii 1670 • Wellman (JAMA 1972)

– North American Indians • Multiple species

Classification

• Temtamy & McKusick (Birth Defects 1969) – Postaxial Polydactyly Types A & B – Preaxial Polydactyly

• Type 1: Thumb polydactyly • Type 2: Triphalangeal thumb polydactyly • Type 3: Index finger polydactyly • Type 4: Polysyndactyly

Classification• Graham & Ress (Hand Clinics 1998)

I. Polydactyly of the thumb II. Polydactyly of the triphalangeal digits

A. Index B. Polydactyly of the central rays C. Polydactyly of the ulnar hand and small digit

III. Complex Polydactyly A. Ulnar dimelia B. Pentadactyly C. Hyperphalangism

Radial Polydactyly

!Wassel

Classification

!!

The Growing Hand

Ulnar Polydactyly

• Temtamy & MuKusik – Type A – Type B

• Stelling (1968) & Tureck (1967) – Type I – rudimentary masses – Type II – subtotal duplication – Type III – complete extra digit

Central Polydactyly

Prevalence• Finley et al (South Med J 1994)

– 2.3:1000 white male – 0.6:1000 white female – 13.5:1000 black male – 11.1:1000 black female – 1:1000 Sweden

• Lamb et al (JHS 1982) – 2.4 – 27.2% all types

• Leung et al (JHS 1982) – 39.9% - most common

Prevalence

• Wassel – 13% among all congenital anomalies. !

• Mellin et al (Birth Defects, 1963) – 10.7:1000 African American – 1.6:1000 Caucasians

Prevalence

• Radial – Estimated 0.08 – 1.4 per 1000

• Tetmay & Mukisac (Birth Defects 1969) • Sesgin & Stark (Plast Reconstr Surg 1961)

– Common - American Indians & Asian – Males > Females – Right > Left

Prevalence• Ulnar

– Well formed – 1.24/1000 • Ruby & Goldberg (Ortho Clin North Am 1974)

– Type B – 1.88/1000 • 67% Black parents • 24% White parents • Male to female 1.33:1

– Watson & Hennrikus (JBJS 1997)

– 10:1 Blacks vs Non-black

Genetics• Radial

– Spontaneous mutations – Triphalangeal thumb – autosomal dominant

• Ulnar – Autosomal dominant – White children – associated syndromes

• Central – Autosomal dominant – Bilateral

Genetics• BMP 7 is expressed in the perichdrium of the

developing phalanges and finger tip ectoderm. • BMP-7 expressed at high levels in the

interdigital mesenchyme, which normally undergoes appotosis, loss of BMP-7 likely allows for survival of these cells. These survival cells can then give rise to an extra digit

• Gli-3 • (Daluiski, et al JHS, 2001)

Case report

• Preaxial Polydactyly EJHS 1997 – Bakker, et al

• Leeds family • High penetrated Autosomal dominant trait • Linkage analysis was performed on this

family material, and the phenotype described in this family is linked to chromosome 7q36.

number affected

• Preaxial extra ray(s) 15/15 • Thenar hypoplasia, non-opposable 8/15 • thumbs 7/15 • Opposable thumbs 2/15 • Unilateral septadactyly 2/15 • Unilateral TPT 15/15 • Preaxial polydactyly of the feet 1/15

The Growing Hand

The Growing Hand

Embryology

• Fetal limb – 26th day post • Final differentiation – 50th day • Interdigital spaces – 37th-47th • Stimulation of mesodermal tissue • Homeobox or Hox genes

Surgical Reconstruction

• Radial, Ulnar, Central • Classifications • Factors

– Timing – Goals

• Outcomes

Thumb Duplication• Timing – 1-2 yrs of age • Goals

– Adequate skeletal & soft tissue – Joint stability & motion – Thumb alignment – Tendon & muscle fxn – Cosmesis

Surgical Reconstruction

Thumb Duplication

• Preoperative Considerations – Function – Deviation – Joint Stability – Duplicate Size – Expectations

• “Two thumbs” • Additional procedures

Surgical Reconstruction

Distribution of Wassel Types of Thumb Duplication by Percentage

Surgical Reconstruction

Type Chicago (n=50)

Iowa (n=70)

Hong Kong (n=95)

Osaka (n=156)

Paris (n=50)

I 6 2 6 5 2II 12 15 17 16 18III 10 6 9 9 8IV 44 43 46 44 54V 4 10 12 14 0VI 6 4 3 3 4VII 18 20 6 9 16

Light (Hand Clinics 1992)

Wassel I & II

Type I Type II

Surgical Reconstruction

Wassel I & II

• Hypoplastic Duplicates – Combine bones – Reconstruct nail matrix

Surgical Reconstruction

Bilhout-Cloquet

Wassel I & II

• Large Duplicate(s) – Ulnar side – Preserve collateral lig – Centralize tendons – Osteotomy

Wassel I & II

Surgical Reconstruction

Surgical Reconstruction

Wassel I & II

Wassel III & IV

Surgical Reconstruction

Wassel III & IV

• Large Duplicate(s) – Ulnar side – Centralize tendons – Collateral lig

• Hypoplastic Duplicates – Central incision – Osteotomies – Soft tissues align – Joints are stiff

Surgical Reconstruction

Wassel V& VI

Surgical Reconstruction

Wassel V& VI

• Large Duplicate(s) – APB & FPB accessory – Detach musculature – Osteotomies – Four-flap Z-plasty

• Hypoplastic – Reconstruction of 3

bones & 3 Joints – On-top-plasty

Surgical Reconstruction

Wassel VII

• Triphalangeal Thumb – Several classifications – 1:25,000 live births – 2/3 bilateral – 50% thumb duplication – Reconstruction

Surgical Reconstruction

Central Polydactyly

• Index – Radial side – hypoplastic – Radial deviation – Interferes with thumb – Radial pinch

• Long & Ring – Failure of differentiation – Multiple procedures

Ulnar Polydactyly

• Type A – Level of duplication – Ulnar side ablated – Possible lig

reconstruction – Muscle transfers

Surgical Reconstruction

Surgical Reconstruction

Surgical Reconstruction

Ulnar Polydactyly

• Type B – Suture ligature? – “Nipple-like” bump

• Watson (JBJS 1997) – Revision amputation

Surgical Reconstruction

Complex Polydactylies

• Ulnar Dimelia – Mirror Hand Deformity – Absent thumb & radius – 7 digits – Pollicization, wrist

flexion, & tendon transfers

Complex Polydactylies

• Pentadactlyly – Five-fingered hand – MC distal physis – Triphalangeal digits – Develop web space – Pollicization

Outcomes

• Long-term Results of Surgical Treatment of Thumb Polydactyly Ogino et al (JHS 1994)

– Wassel Types III, V, VI, VII – Ulnar digit removed – Skill of surgeon