Polydactyly

Polydactyly

1. POLYDACTYLY

2. Embryology of Upper Limb The upper and lower limbs begin development in the 4th week of gestation. The limb buds are the precursor structures of the limbs. Their formation begins in the 4 th week.

3. The limb buds first appear on the ventrolateral body wall initially and extend ventrally . They consist of a central core of undifferentiated mesenchyme tipped with a layer of ectoderm - the apical ectodermal ridge (AER). Elongation occurs through proliferation of the underlying mesenchyme core

4. 1. AER – Apical Ectodermal ridge Acts as signaling center to guide underlying mesoderm to differentiate into appropriate structure It is essential for proximo-distal limb development It is responsible for interdigital necrosis ,which separates the webbed hand. ZPA - The zone of polarizing activity Signaling center for antero-posterior ( Radio Ulnar) limb development Responsible for limb orientation Dorsal Ectoderm – produce morphogenic protein controlled by wingless-type (Wnt) signaling center which is responsible for dorsalization of upper limb . ( Dorso -ventral axis ) All 3 function in coordination to ensure proper limb development.

5. 8 week after fertilization, embryogenesis is complete & all limb structures are present. – majority of congenital anomaly occurs during this period. Primary Ossification center are present in all long bones by 12 th week

6. Timeline : Onset of development of arm bud :27 days 4 th week Well developed arm bud: 28-30 days Elongation of arm bud: 34-36 days 5 th week Formation of hand paddle: 34-38 days Onset of finger separation 38-40 days full separation of fingers : 50-52 days 7 th week

7. Congenital anomalies affect 6 per 10000 of newborns Out of which 75% have Upper extremity abnormalities.

8. Classification of Congenital Anomalies of UL International federation of societies for surgery of the hand (IFSSH-1983) FAILURE OF FORMATION OF PARTS:(Arrest of development) transverse arrest : common levels are upper third of Forearm, wrist, metacarpal, phalangeal Longitudinal arrest : phocomelia , club hand, cleft hand FAILURE OF DIFFERENTIATION OF PARTS: Soft tissue involvement Skeletal involvement Ex. radio ulnar synostosis ,camptodactyly ,arthrogryposis DUPLICATION: polydactyly , mirror hand OVERGROWTH: macrodactyly UNDERGROWTH: thumb hypoplasia, madelungs deformity CONGENITAL CONSTRICTION BAND SYNDROME GENERALIZED ABNORMALITIES AND SYNDROME

9. Classification of Congenital Anomalies of UL International federation of societies for surgery of the hand (IFSSH-1983) FAILURE OF FORMATION OF PARTS:(Arrest of development) transverse arrest : common levels are upper third of Forearm, wrist, metacarpal, phalangeal Longitudinal arrest : phocomelia , club hand, cleft hand

10. Classification of Congenital Anomalies of UL International federation of societies for surgery of the hand (IFSSH-1983) FAILURE OF DIFFERENTIATION OF PARTS: Soft tissue involvement Skeletal involvement Ex. radio ulnar synostosis ,camptodactyly ,arthrogryposis

11. Classification of Congenital Anomalies of UL International federation of societies for surgery of the hand (IFSSH-1983) DUPLICATION: polydactyly, mirror hand OVERGROWTH: macrodactyly

12. Classification of Congenital Anomalies of UL International federation of societies for surgery of the hand (IFSSH-1983) UNDERGROWTH: thumb hypoplasia, madelung’s deformity CONGENITAL CONSTRICTION BAND SYNDROME GENERALIZED ABNORMALITIES AND SYNDROME

13. Polydactyly - Definition Polydactyly ( poly = more; dactylos = finger) refers to the disorder in which patients have more than five digits on at least one extremity

14. History Polydactylous hand and footprints have been found when studying rock art and petroglyphs , some dated 1000 AD. Polydactyly was first time referred in literature - in the Old Testament, (a battle in Gath) a giant had six fingers on each hand, and six toes on each foot. The term polydactyly is first described by Kerckring in 1670.

15. Genetics Inherited isolated dominant radial polydactyly and triphalangeal thumb - chromosome 7q36 – regulated by SHH protein. Isolated ulnar polydactyly an autosomal -dominant inheritance pattern with variable expression. Central polydactyly (ring finger duplication) combined with syndactyly has a familial inheritance pattern and has been linked to a gene mutation (HOXD13 gene) on chromosome 2.

16. Together with Syndactyly and Camptodactyly , it is the most common congenital upper extremity difference. The incidence can range from 2% to 30% when considering all types of Polydactylies . Polydactyly can occur in combinations / involve both hands (and / or) feet, Can be associated with syndactyly . Over 97 genetic syndromes have been associated with polydactyly .

17. Polydactyly Duplication of fingers It is of 3 types Pre axial > duplication of thumb more common in whites. Central > duplication of index, middle and ring fingers Post axial > duplication of small finger - most common in African

18. Ulnar polydactyly is 10 times more common in – African - Americans and 2 times more common in males. Ulnar polydactyly is mostly bilateral and can be associated with syndactyly and polydactyly of the feet . Syndromic association is more common in ulnar polydactyly . Radial polydactyly is more common in Asians. Radial polydactyly is mostly unilatera l. Central polydactyly is extremely rare in all published studies.

19. PREAXIAL POLYDACTYLY : THUMB DUPLICATION (BIFID THUMB) Epidemiology Most common duplication pattern in Whites and Asians 1 in 3,000 births Usually unilateral. Cause unknown. Sporadic, with systemic problems

20. Classification Wassel classification (most commonly used) – Based on Radiology Adapted from Wassel HD: The results of surgery for polydactyly of the thumb: a review, Clin Orthop Relat Res 125:175–193, 1969.

21. Classification Wassel classification Type I : Partial duplication of The distal phalanx and a common epiphysis Type II : Complete duplication including epiphysis of the distal phalanx. Type III : Duplication of distal phalanx and bifurcation of proximal phalanx. Type IV : Complete duplication of distal and proximal phalanx

22. Classification Wassel classification Type V : Complete duplication of distal and proximal phalanx with bifurcation of the metacarpal Type VI : Complete duplication of distal and proximal phalanx and metacarpal. Type VII : Variable degree of duplication with triphalangeal thumb Type IV is most common ( 50 %) . T ype VII (20 %). T ype II ( 1 2 %) .

23. Clinical Assesment Detailed Medical history and Family history. General physical examination – If the index to little finger is normal, with normal hand and finger creases, and a normal hypothenar region, the examination is concentrated on the radial side of the hand. Examination is performed from proximal to distal. Start with thenar musculature and con Wassel I and II, the thenar musculature is mostly normal in contrast to wassel type V, VI, and VII Hypermobility of involved joints vs Generalized ligamentous laxity .

24. Initial examination includes Observation of thumb usage, Palpation of the bony elements, Assessment of joint stability. Passive motion, Varus / Valgus stress testing of the joints, Palpation of tendons (especially flexor tendons), Observation of the skin crease

25. Look for creases both dorsally and palmarly . If creases are present, then an active movement in that particular joint can be expected. In most of these cases, the radial-sided thumb is hypoplastic and stiff, and the ulnar thumb is the better one . Little or absent passive motion at the bifurcation site of the minor thumb (most radial one) suggests an odd-numbered Wassel type I, III, or V . One of the duplicated elements is usually dominant and preferred for prehension . If polydactyly is situated at the CMCJ, the MCPJ in the best thumb can be near normal.

26. Several investigators have noted that the thumb is not truly duplicated. Neither component is as robust as a normal thumb . Each thumb is thinner than normal and has diminished mobility. The term split thumb seems more appropriate . Range of motion is typically less than in a normal IPJ. In an asymmetric duplication at the IPJ, the best-developed part usually moves better. In a newborn - it is often difficult to distinguish between intrinsic and extrinsic movements. In duplicated thumbs, the flexor tendon and extensor apparatus is usually less developed or absent in the more hypoplastic thumb .

27. The split parts may share bony elements, tendons, ligaments, joints, neurovascular structures, and nails. The nails are smaller and asymmetrical in most cases. Wassel type 1 & 2 – Widening of nail plate. The first web is nearly always normal in the distal duplications . In more proximal polydactylies , the first web can be narrower than the normal contralateral side.

28. A Typically there is some degree of hypoplasia of both duplicates and commonly radial duplicate is more Hypoplastic. There may be convergence or divergence of duplication Ulnar innervated intrinsic muscles to the thumb (adductor policies, deep head of fl exor polices brevis), typically insert on the ulnar most thumb duplicate

29. Median innervated intrinsic muscles to the thumb (abductor policies, superficial higad of the flexor pollicis brevis and opponens pollicis) insert on the radial most thumb duplicate Extrinsic flexor and extrinsic tendons may be duplicated and usually are eccentric. Collateral ligaments of the duplicated joints are shared Both radial and ulnar neurovascular bundle to the digits may be completely duplicated or may be shared with small separate branches that supply the individual digits.

30. C oncerns Cosmetic deformity – concern to both parents and child. Functional impairment - depending on the level of the duplication ( shaking hands, putting hands in pockets or narrow spaces, and wearing gloves).

31. PRE-AXIAL Treatment - goals Goals Of Treatment T o construct a thumb that is 80% of the size of the contralateral thumb R esect smaller thumb (usually radial) P reserve / reconstruct medial collateral structures in order to preserve pinch function R econstruction of all components typically done in one procedure Timing of surgery 12 - 18 months (prior to devolopment of Thumb index finger pinch)

32. S urgical exploration may reveal a cartilaginous connection that is not visualized by x-ray. This operative finding reclassifies a type II thumb to a type I and a type IV thumb to a type III. The surgeon needs to be aware of this possible surgical finding, which may alter the operative plan. The ideal reconstruction - aligns the thumb along a longitudinal axis, stabilizes the joints, balances the motor functions, provides an adequate nail plate without deformity, and restores sufficient thumb size. Reconstruction or preservation of the collateral ligaments is critical for duplications that arise from the joint surface ( Wassel II, IV, and VI).

33. CORRECTION OF TYPES I AND II BIFID THUMBS Common nail Asymmetric type I or II duplication with distinct components is treated by ablation of the smaller thumb, with transfer of the collateral ligament and centralization of the extensor tendon. The collateral ligament from the deleted component is elevated with an osteoperiosteal sleeve and attached via periosteal suture to the reconstructed thumb. A separate facet for the deleted component is removed with an osteotome , rongeur , or bone-biter to narrow the articular surface and properly align the joint with the retained component.

34. TYPES II

35. CORRECTION OF TYPES I AND II BIFID THUMBS Symmetric ( Wassel ) 1 & 2 - Bilhaut-Cloquet Technique technique involves removing central tissue and combining both digits into one outcomes approximately 20% have late deformity problems include stiffness, angular and size deformity, growth arrest, and nail deformities

36. CORRECTION OF TYPES I AND II BIFID THUMBS Bilhaut-Cloquet Technique

37. Modified Bilhaut – cloquet procedure ( Baek and collegues )

38. CORRECTION OF TYPES III To VI BIFID THUMBS LAMB, MARKS, AND BAYNE I ndications usually favored approach for type III and IV type V and VI usually require more complex transfer of intrinsics and collateral ligaments T echnique preserve skeleton and nail of one component and augment with soft tissue from other digit and ablation of lesser digit (radial digit most commonly)

39. CORRECTION OF TYPES III In a type III thumb, the entire physis and collateral ligament maybe preserved to maintain motion, prevent any chances of MCP joint instability, and avoid damage to the physis . The osteotomy is designed to preserve the entire proximal phalanx base, and an osteoperiosteal sleeve is not raised.

40. CORRECTION OF TYPES III To VI BIFID THUMBS Extraarticular malalignment may require corrective osteotomy to ensure longitudinal alignment of the thumb (closing wedge osteotomy ) to align the joint surfaces in a parallel manner. Tendon realignment is also necessary to centralize the tendons along the retained thumb. Any thenar intrinsic muscles that are attached to the deleted thumb are transferred to the retained thumb. Typically, the abductor pollicis brevis inserts into the radial thumb and must be detached with an osteoperiosteal sleeve along with the radial collateral ligament

41. TYPES IV

42. TYPES IV

43. TYPES IV

44. TYPES IV

45. Type 4

46. CORRECTION OF TYPE V & VI BIFID THUMBS Treatment of type V or VI duplication uses similar principles, with the added complexity of additional intrinsic reconstruction. In addition, the thumb/index finger web space may be narrowed . A concomitant “Z”- plasty or dorsal advancement transposition flap may be required.

47. CORRECTION OF TYPE VII BIFID THUMBS In a Wassell type VII duplication (complete duplication), the radial thumb should be removed . The remaining thumb may require web reconstruction and metacarpal osteotomy to complete the pollicization. If the retained component is triphalangeal - A joint reduction procedure with chondrodesis across the joint with the least motion will reduce the number of joints. This procedure can be done at the time of thumb reconstruction or as a second-stage procedure.

48. Triphalangeal Thumb with Radial polydactyly

49. Postoperative care The a long-arm thumb spica cast applied. The cast and Kirschner wire are removed 4 to 5 weeks after surgery. A shortarm thumb spica splint is fabricated, which is removed for therapy and gentle activities. The splint is discontinued 8 to 12 weeks after surgery.

50. Complications Small Reconstructed Thumb, Angulation , Joint Instability, Limited Motion, Scar Contracture Z- deformity of thumb

51. Outcomes The results vary with the degree and complexity of the thumb duplication. Satisfactory results are readily obtainable in type I, II, and IV duplications. Less satisfactory results are prevalent in types III, V, and VI and in triphalangeal thumbs. Nail deformities and IPJ stiffness are less common with Modified Bilhaut-cloquet method.

52. Secondary Procedures Possible secondary procedures, either or not in combination, can include: ■ Ligament reconstruction ■ Tenolysis ■ Tendon rebalancing ■ Opposition transfers (sometimes in the more proximal Wassel types) ■ Nail deformity correction ■ Osteotomy and alignment of articular surfaces ■ Neurolysis and neuroma treatment in adult patients ■ Arthrodesis of IPJ or MCPJ ■ Scar revision.

53. POSTAXIAL (ULNAR) POLYDACTYLY: Autosomal Dominant – variable penetrance pattern Duplication of the small finger It is the most common pattern of duplication in the black population sometimes indicative of an underlying syndrome (e.g., chondroectodermal dysplasia or Ellis–van Creveld syndrome)

54. C lassification Two-type classification - Temtamy and McKusick . Type A (Well devoloped ) comprises an extra little finger at the MCPJ, or more proximal including the CMCJ. The little finger can be hypoplastic or fully developed. Type B (Rudimentary / Pedunculated ) varies from a nubbin to an extra, non-functional little finger part on a pedicle.

55. B . Three types classification Type-1: Duplication of soft parts only Type -2: Partial duplication of the digit, including the osseous structures Type-3: Duplication of the ray including the metacarpal

56. The most common presentation is a small appendix on a skin pedicle with intact neurovascular bundle, attached at the ulnar border of the proximal phalanx, has mostly a small nail and thus a distal phalanx, and is non-functional. Sometimes two bones are present. If the extra little finger is more developed, the more common site of duplication is at the MCPJ . In these cases, the fifth metacarpal is broad. Depending on the extent of development and the attachment at the MCPJ, the extra little finger flexes and extends well. If the extra finger originates at the MCPJ, full flexion at the MCPJ might not be possible as the joint is not normally developed.

57. Full motion of the MCPJ of the normal fifth finger can be affected. Flexor tendons and extensor tendons are usually Y-shaped and asymmetrical, as in the duplicated thumb. The extra finger is usually abducted at the MCPJ and radially deviated at the PIPJ. The hypothenar muscles are attached at the ulnar side of the extra digit and palmarly at the broad MCPJ. If the extra little finger is at the base of the metacarpal or at the CMC, the joint of the finger is usually well developed. Physical examination of ulnar polydactyly depends on the development of the extra little finger.

58. POST-AXIAL Treatment - Surgical TYPE 1 : tie off in nursery or amputate before 1 year of age TYPE 2 & 3 operative Excision of the extra digit technique preserve radial digit preserve or reconstruct collateral ligaments from ulnar digit remnant preserve muscles

59. Outcomes In ulnar polydactyly , a small painful mass can remain following ligation or inadequate resection of the pedicle of the extra floating little finger.

60. CENTRAL POLYDACTYLY Usually associated with syndactyly . In central polydactyly , the second, third and/or fourth digit can be involved. Fully developed extra independent fingers are rare. In order of appearance, the most frequently affected is the ring finger, followed by the long finger, and ultimately the index finger. Frequently, the duplication of the fourth finger is partial and hidden by a syndactyly , typically to the third finger.

61. A number of varieties are possible because the duplication often is not confined to one finger. In addition to the bony deformity and aberrant growth plates, anomalies of the flexor and extensor tendons and neurovascular structures.

62. CENTRAL POLYDACTYLY

63. CENTRAL POLYDACTYLY

64. CENTRAL POLYDACTYLY Treatment – Don’t treat - if digit is fully formed with full motion and function. An isolated central polydactyly with limited motion is treated by resection of the ray. Synpolydactyly – Seperation of syndactyly and reduction of concealed polydactyly ( Combination of Resection and osteotomy + ligament reconstruction ) P erform early (1 yr ) to prevent angular growth deformities and imp rove motion

65. CENTRAL POLYDACTYLY Treatment – Central synpolydactyly with complicated connections may better be left untreated than separated into individual digits with limited motion and instability.

66. Type VII Wassel - Type 1 Mirror Hand ( Ulnar Dimelia )

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