Congenital Upper Limb Anomalies

Congenital Upper Limb AnomaliesDr O O WereCongenital deformities are attributable to faulty development and are present at birth, though they may not be recognised till later

Vary from severe malformations incompartible with life to minor structural abnormalities with no practical significanceCongenital anomalies affect 1-2% newborns with 10% with upper limb anomaliesAccurate diagnosis and communication to family requiredEmbryogenesis of upper limb between 4-8 week gestation guided by signalling centres within developing limb budAnomalies may be associated with systemic disorders, in isolation or in combination with other musculoskeletal problemsSignalling centresApical ectodermal ridgeZone of polarizing activityWingless-type( Wnt) signalling centreAbnormalities within 1 centre indirectly prohibit functioning of other 2 and affect limb formationApical ectodermal ridgeEctoderm layer guiding underlying mesoderm to differentiate to appropriate structuresLimb development in proximal to distal directionInterdigital necrosisZone of polarizing activityWithin posterior margin of limb budSignalling centre for anterior to posterior(radioulnar) limb developmentSignalling molecule for limb orietation sonic hedgehog protein

Wnt signalling centreDorsal ectodermSecrete factors that induce mesoderm to adopt dorsal characteristicsMediates development of dorsal-to-ventral axis configuration and alignment of the limb with dorsal orientation( dorsalization)CausesGeneticEnvironmentalCombined genetic and environmental: most congenital malformations in manGenetic include mutation of whole chromosome eg Downs syndrome and mutation of a small part of a chromosome or single gene eg achondroplasia

Environmental include dietetic, hormonal, chemical, physical, or infective9ClassificationI: Failure of formation of partsII: Failure of differentiation of partsIII: DuplicationIV: OvergrowthV: UndergrowthVI: Congenital constriction band syndromeVII: Generalized skeletal abnormalitiesInternational Federation of Societies for Surgery of the hand- 1976Numerous classifications based on embryology, teratologic sequencing, and/or anatomy

Each limb malformation classified according to the most predominant anomaly10

Failure of longitudinal formation- radial club hand

Failure of longitudinal formation- Cleft hand

Failure of differentiation- Syndactily

Congenital constriction band syndrome

Failure of transverse formation includes congenital amputations and phocomelia

Radial club hand results from radial deficiency with ulnar club hand from ulnar deficiency. Central ray deficiency results from failure of formation of central rays and includes split, cleft and lobster claw hand. It may be typical with central V-shaped cleft with 2 radia and 2 ulnar digits, with or without syndactyly. Atypical pattern is seen with absent 3 central rays leaving only a thumb and a small finger.

Syndactyly is incomplete if joining of digits is from a web space to a point proximal to fingertips and complete if joining digits from web space to fingertip. Simple syndactyly refers to only soft tissue bridging while complex syndactyly refers to both soft tissue and bone connections.15

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Constriction bandsType 1: mild transverse/oblique digital grooveType 2: deeper groove with abnormal distal partType 3: incomplete or complete syndactyly of distal part( acrosyndactyly)Type 4: Complete amputation distal to constrictionIncomplete type 1 treated by observationIf can cause vascular impairment, surgical release by multiple Z-plasty closureEntire release if shallowIf deep, only 1 side of digit released at each procedure to avoid vascular compromiseAcrosyndactyly separation initiated at 6/12Madelungs deformityAbnormal growth of volar and ulnar distal radial epiphysisUlnar and volar tilt of distal radial articular surfacePremature fusion of ulnar half of radial physisShort, bowed radiusShort ulnaWedging of carpus between distal radius and ulnaUlnar head enlarged and dorsally subluxatedApparent in late childhood/ early adolescenceDegrees of motion limitation and pain due to ulnocarpal impingementRxInitial splinting( Can provide complete and permanent relief)Surgery if persistent painRadial osteotomy plus ulna shortening osteotomyRadial osteotomy with distractionlengthening of the radiusFunctional development of childs handWell coordinated control of the grasp and pinch between thumb and fingers at end of 1st year1-3, refined coordination with bimanual dexterity and strength of grasp and pinchMaximal functional gain before child conforms to fixed pattern of activitiesMost reconstruction should be completed before schoolInitial assessmentDefinition and classification of abnormalityAssessment of severity of deformity with provision for deterioration with growthIf necessary, conservative treatment by splintage, stretching exercisesInform parents if later surgery neededClinical geneticist consult if necessarySurgeryAchievement of function and cosmesis( In order of priority)2-handed pattern superior to single handUnsightly abnormality may lead to psychological strain thus affecting functionNo operative intervention should compromise existing functionTimingDepends on specific anomalyUsually 6-18 monthsEarlier Rx for conditions that threaten limb viability e.g. constriction bandsGoals of reconstructive surgeryFunctional position of components of the handProvide good skin cover with adequate sensationSatisfactory power grip and precision pinchAll goals may not be achieved with a single procedure necessitating staged operations30Pitfalls in reconstructive surgeryDiversity of anomalies leads to difficulty in surgery( Every pt should be individualised)Unpredictable growth potential e.g. recurrence of webbing in syndactilyLack of cooperation from child complicates post operative rehabilitationRehabilitationTeam approachFunctional capability assessment by P.T./O.T.Parental care and encouragementCounselling by clinical psychologistChild prosthesisOnly realistic option in some anomalies e.g. transverse arrest at or above forearmTraining as early as 18/12 complexity in accordance with functional need

Chronological management planThumb anomaliesIsaac Newton In the absence of any other proof, the thumb alone would convince me of Gods existenceThumb hypoplasiaShort thumb: Doesnt reach PIPJ of index fingerAdducted thumbAbducted thumbPouce flottant: Short, unstable thumbmore distal and radial than normalAbsent thumb( Index pollicization)

Blauth classificationOther anomaliesCongenital trigger thumbCongenital clasped thumbAll neonates hold thumb in that position till 3/12 age

THUMB DUPLICATIONBoth radial and ulnar duplicates display some hypoplasia, but radial usually affected moreIntrinsic muscles innervated by ulnar nerve insert on ulnar duplicate while those by median nerve on radial duplicateDigits may be angulated and joints may be stiffM F

Many forms ranging from degrees of splitting to complete duplicationOccasionally only fleshy nubbins on radial borderDuplication alone usually unilateral and sporadicDuplication associated/w triphalangeal thumb usually AD

TreatmentSurgical treatment recommendedRecommended timeCombination of elements of both digitsFor unequal digits, excision of smaller digit with collateral ligament reconstructionCare to ensure normal articular contour of distal phalanx

Flatt recommends correction between 6-9 months44Individualised for more complex deformitiesFor type 4, least developed digit( usually radial duplicate) amputatedIntrinsic and extrinsic tendon transfers, with radial collateral ligament reconstructionOccasionally, osteotomy or growth plate arrest to improve alignment