2 Outline Congenital vs. Acquired Limb Morphogenesis Terminology and ClassificationTransverse DeficienciesLongitudinal DeficienciesAcquired Amputations
3 Congenital & Acquired deficiencies John angel with severe Femur fibula ulna syndrome, Vanessa Smith with severe meningococcal sepsis
4 Aetiology Congenital : Genetic Vascular Intrauterine amputation Maternal factorsAcquired:MeningococcalBurnsTraumaVascular malformationsTumourUsually the cause of congenital limb deficiency is unknown.congenitalGenetic: isolated or part of a multi-system syndrome or medical condition (e.g. Holt-Oram syndrome – hand heart syndrome)Current research suggests that many congenital anomalies have a genetic basis. Even when birth defects occur without a family history, DNA analysis may provide evidence of spontaneous genetic changeVascular: The type and severity of a vascular disruption depends on the gestational timing, the location of the involved vessel, the degree of tissue damage, and the adherence between tissues or organs.One of the major conditions with a vascular aetiology is amniotic band disruption syndromeIntrauterine amputation with or without amniotic bands causes about 10% of deficiencies seenMaternal factors (diabetes, factor V Leiden deficiency)Historically Thalidomide – proven to cause limb deficiency in children when mothers took it when pregnantSome acquiredFocal neonatalMeningococcalBurnsTraumaVascular malformationsTumour
5 Congenital Acquired No sense of loss Nothing new to adjust to Prosthesis as an aidFamily adjustment issuesProfound sense of lossPeriod of readjustmentHow well they adjust affects acceptance of prosthetic limbs
6 Limb Bud developmentKey genes involved in growth and patterning of the limb budsFormation involves numerous genes, the actions of which are interlinkedLimb bud development begins 4th weekKey genes involved in growth and patterning of the limb buds & development of the extremitiesFormation of a limb involves numerous genes, the role of which often concerns predominantly one particular aspect of the limb, but the actions of which are interlinkedLimb development begins during the fourth week along the flank of the embryo in predetermined regions, these are opposite cervicothoracic and lumbosacral segments
7 Limb MorphogenesisThickening of lateral plate mesoderm signals the overlying ectoderm to thicken and form a ridgeApical ectodermal ridge (AER) controls proximal-distal limbLimb develops in a proximal-distal directionInitiation of growth involves thickening of lateral plate mesoderm that, in turn, signals the overlying ectoderm to thicken and form a ridge over the tip of the limb bud.This apical ectodermal ridge (AER) controls proximal-distal limb growth by keeping the mesenchyme cells beneath it in a rapidly proliferating state, i.e. progress zone.As mesoderm cells move away from this progress zone, they cease proliferating and begin to differentiate.Thus the limb develops in a proximal-distal direction from the limb girdle to the digits.
8 Limb Morphogenesis(A) Limb begins with buds that form in mesoderm along the flank of the embryo.Growth of the UL precedes that of the LL by 1 to 2 daysAs the buds extend distally during the sixth week, the terminal portion flattens to form the hand and foot plates complete with digital rays(B) weeks: digits are present and the limbs have rotated to their normal position(C) 12 weeks: Cartilage first appears in proximal segments and ossification centres are present in the long bones
9 Congenital Limb Deficiencies About 1 : 5-10,000 birthsMay have complex genetics - important for geneticist to see family.In most cases cause unknown, low recurrence riskAbout 1 : 5-10,000 birthsMay have complex genetics - important for geneticist to see familyMuch of the research has been completed on the fruit fly, the mouse and the chick.There has been progress in the understanding of the role different genes play in limb development, but large gaps still existIn most cases cause unknown, low recurrence risk
10 Congenital Limb Deficiencies Most defects occur in period of limb morphogenesisWeeks 4-8 of gestation most critical timeSensitive period peaks 5th and 6th weeksMost defects occur in period of limb morphogenesis, when cells and tissues are rapidly proliferating and differentiatingWeeks 4-8 of gestation most critical timeThe limb’s sensitive period reaches a peak during the fifth and sixth weeks after fertilization – often prior to mother being aware she is pregnant
11 Upper and Lower Limb buds rotated at 7 weeks but digits not separated Final separation of the digits depends on additional cell death in the webbed area between each digitUpper and Lower Limb buds rotated at 7 weeks but digits not separated
13 Terminology and Classification ISO Classification 1989 is the accepted international standardTransverselimb developed normally to a particular level beyond which no skeletal elements existLongitudinalReduction or absence of an element/s within the long axis. There may be normal distal skeletal elements. Name the bones affectedPartial / TotalThe International Organisation for Standardisation (ISO) has accepted this as the international standard (8548-1:1989), it is restricted to skeletal deficiencies, where the majority of such cases are due to failure of formation of parts.The deficiencies are described on the basis of anatomic and radiologic characteristics only. No attempt is made to classify in terms of embryology, aetiology, or epidemiology.TransverseThe limb has developed normally to a particular level beyond which no skeletal elements exist, although there may be digital buds.LongitudinalThere is a reduction or absence of an element or elements within the long axis of the limb, and in this case there may be normal skeletal elements distal to the affected bone or bones.To describe such a deficiencyName the bones affected in a proximo distal sequence by using the name as a noun. Any bone not named is present and of normal form.State whether each affected bone is totally or partially absent.In the case of partial deficiencies, the approximate fraction and the position of the absent part may be stated.Standard :1989
15 Further Terminology Amelia: complete absence of the limbs Hemimelia: absence of some portion of the limbAdactyly: absence of fingersAchiera: absence of a handApodia: absence of a foot
16 Conversion Amputation is never applicable in the Upper Limb Paediatric deficiencies are often mixed and need to be considered in very functional terms :ShorteningUnstableTerminal lossConversion Amputation is never applicable in the Upper LimbPaediatric deficiencies are often mixed and need to be considered in very functional terms :Shortening : can it be lengthened?Unstable: stabilize with surgery, orthotics, prosthetics?Terminal loss : should there be a “ conversion amputation”?For children with congenital anomalies other than transverse deformity, surgical conversion of the limb to allow eventual prosthetic fitting often provides the most positive long term outcome.Each child would require separate assessment, but in general longitudinal absence of the fibula (complete) will requires a symes amputation.Longitudinal absence of the tibia (complete) will generally require knee disarticulation
17 Transverse Deficiencies The limb has developed normally to a particular level beyond which no skeletal elements exist, although there may be digital budsAetiology: Vascular disruption, Failure of formation, Constriction/ Amnionic Bands
18 Vascular Disruption may account for some transverse terminal losses It is thought that premature vascular insufficiency results in a failure of normal mesodermal proliferation, thus not allowing full limb formationVascular Disruption
20 Constriction Rings/ Amnionic Bands The other major cause of transverse limb deficiencies is early amnion rupture with disruption of limb growth.Strands of amnion become entangled around limbsFingers and toes are most often involved.Deep bands can cause distal oedema, nerve injury and impede growth.Amputation of digits or more proximal limb can also occur.Surgery for amnion disruption involves elective release and z-plasty of the bands
22 PFFDProfoundly short femur with bulbous thigh segment lying in external rotation & flexionflexed knee with cruciate insufficiencyfoot at level of opposite knee or just belowmost unilateral> 60% associated absence of fibula / other skeletal abnormalityProximal Focal Femoral Deficiency (PFFD) or Congenital deficiency of the femur
24 Proximal Femoral Focal Deficiency (PFFD) Type Adefect between femoral head & shaft with spontaneous restoration during growthType Bpersistent discontinuity between hip joint & femurType Cfemoral head never ossifies / dysplastic acetabulumType Dcomplete absence of the femoral head and acetabulumISPO classification is longitudinal deficiency of the femur (partial, proximal)Radiograph shows failure of bone formation proximally - subtrochanteric pseudarthrosis to total absence of the proximal femur and acetabulum
25 PFFD Management options Lengthening of femurSurgical procedures to provide hip stability & bony continuitySyme amputation / removal of foot + fusion of knee joint & prosthesisVan Nes rotationplastynon standard prosthesesNeed to consider:Inequality in leg lengthMalrotationInadequate proximal musculatureInstability of the proximal jointsLengthening of femur - Ilizarov (if 60% length of contralateral femur)Surgical procedures to provide hip stability & bony continuitySyme amputation / removal of foot + fusion of knee joint + prosthesisVan Nes rotationplasty (length 50% or < of the contralateral femur)non standard prosthesesVan Nes rotationplastyIn this procedure the tumour is removed while the neurovascular bundle and distal portion of the tibia and foot are maintainedThe tibia and foot are rotated 180 degrees, then attached to the remaining proximal femur so that the ankle is at the hight of the contralateral kneeBenefits include have a functional “knee” joint, stable reconstruction, less energy consumption and potentially fewer future surgeriesMajor disadvantage is the appearance of the limb, especially for teenage girlsfor bilateral PFFD most functional without prosthesesImportant to differentiate from congenital short femur which has profoundly different functional potential and can be reconstructed. In congenital short femur the entire femur is abnormal rather than a proximal or focal defect.
28 Longitudinal Deficiency of Fibula Shortening and anterior bowing of tibiaabsence of lateral metatarsal raysequinvalgus foot deformitycruciate ligament deficiencyThere can be hypoplasia with a portion of the fibula present or complete absence of the fibulaClinical features depend on severity of the deformityShortening and anterior bowing of tibia, or it can be straightInvolvement of other tissues and can have a dimple over the bow of the tibiaabsence of lateral metatarsal raysequinvalgus foot deformitycruciate ligament deficiency and valgus of the kneePossible to diagnoses at 16 weeks US
29 Fibula Deficiency Management Options Extension prosthesisleg lengthening +/- ankle stabilisationconversion amputation through ankle & prosthetic restoration with supracondylar suspension for knee stabilityThe major goal in the treatment of fibula deficiency, whether partial or complete, is maximising function.This means you need to achieve a plantargrade functional foot and appropriate length equalisationSome children may only need a shoe lift whereas other will require surgical intervention.Extension prosthesis – may have problems with cosmesis, especially in teenagersleg lengthening +/- ankle stabilizationconversion amputation through ankle & prosthetic restoration with supracondylar suspension for knee stability
30 Improving ankle stability and leg length discrepancy
35 Longitudinal Deficiency of Tibia Complete or partialIn complete absence:Short and relatively functionless legGross knee and ankle instabilityEquinovarus foot deformityNo potential for developmentCongenital anomalies of the tibia are relatively rare and can be complete or partialClinical findings vary depending on severity: Graded as type 1 to 4In complete absence: Type 1Severely short and relatively functionless legGross knee and ankle instabilityEquinovarus foot deformityNo potential for developmentType 1 is the most commonly occurring and most likely to be bilateral
37 Longitudinal Deficiency of Tibia Management:Through knee amputationAnkle disarticulationCentralisation of fibula / reconstructionFor patients with longitudinal deficiencies of the tibia, knee joint disarticulation is the typical treatment of choice, and patients generally function well with a prosthesisAmputation is optimally performed at about 12 months of age, although it is often deferred until the parents are convinced is and will be non functionalProsthetic fitting is appropriate when the patient is pulling to standOnly patients who are grade 4 (least severe) are candidates for attempted reconstruction of an ankle joint.
39 “Conversion” amputations Aim for a weight bearing stumpEnables better prosthesis useJoint disarticulation:Less risk of bony overgrowth as bones growMaximises the residuals growth potential as leaves both growth plates intact
40 Acquired Amputations Lawn mower motor vehicle farm machinery burns vascular catheterisationsLandminesTumours75% of acquired amputations are due to trauma25% due to other disease processesIn children less than 10 years old power lawn mower injury is the most frequent cause of amputation.Acquired amputations show a 2:1 male to female predominance.
41 Tumours May require amputation or various strategies for limb salvage The Van Nes Rotationplasty: distal femoral tumourMay require amputation or various strategies for limb salvageThe Van Nes Rotationplasty is used to salvage limb with a distal femoral tumourIn this procedure the tumour is removed while the neurovascular bundle and distal portion of the tibia and foot are maintainedThe tibia and foot are rotated 180 degrees, then attached to the remaining proximal femur so that the ankle is at the hight of the contralateral kneeBenefits include have a functional “knee” joint, stable reconstruction, less energy consumption and potentially fewer future surgeriesMajor disadvantage is the appearance of the limb, especially for teenage girls
42 Van Nes Rotationplasty Tumour removed while the neurovascular bundle and distal portion of the tibia and foot are maintainedTibia and foot are rotated 180 degrees, attached to the remaining proximal femurThe ankle is at the hight of the contralateral kneeBenefits: functional “knee” jointDisadvantage: appearance of the limbIn this procedure the tumour is removed while the neurovascular bundle and distal portion of the tibia and foot are maintainedThe tibia and foot are rotated 180 degrees, then attached to the remaining proximal femur so that the ankle is at the hight of the contralateral kneeBenefits include have a functional “knee” joint, stable reconstruction, less energy consumption and potentially fewer future surgeriesMajor disadvantage is the appearance of the limb, especially for teenage girls
43 Tumour removed while the neurovascular bundle and distal portion of the tibia and foot are maintainedTibia and foot are rotated 180 degrees, attached to the remaining proximal femurThe ankle is at the hight of the contralateral kneeBenefits: functional “knee” jointDisadvantage: appearance of the limb
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