1. Paediatric Lower Limb Deficiencies
Natasha Hankin
March 2009

2. Outline Congenital vs. Acquired Limb Morphogenesis
Terminology and Classification
Transverse Deficiencies
Longitudinal Deficiencies
Acquired 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 factors
Acquired:
Meningococcal
Burns
Trauma
Vascular malformations
Tumour
Usually the cause of congenital limb deficiency is unknown.
congenital
Genetic: 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 change
Vascular: 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 syndrome
Intrauterine amputation with or without amniotic bands causes about 10% of deficiencies seen
Maternal factors (diabetes, factor V Leiden deficiency)
Historically Thalidomide – proven to cause limb deficiency in children when mothers took it when pregnant
Some acquired
Focal neonatal
Meningococcal
Burns
Trauma
Vascular malformations
Tumour

5. Congenital Acquired No sense of loss Nothing new to adjust to
Prosthesis as an aid
Family adjustment issues
Profound sense of loss
Period of readjustment
How well they adjust affects acceptance of prosthetic limbs

6. Limb Bud development
Key genes involved in growth and patterning of the limb buds
Formation involves numerous genes, the actions of which are interlinked
Limb bud development begins 4th week
Key genes involved in growth and patterning of the limb buds & development of the extremities
Formation 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 interlinked
Limb development begins during the fourth week along the flank of the embryo in predetermined regions, these are opposite cervicothoracic and lumbosacral segments

7. Limb Morphogenesis
Thickening of lateral plate mesoderm signals the overlying ectoderm to thicken and form a ridge
Apical ectodermal ridge (AER) controls proximal-distal limb
Limb develops in a proximal-distal direction
Initiation 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 days
As 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 births
May have complex genetics - important for geneticist to see family.
In most cases cause unknown, low recurrence risk
About 1 : 5-10,000 births
May have complex genetics - important for geneticist to see family
Much 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 exist
In most cases cause unknown, low recurrence risk

10. Congenital Limb Deficiencies
Most defects occur in period of limb morphogenesis
Weeks 4-8 of gestation most critical time
Sensitive period peaks 5th and 6th weeks
Most defects occur in period of limb morphogenesis, when cells and tissues are rapidly proliferating and differentiating
Weeks 4-8 of gestation most critical time
The 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 digit
Upper and Lower Limb buds rotated at 7 weeks but digits not separated

12. Upper limb total deficiency

13. Terminology and Classification
ISO Classification 1989 is the accepted international standard
Transverse
limb developed normally to a particular level beyond which no skeletal elements exist
Longitudinal
Reduction or absence of an element/s within the long axis. There may be normal distal skeletal elements. Name the bones affected
Partial / Total
The 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.
Transverse
The limb has developed normally to a particular level beyond which no skeletal elements exist, although there may be digital buds.
Longitudinal
There 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 deficiency
Name 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

14. An example:
What is in black is missing

15. Further Terminology Amelia: complete absence of the limbs
Hemimelia: absence of some portion of the limb
Adactyly: absence of fingers
Achiera: absence of a hand
Apodia: 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 :
Shortening
Unstable
Terminal loss
Conversion Amputation is never applicable in the Upper Limb
Paediatric 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 buds
Aetiology: 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 formation
Vascular Disruption

19. Stump is usually smooth

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 limbs
Fingers 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

21. Longitudinal Deficiencies
Proximal Focal Femoral Deficiency (PFFD)
Fibula Deficiency
Tibial Deficiency
Femur Fibula Ulna Syndrome
Partial foot (lateral ray deficiency)

22. PFFD
Profoundly short femur with bulbous thigh segment lying in external rotation & flexion
flexed knee with cruciate insufficiency
foot at level of opposite knee or just below
most unilateral
> 60% associated absence of fibula / other skeletal abnormality
Proximal Focal Femoral Deficiency (PFFD) or Congenital deficiency of the femur

23. PFFD

24. Proximal Femoral Focal Deficiency (PFFD)
Type A
defect between femoral head & shaft with spontaneous restoration during growth
Type B
persistent discontinuity between hip joint & femur
Type C
femoral head never ossifies / dysplastic acetabulum
Type D
complete absence of the femoral head and acetabulum
ISPO 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 femur
Surgical procedures to provide hip stability & bony continuity
Syme amputation / removal of foot + fusion of knee joint & prosthesis
Van Nes rotationplasty
non standard prostheses
Need to consider:
Inequality in leg length
Malrotation
Inadequate proximal musculature
Instability of the proximal joints
Lengthening of femur - Ilizarov (if 60% length of contralateral femur)
Surgical procedures to provide hip stability & bony continuity
Syme amputation / removal of foot + fusion of knee joint + prosthesis
Van Nes rotationplasty (length 50% or < of the contralateral femur)
non standard prostheses
Van Nes rotationplasty
In this procedure the tumour is removed while the neurovascular bundle and distal portion of the tibia and foot are maintained
The 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 knee
Benefits include have a functional “knee” joint, stable reconstruction, less energy consumption and potentially fewer future surgeries
Major disadvantage is the appearance of the limb, especially for teenage girls
for bilateral PFFD most functional without prostheses
Important 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.

27. Severe Femur – Fibula - Ulna

28. Longitudinal Deficiency of Fibula
Shortening and anterior bowing of tibia
absence of lateral metatarsal rays
equinvalgus foot deformity
cruciate ligament deficiency
There can be hypoplasia with a portion of the fibula present or complete absence of the fibula
Clinical features depend on severity of the deformity
Shortening and anterior bowing of tibia, or it can be straight
Involvement of other tissues and can have a dimple over the bow of the tibia
absence of lateral metatarsal rays
equinvalgus foot deformity
cruciate ligament deficiency and valgus of the knee
Possible to diagnoses at 16 weeks US

29. Fibula Deficiency Management Options
Extension prosthesis
leg lengthening +/- ankle stabilisation
conversion amputation through ankle & prosthetic restoration with supracondylar suspension for knee stability
The 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 equalisation
Some children may only need a shoe lift whereas other will require surgical intervention.
Extension prosthesis – may have problems with cosmesis, especially in teenagers
leg lengthening +/- ankle stabilization
conversion amputation through ankle & prosthetic restoration with supracondylar suspension for knee stability

30. Improving ankle stability and leg length discrepancy

32. Bilateral Longitudinal Fibula deficiency and complete
deficiency of the 5th ray of the foot

35. Longitudinal Deficiency of Tibia
Complete or partial
In complete absence:
Short and relatively functionless leg
Gross knee and ankle instability
Equinovarus foot deformity
No potential for development
Congenital anomalies of the tibia are relatively rare and can be complete or partial
Clinical findings vary depending on severity: Graded as type 1 to 4
In complete absence: Type 1
Severely short and relatively functionless leg
Gross knee and ankle instability
Equinovarus foot deformity
No potential for development
Type 1 is the most commonly occurring and most likely to be bilateral

37. Longitudinal Deficiency of Tibia
Management:
Through knee amputation
Ankle disarticulation
Centralisation of fibula / reconstruction
For patients with longitudinal deficiencies of the tibia, knee joint disarticulation is the typical treatment of choice, and patients generally function well with a prosthesis
Amputation is optimally performed at about 12 months of age, although it is often deferred until the parents are convinced is and will be non functional
Prosthetic fitting is appropriate when the patient is pulling to stand
Only patients who are grade 4 (least severe) are candidates for attempted reconstruction of an ankle joint.

39. “Conversion” amputations
Aim for a weight bearing stump
Enables better prosthesis use
Joint disarticulation:
Less risk of bony overgrowth as bones grow
Maximises the residuals growth potential as leaves both growth plates intact

40. Acquired Amputations Lawn mower motor vehicle farm machinery burns
vascular catheterisations
Landmines
Tumours
75% of acquired amputations are due to trauma
25% due to other disease processes
In 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 tumour
May require amputation or various strategies for limb salvage
The Van Nes Rotationplasty is used to salvage limb with a distal femoral tumour
In this procedure the tumour is removed while the neurovascular bundle and distal portion of the tibia and foot are maintained
The 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 knee
Benefits include have a functional “knee” joint, stable reconstruction, less energy consumption and potentially fewer future surgeries
Major 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 maintained
Tibia and foot are rotated 180 degrees, attached to the remaining proximal femur
The ankle is at the hight of the contralateral knee
Benefits: functional “knee” joint
Disadvantage: appearance of the limb
In this procedure the tumour is removed while the neurovascular bundle and distal portion of the tibia and foot are maintained
The 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 knee
Benefits include have a functional “knee” joint, stable reconstruction, less energy consumption and potentially fewer future surgeries
Major 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 maintained
Tibia and foot are rotated 180 degrees, attached to the remaining proximal femur
The ankle is at the hight of the contralateral knee
Benefits: functional “knee” joint
Disadvantage: appearance of the limb

44. Questions?