Leg conditions Flashcards
Proximal femoral focal deficiency Hemihypperthrophy Leg length discrepancy
What is proximal femoral focal deficiency?
- A Congential defect of the proximal femur
- it is a spectrum of disease including
- Absent hip
- Cervical pseudoarthrosis- see pic
- Absent Femur
- Shortened Femur

What is the epidemiology of proximal femoral focal deficiency?
- Bilateral in 50% cases
- Rare autosomal Dominant form exists
- Associated with SONIC HEGDE- HOG GENE ( limb bud gene)

What is the pathophysiology of proximal femoral focal deficiency?
- Defect in the primary ossification centre ( cartilage anlage)
Name associated conditions of proximal femoral focal deficiency?
- Fibular Hemimelia- 50%
- ACL Deficiency
- Coxa Vara
- Knee contractures
Non orthopaedic manifestations
- Dysmorphic facies found in rare autosomal dominant type

What is the Classification system of proximal femoral focal deficiency?
- AITKEN
- Class A= Femoral head present, Acetabulum Normal
- Class B= Femoral head present, Acetabulum mildy dysplastic
- Class C= femoral head absent, Severly dysplastic acetabulum
- Class D= Absent Femoral head and acetabulum

What is seen at physical exam of a pt with proximal femoral focal deficiency?
- Severely shortened one or both legs
- Percentage of shortening remains constant with growth
- Short bulky thigh is flexed, abducted and externally rotated
- Normal feet - most common

What are the goals of tx in proximal femoral focal deficiency?
- Tx must be individualised to the pt based on
- Leg discrepancy
- Present of foot deformities
- Adequacy of Musculature
- proximal joint stability
What are the options for tx for proximal femoral focal deficiency?
-
Non operative
-
Observe
- with bilateral deficency
-
Extension Prothesis
- Less attractive option due to large proximal segement of prothesis
- assists patient when attempting to pull self up to stand
-
Observe
-
Operative
-
Limb lengthening with/without contralateral epiphysiodesis
- If predicted LLD of <20cm at maturity
- Stable hip and functional foot
- femoral length >50% of opposite side
- Femoral head present- Aitken A/B
- CI= unaddressed varus, proximal pseudoarthorosis, or acetbular dysplasia
-
Syme amputation and Knee fusion
- Hip stable ( aitkena/b) foot of affected side is proximal to knee joint- syme 10-14 mo, knee fusion 3-4 yrs= wear AK prothesis
- need for improved prosthetic fit, function and appearance
- prosthetic kness will not be below the level of contralteral knee at maturity
- ispislateral foot is at level of contralateral knee or more proximal
-
Femoral- pelvic fusion
- Unstable hip =aitken C/D- absent femoral head
-
VAN - NESS ROTATIONPLASTY
- ipsilateral foot at level of contralateral knee
- Ankle with >60% of motion
- Absent femoral head- aitken c/d
- 180 degree rotational turn thru femur
- ankle dorsiflexion becomes knee flexion
- allow use of BK prosthesis to improve gait and efficiency- seep pic
-
Amputation
- for femoral length <50% opposite side
- perserve as much length as possible
- amputate thru JOINT if possible in order to avoid overgrowth which can lead to diffcult prosthesis fitting
- Fit for prothesis UL 6 mon, LL 1 yr
-
Limb lengthening with/without contralateral epiphysiodesis

What is Hemihypertrophy?
- A condition of asymetric limb size
What are the most common causes of hemihypertrophy?
- Neurofibromatosis
- Idiopathic
- Beckwith- wiedemann syndrome
- associated with Wilm’s tumour- renal abnormaliites, do USS until 5 years
What is the tx of hemihypertrophy?
- Based on principles of leg length discrepancies
What are the common causes of limb length discrepancy?
-
Congential
- Hemihypertrophy
- Dysplasias
- Proximal femoral focal deficiency
- DDH
-
Paralytic conditions
- Spascitiy - cerebral palsy
- polio
-
Physis disruption
- Infection
- trauma
- Tumour
What is the epidemiology of LLD?
- 2cm LLD occurs in up to 2/3rd population
What are the associated conditions of LLD?
- Back pain
- increased prevalence of back pain
- Osteoarthritis
- Decreased coverage of femoral head on long leg side leads to OA 84% of time
- Structural scoliosis
- LLC increasea the incidence of structural scoliosis
- Inefficiency Gait
- Equinus Contracture
What is the classification of LLD?
- STATIC
- Malunion of femur/tibia
- PROGRESSIVE
- Physeal growth arrest
- congential
- absolute discrepancy increases
- proportion stats the same
What are the symptoms and signs of LLD?
- Usually asymptomatic
Signs
-
Block testing
- W pt standing add blocks under short leg until pelvis is level, then measure blocks to determine discrepancy
- Block testing is considered best initial screening method
-
Tape measurement
- Measure from ASIS to medial malleolus w tape
- evaluate for hip, knee, and ankle contractures
- effects apparent limb length
- hip adduction contracture= apparant shortening of adducted side
*
What imaging is useful in LLD?
- Scanography/HKA- see pic
- measure discrepancy with scanogram
- Bone hand films
- determine bone age
- CT Scanography
- Is most accurate diagnostic test with contractures of hip, knee or ankle

What are the LLD predictions?
- General assumptions
- growth continues until 14 yrs girls, 16 yrs boys
- Methods to predict LLD at maturitry
- Mosley charts- growth remaining
- estimation techique- arithmetic method
- assumes certain contribution from physis to longitudinal growth
- leg growth 23mm/year w most of that coming from knee (15mm/yr)
- proximal femur 3mm/year
- distal femur 9mm/yr
- proximal tibia 6mm/yr
- distal tibia 5mm/yr
- Can be tracked with
- Green- anderson tables
-
mosley straight line graph
- improves on green-anderson method by formatting data in graph form
- accounts for differences between skeletal and chronologic age
- Multipler method
What is the tx of LLD?
Non operative
- Shoe lift/observation
- if <2cm projected LLD at maturity
Operative
-
Shortening of long side via Epiphysiodesis of femur/tibia or both
- 2-5cm projected LLD
-
Limb lengthening of short side
- if projected >5cm LLD
- lengthening often combined with shortening proceedure epiphyiosdesis/osteotomy long side
-
Physeal bar exicision
- if bony bridge involves <50% physis
- at least 2 years of growth
*
What is the surgical technique of limb lengthening?
- Distraction osteogenesis- Ilizarov prinicples
-
initation
- perform osteotomy and plate fixator
- metaphyseal corticotomy to preserve medullary canal and blood supply
-
distraction
- wait 5-7 days then begin distraction
- distract 1mm per day
- follow distraction keep fixator on for as many days as you lengthened
- concurrent proceedure
- Some ream over a nail so ex-fix can be removed sooner
- lengthening often combined with a shortening proceedure- epiphysiodesis/ostectomy on long side
-
initation
What are the compilications of LLD?
-
Incomplete arrest/angular deformity
- open technique
- percutaneous technique
- Pin site infections
- Fractures
- Delayed union
- Premature ossification of lengthening
- Joint subluxation/dislocation