limb deformity Flashcards
what is adolescent Blount’s disease?
a progressive pathological genu varum
how will you assess the deformity?
long leg alignment views
Leg length discrepancy
- causes
-
Causes
- true - congenital and acquired
- apparent
TRUE
Congenital:
- Hip - DDH, coxa vara
- Longitudinal deficiencies - PFFD, tib/ fib hemimelia
- Foot/ ankle - unilateral club foot
- hemihypertrophy (beckwith-wiedemann syndrome) or hemiatrophy
Acquired
- Inflammatory - JIA (overgrowth)
- neuromuscular - polio, spinal dysraphism
- traumatic - physeal fracture or diaphyseal fracture (shortening/ overgrowth)
- Infection - septic OA (physis injury) or diaphyseal OM - bone hyperaemia
- radiotherapy - physeal damage
- tumour - haemangioma, neurofibroma
APPARENT
- flexion adduction contractures
- fixed pelvic obliquity
- scoliosis
- hip contractures - CP
leg length discrepancy assessment
Assessment
Clinical:
- GAIT - short leg gait (shorter stance and push off) and circumduction of long leg
- STANDING - assymetry, scoliosis (adams forward bend), contractures, blocks, cutaneous stigmata of spinal dysraphism (cafe au lait spots, hairy patches) and scars
- LYING:
- contractures
- true leg length - ASIS to med mal
- apparent leg length - umbilicus to med mal
- galeazzi - tibial or femoral shortening
- bryants triangle - supra or infra trochanteric
Radiological:
- long leg alignment views - teleroentgenogram - children under 3ft
- CT scannogram - most accurate - no magn errors
LLD calculations
- Paley’s multipler method - most accurate - diff multipliers for age and cause
- other methods - but don’t take into consideration variability in growth rate
- Arithmitic method - menelaus rule of thumb
Menelaus method
Makes the following assumptions:
- girls stop growing at 14 and boys at 16
- Most growth from knee - (15mm/year) 9mm distal femur/ 6mm prox tibia
- 3mm prox femur and distal tib
- diseased leg is static
- last 2yr growth - epiphysiodesis timing
- total growth discrepancy = current LLD + (annual LLD x no. years)
Bone age
Tanner whitehouse method - compares radius/ ulnar and short bones to reference charts
leg length discrepancy principles of management
Principles of treatment:
- assess child to determine cause of the deficiency
- treat cause if possible
- determine predicted LLD - paleys multi method and tanner for bone age
- reconstruction vs salvage
Reconstruction
< 2cm - shoe raise
2-5cm - epiphysiodesis of longer limb
>5cm - lengthening procedure
Salvage
- amputation/ prosthetics
- >15cm
Epiphysiodesis
- temporary - 8-plates or staples
- permanent - perc drilling - physeal arrest
Lengthening
- distraction osteogenesis with circular frame
- corticotomy - drill/ osteotome
- distraction - start >5days - 1mm per day
- DDH -address acetabular dysplasia 1st to stop hip subluxing
- fib hemi - span knee to stop sublux/ dislocation
- complications - infection, metalwork, poor regeneration or pre consolidation, NV injury, joint sublux/ dislocate
Coxa vara
* definition
* causes
* clinical features
* management
Definition
* localised bone dysplasia with a varus neck angle <110 deg due to a defect in the inferomedial femoral neck ossification
Causes
* congenital - skeletal dysplasias.- unilateral
* idiopathic - infantile
* acquired:
1. Trauma
1. perthes
1. SCFE
1. metabolic disorders - rickets
Clinical features
- Gait - painless limp is unilateral (normal stance) or waddling gait if bilateral (1/3rd cases)
- prominent GT
- positive trendelenberg test and gait
- LLD of 2cm in unilateral
- decreased internal rotation - decreased anteversion or true retroversion
Management
Based on hilgenreiner’s epiphyseal angle (bwn hilgenreiner’s line and femoral capital physis) normal = 20 deg
<45deg - corrects spontaneously
45-60 = observe - uncertain outcome
>60 = progresses - surgery
Surgery
- aim of treatment = correct the deformity by restoring the neck-shaft angle to 140deg
- intertrochanteric corrective valgus osteotomy
what is the rotational profile?
- Foot-progression angle - gait - normal -5 to 20 deg
- Hip rotation - assesses femoral version -
- Thigh-foot angle - tibial torsion
- Heel bisecting line - metatarsus adductus
Hip rotation
- normal = internal (IR <70deg)/ external rotation supine (ER=20 deg)
- Anteversion = IR>70deg and ER<20deg
Thigh-foot angle
- angle bwn thigh line and bisecting resting foot
- normal 10-20deg ER
Bleck -heel bisecting line
-normal = 1/2 webspace
- mild = 3rd toe
- moderate = 3/4 webspace
- severe = 4/5 webspace
Intoeing causes and management
Main causes:
- metatarsus adductus - 0-1yrs
- internal tibial torsion - 1-3yrs
- femoral anteversion - 3-6yrs
Metatarsus adductus
- forefoot adduction
- complex and skew foot = midfoot lat deviation and hindfoot valgus (skew only)
-Active correction to midline = no treatment
- passive correction to midline = stretching
- rigid = casting
- resistant to non-op = operative - medial column lengthening (cuneiform opening wedge) or lateral column shortening (cuboid closing wedge)
**Internal Tibial Torsion **
- normal = 5 deg IR in infants and 10 deg ER in 8yrs
- normally resolves
- Operative
1. 6-8yrs with >15deg IR
2. supramalleolar osteotomy
Femoral anteversion
- common in girls
- W sign
- resolve by 10yrs
- Residual ER <10 deg at 10yrs = intertrochanteric derotation osteotomy
Tibial bowing
- Anterolateral
- Anteromedial
- posteromedial bowing
Anterolateral bowing
- definition
- treatment
Anterolateral
* congenital bowing of the tibia with apex anterolateral
* 50% NF1 - only 10% NF1 patients
* Tibia hemimelia
* associated with pseudoarthrosis
crawford classification
1. canal preserved and cortical thickening - non op - might not fracture
2. thin canal - brace, total contact orthosis or surgery
3. cystic - risk of fracture - early fixation
4. frank pseudoarthrosis - worse prognosis - non-union- excise segment, graft and growing rod or frame
Factors guiding treatment
- presence of fracture
- age when fracture occurs
Non-op
Ambulant and bowing only - to prevent fractures
- check for NF1
- brace in a clam-shell cast
- patella-tendon bearing orthosis
- total contact cast
Operative
- reconstruction
- salvage
Reconstruction
Bowing + fracture/ pseudoarthrosis
1. resect pseudoarthrosis
2. free fibular bone graft
3. Charnley Williams Rod - antegrade through resection site and retrograde through heel
<4yrs: extend to calcaneus
5-10yrs: extend to talus
older free ankle
Salvage
- multiple failed procedures, leg length discrepancy or angular deformity
- syme or boyd amputation
Neurofibromatosis
definition
types
diagnosis
manifestation
Definition
Autosomal disorder of the neural crest
- mutation of NF-1 gene for neurofibromin protein on chromosome 17
- negatively affects ras signalling pathway
Types
- NF-1 - most common
- NF-2 - vestibular schwannomas
- NF-3 - segmental - only a single body segment affected
Diagnosis
based on 2 of the following
skin
- 6 cafe au lait spots - pigmented/ smooth (>5mm prepubertal or >15mm pubertal)
- axillary/ inguinal freckling
bone
- cortical thinning +/- pseudoarthrosis
- sphenoid dysplasia
eyes
- optic glioma
- lirsh nodules
tumours
>2 neurofibromas or 1 plexifibroma - risk of malignant transformation to neurofibrosacroma
1st degree relative
Manifestations
- Leg - bowing or hemihypertrophy
- spine - scoliosis (dystrophic/non-dystrophic), kyphosis
- hemihypertrophy
- increased risk of wilms tumours
Anteromedial bowing - fibular hemimelia
- clinical features
- management
Fibular Hemimelia
* Shortening or absent fibular
* deficiency SHH gene
Features
- PFFD
- coxa vara
- acetabular dysplasia
- hypoplastic lateral femoral condyle
- deficient ACL
- AM tibial bowing - deficient fibular
- ball and socket ankle joint
- tarsal coalition
- abscence lateral rays
- LLD
Management
Depends on:
- function and stability of foot
- LLD
Options:
Reconstruction
- small LLD - shoe raise/ bracing
- LLD <5cm or 10% shortening - contralateral epiphysiodesis*
- LLD <10% - lengthening *
- LLD 10-13% - lengthening and epiphysiodesis *
- * must have a stable plantagrade foot *
Salvage
- non-functional foot and ankle
- large LLD >30%
- unable to cope with multiple operations
- syme or boyd amputations
Posteromedial bowing
Posteromedial
* physiological - packaging
* linked to calcaneovalgus
* apex of deformity is distal tibia
* correct 5-7yr
* treatment - occassional stretching
* 3-4mm shortening
