Leg Length Discrepancy

Congenitally Short Femur



20 - 30 % LLD




Intact femur radiographically +

- foot at contralateral mid-tibial level

- cruciate ligament deficiency

- coxa vara

- hypoplastic lateral femoral condyle with resulting valgus knee

- sclerosed lateral cortex


Amount of femoral shortening is variable patient to patient


Shapiro Type 1 growth disturbance

- i.e. LLD increases with time





Genu valgum

Fat thigh

High riding patella


Foot held externally rotated




Hypoplastic femur

Coxa vara

Lateral sclerosis


2 groups


Simple femur hypoplasia


Femoral hypoplasia with coxa vara




Align early then lengthen in primary school years


1. Realignment may involve


Coxa vara

- proximal femoral valgising osteotomy


Valgus knee

- Supracondylar osteotomy / guided growth 8 plates


2. Lengthen tibia and femur


Caution for dislocated knee

- ACL deficient


3. Contralateral epiphysiodesis








Fibula Hemimelia



Deficiency of bony elements on lateral side of lower limb

- characterised by hypoplastic or aplastic fibula





- abnormal foot



- normal foot




Most common congenital deformity of long bones

- M:F   2:1


May be associated with PFFD



- tibial hemimelia can be inherited







- PFFD with type C / severe

- always slightly short femur



- cruciate deficiency

- hypoplastic LFC / valgus knee



- anteromedial bowing



- equino-valgus / ball and socket

- tarsal coalition



- small limb / foot

- absent lateral ray(s)

- lateral tarsal bones fused or absent


UL deficiency


Classification Coventry


Type 1:  Short or partial proximal absence unilaterally


1A:  Stable ankle joint ± ball & socket joint

1B:  Unstable anklejoint / equinovalgus


Fibular Hemimelia


Type 2: Complete absence unilaterally

- tibia short & bowed anteromedially, dimple at apex

- associated with lateral ray deformity & coalitions


Type 3:  Bilateral

- severe

- associated with PFFD & upper limb deficiency




Fibular hemimelia / dysplasia is a spectrum

- child may have only gracile fibular and short leg in tibia and femur

- attributed to fibula hemimelia as no ACL, short femur etc

- can be pseudoarthrosis of tibia

- realise when tibia fractures and then doesn't heal


Management Issues


1.  Foot / ankle deformity




If less than 2 rays or unstable ankle

- cannot salvage

- symes / BKA


Indication for Syme's Amputation

- severe deficient foot that will not serve any useful purpose

- grossly unstable ankle

- associated tibial deficiency such that LLD & unstable AKJ preclude leg lengthening

- associated PFFD 


2.  LLD 


Usually > 5 inches

- can predict based on difference at presentation 

- can treat if have normal foot


Usual Options

- < 3cm shoe lift

- 3-5 epiphysiodesis

- 5-10 limb lengthening

- 10-16 limb lengthening + epiphysiodesis

- > 16 amputate




5cm at a time

Usually start when child 7-8, can understand reason for operations


3.  Tibial bowing


Least important

- usually corrects




Growth Plate Arrest




- most common

- SH 4

- high energy SH 2 / 1 i.e. distal femur




Thombotic / embolic


Ischaemia (arteritis)






1. Central

- tenting 

- slows longitudinal growth +/- angulation


2. Peripheral

- can lead to rapidly progressive angular deformity

- especially small bar


Distal radius premature lateral growth arrest


3. Linear

- especially SH4

- effect depends on site and size




To assess deformity (angular and LLD)




To accurately map size and position of bar




1.  Epiphysiolysis



- < 50% growth plate

- > 2 year growth

- healthy skin




Excision of bar and interposition graft (fat)

- excision with high speed burr



- via direct approach to growth plate



- more difficult

- via metaphyseal window (avoid damage to the perichondral ring)


2.  Epiphysiodesis 



- remove active part of growth plate

- prevent angular deformity



- use drill under II guidance

- 4.5 mm


3.  Osteotomy



- correct angulation post growth plate fusion / epiphysiodesis







Asymmetry between L and R side more than due to normal variation


Upper limb hemiatrophy




Difficult to determine because no precise definition


Difficult to differentiate hemihypertrophy from normal variation

- enlargement soft tissues & bones also



- 1/13 000 combined

- 1/86 000 non-syndromic


Non syndromic hemihypertrophy associated with 4% incidence tumours






Non-syndromic is sporadic


Clinical Features


Rarely apparent at birth

- thicker skin, more hair, accelerated bone age on involved side

- ipsilateral paired organs increased in size also




Non-syndromic hemihypertrophy


Inguinal hernias



- renal cysts

- cryptorchidism

- sponge kidney

- horseshoe kidney



- non-structural

- compensatory to pelvic obliquity


Syndromic hemihypertrophy


Associated with cutaneous and vascular lesions





- involvement of ipsilateral paired organs



- also divided as per extent of involvement


Classic hemi - UL & LL

Segmental - UL or LL

Facial - head and neck only

Crossed - opposite UL & LL




Normal population may differ up to 1-2 cm in length and circumference


Rush and Steiner 1946

- 1000 US army recruits

- 23% equal leg lengths

- 77% 0.75 cm

- 15% > 1 cm


1cm difference

- in adolescent within normal

- in infant in pathological range   (4.2%)


Hemiatrophy V's hemihypertrophy


Compare length of L and R tibia and femora with normal standards



- no association with tumours


Non-syndromic hemihypertrophy / Beckwith-Weidermann syndrome

- are at increased risk for intraabdominal tumors 


DDX of non-syndromic hemihypertrophy


1. Beckwith- Weidmann syndrome

2. NF

3. Klippel-Trenaunay-Weber syndrome

4. Proteus syndrome

5. Malignant tumours

6. Olliers

7. Fibrous dysplasia

8. Poliomyelitis

9. Spastic hemiplegia of CP

10. Russell-Silver synd (short, cafe-au-lait spots, clinodactaly, hemiATROPHY)

11. JCA or haemophilia (secondary to hyperaemia)

12. XRT

13. Conradi-Hunnerman (chondrodysplasia punctata)


(5 - 13 may have contra-lateral shortened limb)


50% of hemihypertrophy will have syndrome


Beckwith-Weidermann Syndrome




Pre / postnatal overgrowth, birth weight > 90 %

- neonatal hypoglycaemia

- macroglossia

- hemihypertrophy occurs in 13%


Predisposition for embryonal tumors (Wilms)




Genetic abnormality Chr 11 p15

- near gene for IGF -II

- AD transmission but most sporadic




Need abdominal US


BWS with hemihypertrophy c.f. BWS without hemihypertrophy 

- risk embryonal tumour

- 27 V's 9%




NF1 may have overgrowth digit or limb




Characteristed by Hemihypertrophy + vascular malformations


AV Malformation Arm



- varicose veins

- port-wine nevi

- cutaneous and subcutaneous capillary haemangiomas

- cavernous haemangiomas


Proteus Syndrome


Name after Greek god who could change shape


Vascular + lymphatic malformations + lipomas



- haemangiomas

- lipomas

- lymphangiomas

- macrocephaly

- hyperostosis skull

- overgrowth long bones



LLD Aetiology

A.  General Conditions


Hemi-hypertrophy or atrophy



Klippel-Trenaunay-Weber syndrome

Proteus syndrome

Beckwith-Weiderman syndrome

Russel-Silver syndrome (atrophy)


Skeletal dysplasia


Chondrodysplasia punctata

Ollier's / Maffuci's

Multiple hereditary exostoses


Fibrous dysplasia




Closed HI


Spina bifida


Spinal dysraphism / tumor / injury

Peripheral nerve injury


B.  Specific Regions


Tumour / trauma / infection / radiotherapy physis




- Coxa vara



- Perthe's

- Tom Smith arthritis / post septic arthritis



- congenitally short femur



- fibula hemimelia

- tibial hemimelia

- bowing





Effect of LLD


Initially thought gives pain in back and contralateral knee and hip

- this may be debatable


1.  Short leg gait

- increased energy expenditure is the only proven effect of LLD


2.  Back 

- pelvic tilt and secondary scoliosis

- initially compensatory

- can become fixed

- ? causes LBP - now thought no different from general population

- most children's spines adapt (not so with adults)

- up to 2 cm easily tolerated


3. Contralateral Hip 

- uncovering of hip on long leg side in stance

- AKA long leg arthropathy

- ? increased OA 

- no evidence 


4.  Contralateral Knee 

- ? increased knee pain in athletes




2° Proliferative Zone chondrogenesis


Proximal Femur

- 3mm / year

- 15% leg


Distal Femur

- 9mm  / year

- 37% leg

- 70% of femur


Proximal Tibia

- 6mm / year

- 28%

- 60% tibia


Distal Tibia

- 3mm / year

- 20%


Growth Cessation


14-15 Girls

16-17 Boys




LL vs Chronological Age

- steady growth occurs

- growth spurt in early adolescence


LL vs Skeletal Age 

- Green & Anderson curves

- Growth vs Skeletal age

- shows no growth spurt

- because growth spurt & maturation spurt occur together


Skeletal Age & Chronological Age

- maturation can occur at different rates

- if early, are tall early & stop growing early

- can have spurt where mature more than age

- pass through skeletal ages more quickly




Determine cause

Determine deformity




LLD Assessment & Quantification

Quantification of LLD




1. Teleroentgenogram

- single exposure both legs

- long film with ruler

- Parallax errors


2. Orthoroentgengram

- same long Xray

- separate exposures hip, knee & AJ 

- eliminates parallax error

- problem artefact 


3. Scanogram

- similar separate exposures

- film moved between exposures

- smaller film

- multiple exposures


CT scan


Software measures distances 

- accurate to 0.2 mm

- legs must be in same position

- fast


Skeletal Age


1. Greulich- Pyle Atlas


Xray Left hand (non dominant)

- correlated with Green- Anderson table LL

- less accurate < 6

- improved accuracy by focusing on hand bones rather than carpal bones


2. Tanner- Whitehouse Atlas

- more refined

- 20 landmarks graded L Hand

- more accurate

- can't use as not correlated with LL


Prediction of Growth


Note that all methods have an inherent error of 12 months

- gives accuracy to 1.5 cm


Need > 3 measures 4/12 apart for all methods

- If inadequate data wait till older or wait till skeletally mature

- If acquired event caused LLD, can plot onto graph


1.  Menelaus "Rule-of-thumb" Method


Less accurate

- based on chronological age

- only valid from age ten

- convenient / easy / simple


Basic rules

- girls stop growing at 14 

- boys stop growing at 16

- distal femur 9 mm 

- proximal tibia 6 mm 

- distal tibia / proximal femur 3 mm 


Calculate how much growth lost from fusion of physis / Predict effect of epiphysiodesis

- Effect = Physis rate x years of growth Left


2.  Green & Anderson tables


Growth remaining method

- uses skeletal age

- requires graph

- estimates growth potential in distal femur and proximal tibia at various skeletal ages

- separate charts for girls and boys


3.  Moseley


Straight - Line Graph Method  

- uses Green & Anderson data

- applied to a chart


At least 3 measurements each time

1.  Length long leg

2.  Length short leg

3.  Skeletal age


Do so 3 times separated by 3-6 months

- accuracy improves with increased plotting


Plot the points for long and short leg on a vertical line for chronological age of either boy or girl

- create 2 lines for short and long leg over time

- line of best fit

- gives LLD at maturity at right of graph



- plot Long leg length on long leg line against skeletal age

- plot Short leg length on short leg line against skeletal age

- able with at least 3 measures to create line of best fit

- extend lines to maturity

- difference is LLD


Growth rate of each leg = slopes

- parallel or divergent 

- AKA static or progressive


Then use Menelaus rule of thumb to determine appropriate age for epiphysiodesis


4.  Paley multiplier


State of the art

- 2000

- take LLD for boy or girl

- multiplier for chronological or skeletal age

- predicts LLD at maturity


Patterns of LLD


Adds to difficulty

- static

- progressive

- regressive




1982 5 developmental patterns

- 75% types I and II


I Increasing

- LLD increases at constant rate

- hemihypertrophy / atrophy

- tibial pseudoarthrosis


II Increasing plateau

- similar early, but annual rate of increase diminishes thereafter

- Perthes


III  Plateau

- discrepancy increases, then stabilises

- fracture femur


- Polio


IV Increasing- decreasing

- similar to III, then late increase at end of growth


- hemihypertrophy


V Decreasing

- Initial increase, steady, then decrease


Progressive LLD


Progression Rate = Change LLD / Time


Final LLD

- add Current LLD to Prog Rate x Time to Skeletal maturity







LLD Examination

Four Physical Outcomes


1.  Symmetrical Stance & Level Pelvis 


A.  LL Equality

- components equal with no deformity


B.  Components equal with bilateral symmetrical deformity

- eg bilateral varus knees


2.  Symmetrical Stance with Oblique Pelvis 


Uncompensated LLD


3.  Asymmetrical Stance & Level Pelvis 


A. Fully Compensated LLD

- flexed contralateral knee 

- equinus ipsilateral ankle


B. Sagittal deformity with ipsilateral sagittal compensation

- FFD knee with equinus & hip flex OR

- fixed equinus with flex knee & hip OR

- FFD hip with equinus & flex knee


C.  Coronal deformity with contralateral coronal deformity

- valgus of knee & contralat varus of knee


4. Asymmetrical Stance with Oblique Pelvis 


A.  Partly compensated LLD

- partly flexed contralateral knee

- partly equinus of ipsilateral ankle


B. Coronal hip deformity with sagittal compensation

- fixed hip adduction with contralateral knee flexion / ipsilateral equinus

- fixed hip abduction with ipsilateral knee flexion / contralat equinus


C.  Sagittal deformity with coronal compensation

- FFD knee c ipsilateral hip abduction

- fixed equinus c ipsilateral hip ADD


Leg length Examination


1.  Look



- flexed knee


Signs hemihypertrophy

- NF
- haemangiomas / lipomas (Proteus, Klippel-Trenau-Weber, Beckwith)



- trauma, infection


2.  Gait




Compensate well 

- walk on toes short leg usually / equinus

- flexion long knee uncommon as energy++




Compensate less well

- walk with bilateral heel-toe gait

- vaults over long leg

- excess sagittal head motion


3.  Measure LLD

A.  Functional LLD

- on blocks

- heels flat, nil knee FFD (if able)

- correct pelvic tilt

- should correct scoliosis



- if can make pelvis stable

- ASIS equal

- blocks are a quantitative measure of functional LLD


B.  Apparent LLD


Lying on bed

- measure from xiphisternum to medial malleolus

- no correction for contractures


C. Real / True LLD


Must correct for deformity in coronal and sagittal plane



- hip adduction / abduction contracture

- hip FFD

- knee FFD



1.  Hip FFD

- pillow under both thighs

2.  Knee FFD

- pillow under both knees

3.  Hip adduction contracture won't correct to neutral

- measure each leg crossed over the other

4.  Hip abduction contracture won't correct to neutral

- place both legs in similar position


If there is a contracture, perform the above measures

- then meaure the intercalated segments

- from ASIS to medial joint line

- medial joint line to medial malleolus


4.  Identify site of shortening



- must not forget can have small foot / old calcaneal fracture / wasted buttock

- hips and knees flexed

- side by side

- look for tibial / femoral shortening


If shortening above knee, find out if shortened above greater trochanter

- i.e. hip deformity


Bryant's triangle

- line perpendicular to GT and ASIS

- distance between

- quantify in fingerbreadths


Nelaton's line

- line from ischial tuberosity to ASIS

- GT should be on or below line


Klisics line

- GT to ASIS

- should aim to umbilicus

- will be more parallel


5.  Other


Examine knee stability

- can have problems lengthening femur if ACL deficient

- i.e. fibula hemimelia






LLD Management



1. Equal leg lengths

- goal is mild to moderate isolated discrepancy


2. Unequal leg lengths

- goal with paralysis / equinus foot

- aim 1-2 cm short for clearance


3. Level Pelvis

- should use blocks to estimate functional correction


4. Vertical LS Spine

- vertical spine more important than level pelvis


5. Equalisation with Prosthesis

- goal with excessive LLD

- usually femur < 1/2 normal length or LLD >15cm




Correct coexisting deformity first

- can decrease discrepancy


May require correction of other problems first

- release of contractures

- correct angular deformity

- correct spinal deformity

- excision of bony bridge

- completion of partial arrest


Treatment guidelines by projected discrepancy


0 - 2 cm

- no treatment, heel raise


2- 6 cm

- shoe lift, epiphysiodesis

- maximum subtalar joint can take


6 - 15 cm 

- lengthening + epiphysiodesis


> 15 cm 

- amputation




Shoe Lift / sole raise


Good treatment if 2-5 cm

- aim is to improve gait



- > 5 cm ankle sprains

- joint unable to cope

- need patten boot (steel reinforcements of STJ)



- 0 - 1.5cm heel raise

- 1.5 - 5cm heel and sole raise

- 5 - 12cm patten and boot

- 12 - 20cm patten and AFO / prosthesis

- 20+cm prosthesis






Often treatment of choice

- low morbidity

- accurate

- can shorten at level of deformity




Operate on normal leg

- get loss of height & proportions




Anticipated LLD 2-6 cm


If > 6 cm LLD 

- excessive height loss

- knees at different level 


Phemister Technique


Create bony bridge

- medial & lateral approaches

- access window removed

- physis excised with curette


Percutaneous Technique 


Under II guidance

- percutaneous incision

- medial and lateral drilling into physis

- angle drill anterior and posterior

- entry points anterior, middle and posterior

- see white growth plate on drill




Continued longitudinal growth or angular deformity

- failure to eliminate growth plate


Femoral Shortening




Maximum 2 - 6 for reasons above


Consider if

- too old, insufficient growth remaining

- can't predict LLD and wait til maturity


Usually performed over a nail


Tibial Shortening



Max 3cm


Growth Stimulation


Stimulate physis by hypervascularity 2° irritative

- insert vicryl into growth plate

- moderate success


Leg Lengthening


See Limb Lengthening






Limb Lengthening



Concept of distraction osteogenesis


Popularised by Ilizarov in the Soviet Union 

- initially in the 1940's

- popularised in the 1980's

- also created the circular fixator



- low energy osteotomy

- attempt to minimise damage to blood supply and periosteum

- avoid use of saw

- minimise thermal necrosis



- gradual incremental distraction of a fracture callous after a latency period

- intramembranous ossification in zone of distraction

- type 1 collagen with osteoid laid on collagen




Maintains height & proportions

- Avoids operating on normal side





- steep learning curve

- complication rate 10 - 250%




General rules

- LLD 6-15 cm

- over 15 cm risks outweigh benefits

- < 20% limb

- 5cm in femur / 5 cm in tibia


Limitation is due to muscles / ligaments / nerves

- can repeat at staged procedures

- i.e. 5 cm per bone at any given time




Site of deformity best


Metaphyseal lengthening easiest

- large cancellous surface area

- thin cortex

- best blood supply




Mentally or medically unstable

- long and demanding process

- 12 months or more


Unstable joints


Associated neurology

- Weakness /  Insensate




1. Osteotomy & Frame / Nail

2. Latency Period

3. Distraction Period 

4. Consolidation Period


Maintaining blood supply via periosteum is the key


1A.  Osteotomy with Periosteal Preservation


Open Corticotomy


Drill-holes & closed osteoclasis / Di Bastiani


Used in the femur

- percutaneous skin incision

- multiple drill holes first to weaken bone

- osteotome to complete

- apply force to complete fracture


Usually stablise initially with temporary external fixator

- perform osteotomy

- insert nail / ISKD

- remove frame


Tibial technique with Gigli saw


Proximal corticotomy in metaphyseal bone

- below tibial tuberosity

- frame on initially to stabilise

- incision lateral crest tibia, elevate periosteum lateral tibia

- incision medial border tibia, elevate periosteum medial tibia

- pass artery clip between periosteum and bone on one side

- pass wire on other side, retrieve with clip

- pass suture, then pass gigli saw

- perform subperiosteal corticotomy, periosteum intact


Wagner Osteotomy


Contra-indicated now

- osteotomy and acute resection

- distraction

- bone grafting and plating

- superceded by lizarov techniques


1B. Devices


Need stable device or risk non-union with fibrocartilage


Uniplanar Device 

- Wagner, Orthofix

- simple

- no angular correction

- "Cantilever Loading"

- problems with pin loosing

- often necessary in femur



- multiplanar correction


IM nail  / ISKD


Self lengthening nail

- movement of leg induces lengthening mechanism

- maximum of 5 cm

- if only want 3 cm, lengthen 2cm before insertion



- all internal 

- no pin site complications

- easier for patient




Runaway nail 

- lengthens too quickly

- cause contractures and nerve injury

- nothing can be done about this

- incidence 5%


Jammed nail 

- take to theatre to unblock

- may have to debride callus if lengthening too slow


2.  Latency period 


Usually 1/52

- allow callus to form before distraction

- reduce latency period in child as may start to ossify

- increase latency period in diabetics / steroids


3.  Distraction Period


Rate / Regenerate


Optimum 1mm / day turning 4x / day

- balance premature union vs non union

- slower in adults / diabetics

- i.e. 2-3 x day


Stop if

- poor new bone formation

- nerve palsies

- joint subluxation

- joint contracture 


4.  Consolidation


1 month per cm or

Double the distraction period




Pin infection



- early oral antibiotics

- patient should have script at home

- take if pin site appears red or begins leaking fluid

- increase frequency of pin site cleaning



- tight well tensioned pins

- don't place pins throught muscle


Nerve  injury

- demyelinate if lengthen > 6%



- muscle elongates poorly

- max 1mm / day

- congenital LLD more susceptible than acquired



- T achilles contracture in tibia

- FFD / adduction femur

- knee FFD


Device failure

- broken pins, loss of position



- inadequate consolidation before device removal

- 10 - 15% incidence

- can result in loss of length or angular deformity


Premature Consolidation

- unable to distract

- break pins / wires


Poor regenerate

- inadequate latency period

- too rapid distraction

- poor blood supply


Joint subluxation

- ligamentous insufficiency


Delayed or non union

- constant observation


Bone growth impairment

- damage to physis

- likely secondary to pressure

- best if delayed until after skeletal maturity


Psychological Stress


Distraction Physiolysis



- tibial lengthening by distraction across physis

- similar results to metaphyseal lengthening



- need extra length in skeletally immature




Physeal injury risk


Chondrodiastasis if < 1mm / day




Tibial Hemimelia



Paraxial deficiency of skeletal elements on medial aspect of lower limb




Only skeletal deficiency with a documented familial occurrence 

- AD


1/ 1 000 000


Bilateral 30%




Leg short +++


Tibial Anterolateral Bowing


Foot fixed in severe varus

- can mimic CTEV

- sole facing perineum




- may be unstable

- no quads mechanism




Cleft hand

Reduplication of toes

CDH 20%




MRI to assess extent of proximal failure


1.  Unilateral Complete Type 1


No proximal tibial remnant

- usually foot abnormalities

- distal femur is hypoplastic & ossification delayed

- knee is featureless / unstable


Tibial Hemimelia Complete



- amputation early

- around 1 year before child gets attached to it


2.  Unilateral Partial Type II


Well developed proximal tibia & knee joint


Tibial Hemimelia Partial




A.  Knee

- proximal tibiofibular synostosis to prevent proximal migration

- fuse distal fibula to end of tibia

- then either symes or fuse fibula into calcaneus


B.  Ankle foot

- distal tibial deficiencies

- get equinovarus deformity similar to club foot

- tibiofibular synostosis

- then either keep foot if good or Symes


3.  Bilateral




A.  Bilateral through knee amputation


B.  Can try to make fibula into tibia and perform symes on one side

- Brown procedure

- need good quadriceps