Limb-Length Discrepancy evaluation

Prepared by:Dr. Abdullah K. Ghafour2nd year IBFMS trainee

Supervised by: Dr. Ali Abdulnabi Alwan

Definition and epidemiology: • Differences between the lengths of the upper and/or lower arms

and the upper and/or lower legs.

• Except in extreme cases, arm length differences cause little or no problem in how the arms function.• the majority of individuals (up to two thirds ) have some degree of limb inequality .• The average discrepancy less than 1.1 cm can easily compensate.

Symptoms :

• The short leg gait is awkward

• increases energy expenditure because of the excessive vertical rise and fall of the pelvis

• back pain from long-standing significant discrepancies. • Compensatory scoliosis and decreased spinal mobility.

Types of LLD:

I. Structural or Anatomic type: due to a difference in the actual length of the tibia or femur.

• Congenital– Hemihypertrophy– Dysplasias– PFFD– DDH– unilateral club foot

• post-trauma • post-surgery

proximal femoral focal deficiency

unilateral club foot

Types of LLD:

II. Functional type: is due to asymmetrical foot or limb function .

• hip flexion or adduction contractures• flexion or hyperextension deformities of the knee or ankle• pelvic obliquity• genu varum and genu valgum

Types of LLD:III. Environmental type: is caused by the unevenness created by walking or running on crowned road surfaces, banked running tracks or along the beach.

Another Classification is McCaw and Bates (1991):o LLD has been classified according to the magnitude of the

inequality, generally expressed in cm or mm, and described as ;

Mild Less than 3 cm Moderate 3-6 cm Severe More than 6 cm

Etiology of Undergrowth• Congenital limb deficiency :

– Congenital femoral deficiency, – congenital fibular deficiency, – tibial hemimelia

• Asymmetrical neurological disorders: – Hemiplegic CP – poliomyelitis – Hemimyelomeningocele

• Traumatic causes: – malunion– growth plate arrest

Etiology of Undergrowth

• Hemiatrophy: - Idiopathic- Russel-Silver syndrome.

• Other causes: – infection, tumor– post-irradiation– Blount’s disease– LCPD– unilateral clubfoot– congenital pseudarthrosis of the tibia

Etiology of Overgrowth• Post-traumatic overgrowth:

– femur shaft fracture – tibia shaft fracture

• Soft tissue overgrowth syndrome: – Gigantism with neurofibromatosis– Klippel-Treunaunay syndrome– Beckwith-Wiedemann syndrome– Proteus syndrome

• Chronic inflammatory arthritis – Rheumatoid Arthritis

• Idiopathic hemihypertrophy.

Clinical assessment

• History:– Congenital or acquired?– Trauma / infection?– Progressive / static?– Onset and mode of deformity?– Any Syndrome associated features?

Clinical assessment• Examination:– Gait – Lower limb;

o Determine which segment is short?o Is it too long or too short?o Foot examo Exclude fixed deformities(knee and foot)o Muscle wasting?

– Spine;o Scoliosis (fixed or mobile)?

– Upper limb– face

Clinical assessment• Examination:– Wood block test

• Check the knee fully extended• ASIS level and Check spine• block testing is considered the best initial screening method

– Galeazzi (Allis) test

Clinical assessment

• Examination:– tape measurement• measure from the ASIS to the medial malleolus (true

length)• measure from the umbilicus to the medial malleolus (apparent length)

Investigations

• Standing radiographs• Teleroentgenogram• Orthoroentgenogram• CT–scannogram

Investigations

• Standing radiographso Block up shorter leg

Investigations

• Teleroentgenogram:o Single exposure and single cassetteo Disadvantage: magnification error

Length of x-ray shadow

Investigations

• Orthoroentgenogram:o single cassette is usedo 3 exposure center (hip, knee and ankle)o Disadvantage: only see the joint

Investigations

• CT–scannogramo most accurate diagnostic test with contractures

Investigations : Skeletal Age

1. Greulich- Pyle Atlas – X-ray Left hand (non dominant)– correlated with Green- Anderson table – less accurate < 6 Y– improved accuracy by focusing on hand bones rather than carpal bones

2. Tanner- Whitehouse Atlas – more refined – 20 landmarks graded Lt Hand – more accurate

Prediction Methods in LLD

I. Rule of thumb Westh and Menelaus (1981)o Main use is to time growth arrest

II. Growth remaining Anderson and Green (1963)o Determine the length of the long leg at maturityo Calculate the future growth of the long leg o Calculate % inhibition of shorter lego Calculate the future increase in discrepancy

III. Straight line Moseley (1978)o Graphical representation of Green and Anderson method

IV. Paley Multiplier Method (2000)o take LLD for boy or girl o multiplier for chronological or skeletal age o predicts LLD at maturity

Guidelines for Management

Discrepancy Management(CM)<2 No treatment or shoe lift

2-5 Growth Modulation

5-12.5 Consider bone-lengthening

>12.5 Combinations of above or amputation

Management of LLD:

• Shoe lift:o Patient who do not wish or are not appropriate for surgery. o Lift higher than 5 cm poorly tolerated.o Not good for bare foot

Management of LLD:• Growth Modulation:• Epiphysiodesis: (kill the growth plate)

• Very low morbidity and complication rate. • Slowing growth rate of long leg and allowing short leg to catch up• Suitable for sufficient data to enable a confident prediction of discrepancy at maturity.

• Eight Plates (squeeze the growth plate)

Management of LLD:

• Shortening operation: o Mature patient o Tibia< 4cm, Femur< 5cm o Neurovascular complication is higher in tibia, fasciotomy is advisable.

Management of LLD:• Limb lengthening operation:

o used to replace missing bones and/or to straighten deformed bones. o Can be performed on both children and adults with limb length

discrepancies (< 6cms) and angular deformities due to birth defects, injuries or diseases.

o Device for gradual lengthening Unilateral fixator Circular ring fixator (Ilizarov, Taylor spatial frame )

o Combined internal and external fixation (Lengthening over IM Nailing)

o totally implantable lengthening device Albizzia nail ISKD(inter medullary skeletal kinetic device) Fitbone

Management of LLD:

• Prosthetic fitting:Significant discrepancies:

o deformed functionally o useless feet o discrepancies greater than 15-20cmo femoral length less than 50%o Fibular hemimelia with unstable ankle o PFFD

A/K prosthesis or BK prosthesis with Van –Nes rotation plasty

Management of LLD:

• Amputation:o Significant length discrepancyo Severe fixed deformitieso Poor underlying bone quality for lengtheningo Dysfunctional/ painful limb

Klippel Tenaunay Syndrome

References:

• Robert M. Kliegman, Bonita F. Stanton, [2016]Nelson TEXTBOOK of PEDIATRICS, 20th ed. by Elsevier, Inc. Canada.

• Albert J. Pomeranz, Svapna Sabnis, [2016] PEDIATRIC DECISION-MAKING STRATEGIES, SECOND EDITION, 2nd ed. An Imprint of Elsevier , Tennessee, USA.

• Solomon L., Warwick D. , Nayagam S.,[2010] Apley’s System of Orthopaedics and Fractures, 9th ed. Hodderarnold comp.,London, UK.

• Miller M. , Thompson S. , Hart J. ,[2012] REVIEW OF ORTHOPAEDICS [PDF], 6th ed. by Saunders, an imprint of Elsevier Inc. , Philadelphia, USA.

• Canale S. , Beaty J. , [2007] Campbell’s Operative Orthopaedics [PDF], 11th ed. By Mosby, An Imprint of Elsevier , Tennessee, USA.

• Jay R. Lieberman, MD. , [2009] AAOS Comprehensive Orthopaedic Review,2nd ed. American Academy of Orthopaedic Surgeons, USA.

• L. Ombregt, [2013] A System of Orthopaedic Medicine, 3rd ed. Elsevier Ltd. China.

Questions