Leg-length discrepancy

Leg-length discrepancy 

and Its management 

성균관의대 

삼성서울병원 

심종섭

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 

• Hemiatrophy: Idiopathic, Russel-Silver syndrome 

• Other causes: infection, tumor, post-irradiation, 

Blount’s disease, LCPD, unilateral clubfoot, 

congenital pseudarthrosis of the tibia


Trauma sequelae residual poliomyelitis osteochondromatosis

Etiology of Overgrowth 

• Post-traumatic overgrowth 

:femur shaft fracture, tibia shaft fracture 

• Soft tissue overgrowth syndrome 

:gigantism with neurofibromatosis, Klippel- 

Trenaunay syndrome, Beckwith-Wiedemann 

syndrome, Proteus syndrome 

• Idiopathic hemihypertrophy 

• Chronic inflammatory arthritis (ex. RA) 

Leg-length discrepancy

Idiopathic 

hemihypertrophy 

Klippel-Trenaunay 

syndrome 


Neurofibromatosis


Mechanism of compensation 

• The child with LLD usually compensates 

better than the adult. 

• The child can compensate for minor 

degrees of LLD by walking on the toes of 

shot leg. 

• The adult seldom compensate that 

manner- tend to heel-toe gait: vaulting gait 

& excessive pelvic motion and tilt.

Effect in Gait cycle 

The amplitude of vertical pelvic motion is increased by LLD. 


• Pelvic obliquity 

Hip - Effect 

• Relatively uncovered hip of long leg and 

increased coverage of the hip of the short 

leg. 

• Increased risk of DA of the long leg 


Effect in the Hip Joint 


Decreased in CE angle on the long leg side 

-- decreased in the load bearing area 

-- causes late degenerative arthritis.

Effect in the Spine 

• Low back pain and late degenerative arthritis: 

controversial 

• LLD- causes increased incidence of scoliosis 

• Severity of the problem 

-- related to the severity of LLD 

-- uncompensated or uncorrected 

-- onset of age 


Leg-length 

Patient Assessment-clinical 

1)Leg-length 

-Apparent length 

: from the umbilicus to the medial malleolus 

-Real length 

: from the ASIS to the medial malleolus 

-Wood block test 



Apparent length(UMD) Real length(SMD)

Wood block test 



Patient Assessment-clinical 

1) Leg-length 

2) Pelvic obliquity 

3) Angular deformity of the Joint 

4) Joint instability 



Radiological Assessment 


1)Teleroentgenogram 

- Single exposure of both leg on a long film 

- Reveals angular deformity 

- Error of magnification 

- Best technique for small children



2) Orthoradiograph 

- Exposures each joints individually 

- Avoiding errors of magnification 

- multiple exposure 




3) Scanogram 

- Moving film cassette 

- Avoid magnification 

- Cannot assess whole shape of leg 


Computed 

Scan Digital Radiograph Scanogram 


Estimation of skeletal maturity 

• Atlas 

• Sum of scores 

- Bone age - 

• Statistical combination of scores 


Bone age 

-Atlas- 

• Greulich and Pyle atlas (1959) 

- Rapid interpretation 


- Few changed in the hand during the critical time of 

puberty 

- 성장과정중 아이들마다 편차가 많다. 

- Interobserver error 

- Hand or Wrist 의 anomaly 있는 경우 측정이 어렵다.


Bone age 

-Scoring system- 

• Tanner-Whitehouse method (1975) 

- similar to Greulich and Pyle atlas 

: using hand and wrist X-ray 

: using computerized mathematical method 

(using 20 landmarks in the hand and wrist 

– scoring system) 

- more cumbersome, time consuming. 



• 1999 

- 5400명의 16세까지 어린이대상 

- TW2 방법 


Growth Calculation 

• The Arithmetic Method 

• The Growth Remaining Method 

• The Straight line Graph Method 

• The Multiplier method 


The Arithmetic Method 

• Simple 

-growth calculation- 

• Chronological Age 

• Inaccurate 


The Growth Remaining Method 

• Skeletal age 

• More accurate 



Green and Anderson growth remaining graph 

(Green & Anderson,1963)

The Straight line Graph Method 

• Skeletal age 

• Accurate 


• At least 3 check points needed 


The Multiplier method 

(Paley et al, 2000) 



• Based on Green and Anderson’s growth 

Graph 

• 한두번의 측정으로도 비교적 정확하게 향 

후 예상

Lowerlimb multiplier for boys and girls 


Multiplier method 

• Congenital Limb-Length Discrepancy 

∆m =∆ x M 

(∆: Current Limb-length discrepancy 

∆m: Limb discrepancy at skeletal maturity) 


Example) 현재 4cm 차이 있는 Congenital hemihypertrophy 

10세 남아의 최종 길이차이는 ? 

4 x 1.310 = 5.24 cm

• Developmental LLD 

∆m = ∆ + (IXG) 

I=1-(S-S’)/(L-L’) 

G=L(M-1) 

G= amount of growth remaining 

I=amount of growth inhibition 

L= current length of long limb 

L’=length of long limb as measured on previous radiographs 

Lm=length of femur or tibia at skeletal maturity 

M=multiplier 

S= current length of short limb 

S’=length of short limb as measured on previous radiographs 

∆ = current limb-length discrepancy 

∆m=limb length discrepancy at skeletal maturity 


• Right femur epiphyseal infection 을 앓은 

병력이 있는 10세 남아로 LLD를 주소로 내 

원하였다. 최종 예상 LLD는 ? 

8세 10세 

Femur length(cm) 

right 24 26 

left 26 29 


I =1-(26-24/29-26) = 1-2/3 = 0.33 

G= 29(1.310-1) = 29 x 0.310 = 8.99 

∆m = 3 + (0.33 x 8.99) = 3 + 2.97 = 5.97 cm

Time of Epiphysiodesis 

• Lm = L x M 

• Lε = Lm – Gε 

• Mε=Lm/Lε 

L= current length of long limb 

M=multiplier 

Lm= length of femur or tibia at skeletal maturity 

ε = desired correction following epiphysiodesis 

Gε=amount of femoral or tibial growth remaining at age of 

epiphysiodesis(Gε= ε/0.71 for femur and ε/0.57 for tibia) 

Lε=desired length of bone to undergo epiphysiodesis at time of 

epiphysiodesis 

Mε=multiplier at age of epiphysiodesis 


• Right distal femur epiphyseal infection 을 앓은 병력이 있는 

10세 남아로 LLD를 주소로 내원하였다. 가장 적절한 

epiphysiodesis 시기는 ? 

8세 10세 

Femur length(cm) 

right 24 26 

left 26 29 

Lm = L(29) X M(1.31) = 37.99 

Lε = Lm(37.99 ) – Gε(3/0.71) =37.99-4.22 = 33.77 

Mε=Lm(37.99)/Lε(33.77) =1.125 

multiplier chart 보면 

1.13 13세 

1.10 13세6개월 

따라서 가장 적절한 시기는 13세 1개월에 해당함. 


Treatment 

• General Principles 

0-2cm: No treatment 

2-6cm: Shoe lift,epiphyiodesis,shortening 

4-20cm: Lengthening 

>20cm: Prosthetic fitting 


Shoe lift 

• Patient who do not wish or are not 

appropriate for surgery. 

• Lift higher than 5 cm poorly tolerated. 


Prosthetic fitting 


• Significant discrepancies, deformed 

functionally useless feet 

• Discrepancies greater than 15-20cm and 

femoral length less than 50% 

• Fibular hemimelia with unstable ankle 

• PFFD: A/K prosthesis or BK prosthesis 

with Van Nes rotationplasty 

• Optimal age: syme amputation- end of 1yr 

Rotationplasty: 3 yr

Epiphysiodesis 

• 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. 

• Tibial epiphysiodesis should be accompanied by 

arrest of proximal fibular physis if tibial 

shortening is greater than 2.5cm.


• Phemister technique 

(JBJS,1933) 



• Blount (staple) technique (CORR,1949) 


12yr/female 1yr 2yr


• Percutaneous technique 

(Bowen R, et al,CORR,1984) 


Male/14yr (Sk.age), LLD: 2.5.cm 

Idiopathic hemihypertrophy 


Male/14yr 


Proximal tibia & Distal femur epiphysiodesis, Lt

Postop 3 yr 


Male/14yr 

Polyostotic fibrous dysplasia 

Tibial overgrowth, 2cm, right 


Postop 3 yr


• PETS(Percutaneous Epiphysiodesis using 

Transepiphyseal Screws) 

(Metaizeau JP, et al, JPO,1998) 


8-plated growth plate 


Stevens P, et al. JPO, 2006, 2008 


Problems of Epiphysiodesis 

• Undercorrection 

-- growth or angulation 

• Overcorrection 

-- growth or angulation 

• Rebound phenomenon (staples or screws) 

• Failure of growth restoration 

• Staple breakage or bending 


Shortening operation 

• Mature patient 

• Tibia< 4cm, Femur< 5cm 


• Neurovascular complication is higher in 

tibia, fasciotomy is advisable.

Neurofibromatosis, F/16 yr 


LLD, 4cm 

Genu valgum,Lt

Femur 

Corrective osteotomy 

1cm shortening 


Tibia 

3cm shortening

Preop Postop 2yr 


Growth stimulation 

• Circumferential release of periosteum 

• Foreign material implanted next to growth plate 

• Sympathectomy 

• Surgical constructed AV fistula 

• Periosteal stripping 


-- none has been successful enough to be 

clinically useful.

Limb lengthening operation 

• Codvilla(1905) – first described limb lengthening 

• Compere & Sofield (1936) 

• Anderson (1952) 

• Wagner (1978) 

• De Bastiani (1986) 

• Ilizarov (1989) 


• Transiliac 

One stage lengthening 

- Shortening < 3cm 

- Acetabular dysplasia 

• Femoral and Tibial 


Complication 

-Nerve injury 

-Artery occlusion 

-Reflex sympathetic dystrophy 

-Intraop. fracture 

-Joint stiffness or subluxation

Distraction Epiphysiolysis 

• Chonodrodiastasis (Gelbke,1951, De Bastiani,1986) 

- Separation of the epiphyseal plate 

- Immature patient 

- Risk of septic arthritis 

- Painful stiffness of the joint 

- Premature closure of the physis 


Gradual lengthening 

- Distraction Osteogenesis- 

• Ilizarov technique 

1) Corticotomy: preserve endosteal & periosteal 

blood supply 

2) Ilizarov Ring fixator: permit micro-axial motion 

3) Latency period: 7-14 days 

4) Proper rate & rhythm: 0.25mm x4 / day 

5) Encourage joint motion 




• Device for gradual lengthening 

- Unilateral fixator 

- Circular ring fixator (Ilizarov, Taylor spatial frame ) 

- Combined internal and external fixation 

(Lengthening over IM Nailing) 

(Lengthening with submscular plate) 

- Totally implantable lengthening device 

Albizzia nail 

ISKD 

Fitbone

Ring fixator 

Correction of complex deformity 

(as well as lengthening) 


Ilizarov Taylor spatial frame

Combined Internal and external fixation 

(Lengthening Over Nail) 


• Shorten the period of external fixation 

• Reducing the rate of regenerate bone fracture


Combined Internal and external fixation 

(submuscular plating after distraction osteogenesis) 

Oh, CW et al. JBJS Br 2009 :91: 1394-9 

Oh, CW et al. JPO B 2008 17: 265-9


- totally implantable lengthening device- 

ISKD Fitbone 



• Complication of gradual lengthening 

: 14%-134% 

Untoward Events - Paley D,CORR,1990 


- Problems - not requiring operative intervention to resolve 

- Obstacles - requiring operative intervention but without 

permanent sequelae 

- Complications - intraoperative injury or anything resulting 

in permanent sequelae

Thank you 

for your attention !

Thank you 

for your attention !

Leg-length discrepancy

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