LIMB LENGTH DISCREPANCY

Dr. m. DehnokhalajiOrthopaedic surgeon

TUMS

• RADIOGRAPHIC ASSESSMENT OF

INEQUALITY

•Advantages •lower radiation exposure•greater accuracy,•less susceptibility to error if the patient is poorly positioned, •the ability to accommodate positioning difficulties econdary to joint contractures or the presence of external fixators.•specifically indicated when the patient has a knee flexion contracture or is in a circular external fixator .

• PREDICTION OF LEG LENGTH INEQUALITY IN THE

SKELETALLY IMMATURE CHILD

Anderson-Green-Messner Growth-Remaining Charts

Paley Multiplier Method

Menelaus Method

• growth cessation to age 16 for boys and age 14 for girls .

Moseley Straight-Line Graph

• Moseley in 1977 described a straight-line graph method for calculating the ultimate discrepancy in a skeletally immature child and determining the timing of long-leg epiphysiodesis to correct leg length inequality.

• The purpose of Moseley’s graph was to simplify and improve the accuracy of calculations intended to estimate the ultimate discrepancy in growing children by incorporating into the calculations skeletal maturation based on hand-wrist bone films, growth inhibition, and relative size.

1. Plot the long leg point.

The diagonal line representing the growth of the long leg is part of the graph. The long leg length should be plotted on that line at the appropriate length.

2. Draw the line for that assessment.

Draw a vertical line through the long leg point. That line represents that one particular assessment and the other two data points will be plotted on it.

3. Plot the point for the short leg.Plot the short leg point on the vertical line representing that assessment at the approprate length.

4. Plot the point for the skeletal age.The nomogram area consists of sloping lines representing skeletal ages. Plot the point for the skeletal age where the vertical line for the assesment intersects the appropriate skeletal age, interpolating between the lines if necessary. Be sure to use the nomogram area for the appropriate sex. Points plotted above the 'MEAN' line suggest a child taller than the mean, and points below it a child shorter than the mean. If the skeletal age is not available omit this step.

5. Plot the other assessments.Repeat the above steps for each of the assessments. Each assessment will be represented by a vertical line with three points on it if skeletal age is available, two points if not.

6. Draw the short leg line.Draw the line which best fits the points plotted for the short leg. The fit should be fairly close. If it is not reread the x-rays to check the measurement of any wayward points.

7. Draw the growth percentile line.Draw a horizontal straight line that best fits the points plotted for skeletal age. If the plotted points don't fit well resist the temptation to drawanything other than a horizontal straight line. In that case pay more attention to points of recent assessments than those of older ones.

8. Draw the maturity line.Starting at the intersection of the growth percentile line and the maturity nomogram line, the one furthest right, drop a vertical line the height of the graph. This line represents maturity and the end of growth for the two legs.

9. Extend the growth lines to maturity.Extend the growth lines of the two legs to the right to meet the maturity line. The intersection of these lines with the maturity line predicts the lengths of the legs at maturity in the absence of further surgery.

10. Draw the lines for epiphyseodesis done now.

There are two ways to think about the effects of epiphysiodesis. The first is to predict the effects at maturity of epiphysiosdesis done now.

11. Draw the lines for epiphyseodeses that achieve equality.The second way to think of epiphysiodis is to consider those done at a later time that achieve equal leg lengths at maturity.

12. Draw the line for a lengthening of the short leg.

13. Draw the line for a shortening of the long leg.

fibular hemimelia

Treatment

• Mild to Moderate Fibular Hemimelia• Amputation or Limb Lengthening. • depends on the degree of predicted shortening at

maturity and the condition of the foot and ankle of the affected limb.

• The Birch classification is useful in planning treatment.• If the predicted discrepancy at maturity is 25 cm or

more and there is severe valgus of the ankle with a deformed foot, the patient should be treated with a Syme or Boyd amputation and prosthetic management.

• If the patient has a predicted shortening of 8 cm or less, a functional plantigrade foot with four or more rays, and a stable and mobile ankle, he or she is a good candidate for a lengthening procedure with or without epiphysiodesis.

• The choice of amputation or lengthening for children who fall in between the criteria identified earlier must be made on an individual basis.

• Severe Fibular Hemimelia• Amputation. • Today, the consensus is that ankle

disarticulation is the best treatment for more severe fibular hemimelia.

• modified Syme amputation , the Boyd amputation

• The optimal time to perform the amputation is when the child is just starting to pull up to stand (normally, 9 to 10 months of age).

• Limb Lengthening. • Improved techniques have renewed interest in

limb lengthening procedures to treat deformities and limb length inequality in children with severe fibular hemimelia

• Patients whose discrepancies are less than 5 cm at birth and who do not have significant foot deformities may be suitable candidates;

• For patients whose limb length discrepancies at birth are greater than 5 cm and who are predicted to have more than 30% relative discrepancy, and for those who have notable foot deformities, we concur with Kruger and Birch that the most appropriate treatment consists of amputation and prosthetic management.

1393- 6 Y/O

cm Right left

PF 51.9 52.4

DF 28.6 25.1

FL 23.3 27.3 4

DT 9.1 1.4

TL 19.5 23.7 4.2

LL 42.8 51 LLD:8.2

cm Right left

PF 66.8 64.5

DF 40 33.2

FL 26.8 31.3 4.5

DT 22.6 7.2

TL 17.4 26 8.6

LL 44.2 57.3 LLD:13.1

1394- 8y/o

cm Right left

PF 79.2 74.2

DF 50.3 40.8

FL 28.9 33.4 4.5

DT 32 13.8

TL 18.3 27 8.7

LL 47.2 60.4 LLD:13.2

1395 - 9 y/o

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5cm

Long limb:Both epiphysiodesisShort limb: 5cm lengthening

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20cm

Long limb: 5cm shortening+ distal femoral epiphysiodesisShort leg: 6cm lengthening

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20cm

Long limb: distal femoral epiphysiodesisShort leg: 11cm lengthening