Leg Length Discrepancy

Leg length discrepancy may be structural or functional. Predicting the final difference with growth charts or the multiplier method guides treatment, from a shoe raise for small differences to epiphysiodesis of the longer leg or limb lengthening for larger ones.

Leg Length Discrepancy, pelvic radiograph showing leg length discrepancy after hip arthroplasty
Pelvic radiograph showing leg length discrepancy after hip arthroplasty. Image by Mikael Häggström, from source image by Nevit Dilmen, Wikimedia Commons, CC0.

Growth

Menelaus Rule

  • 54% of length from femur
    • proximal 4 mm/year
    • distal- 9mm/yr
  • 46% from tibia
    • proximal 6mm/yr
    • distal – 4mm/yr

Green & Anderson Chart

  • plots growth remaining

Straight Line Graph of Moseley

  • a manipulation of the Green Anderson Data

Data Analysis

Arithmetic Method – Menelaus

  • Assume physis grow at 4,9,6,4 mm / year
  • Assume that
    • girls stop growing at 14
    • boys at 16 years
  • Inhibition is calculated
  • Growth of the long leg
    • growth of the short leg/ growth of the long leg
  • Essentially gives the amount that the short leg is losing for each cm of growth by the healthy leg
  • Future Discrepancy = current discrepancy + (Growth remaining in the leg) (inhibition)

Growth Remaining Method of Green & Andersen

  • Uses Green Anderson charts of growth remaining in distal femur and proximal tibia by skeletal age
  • Skeletal age from a hand and wrist X-ray using the Greulich and Pyle atlas
  • Percentage growth inhibition calculated from at least two serial measurements
  • Predicted discrepancy equals current discrepancy plus normal limb growth remaining multiplied by inhibition
  • Charts give the timing of epiphysiodesis for the correction required
  • Assumes a constant percentage inhibition through growth

Straight Line Method (Moseley)

  • Plot the long(normal) leg on the reference slope
  • Plot the short leg below this
  • Now plot the skeletal age based on calendar or wrist X-ray
  • Draw in more points
  • Get an average age curve & draw this out to where it ends for girl or boy respectively
  • Drop a perpendicular which  will hit the long leg at maturity
  • Line of best fit for short leg intersects this perpendicular to give length at maturity
  • epiphysiodesis lines  show what happens if you change the slope o
  • These methods assume a stable inhibition

Inadequate Data

  • Extrapolate back to the time when both legs were O length

Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.