Limb Length Discrepancy

LLD can be classified based on whether the difference is due to bone length or functional problems.

• Structural LLD is a condition in which there is a true difference in bone length caused by congenital or acquired conditions.
• Functional LLD is a condition in which the bones are equal in length, but differences arise due to joint contractures, muscle weakness, or pelvic tilt.
   

Patients with LLD may notice changes in walking and posture, which can lead to pain or balance problems.

• Uneven walking pattern
• Limping
• Difficulty in balance and coordination
• Backpain

LLD can result from conditions present at birth or acquired later in life due to injury or illness.

• Congenital (since birth) conditions like:
  • Femoral deficiency (loss of the thigh bone)
  • Hip dislocation and genetic conditions like Down’s syndrome or Turner’s syndrome
• Acquired conditions like:
  • Injuries to the limb growth plate
  • Bone infection
  • Post-traumatic malunion and tumours
  • Muscle weakness or contractures and joint contractures

Doctors use clinical assessment and imaging tests to measure limb length and identify the underlying cause.

• Measurement of true limb length, pelvic tilt, and shoulder drop.
• Observation of the walking pattern.
• X-ray of both lower limbs that should include pelvis and ankle joint.
• Computed tomography (CT) to assess bone involvement or childhood bone disorder
• Magnetic resonance imaging (MRI) to assess the soft tissues around the bones and joint.
   

Based on the severity of the condition and the patient’s age, one or more of the following treatment approaches may be recommended:

• Non-surgical treatment:
  • Observation in patients with a discrepancy of less than 2 cm.
  • Orthotic devices like heel raises, shoe lifts, and extension prostheses.
• Surgical treatment:
  • Epiphysiodesis involves putting plates or screws to restrict the growth either on one or both sides of a particular bone.
  • Osteotomy involves lengthening or shortening the bone surgically based on the indication and requirement.

Medical attention is recommended if a visible difference in leg length affects walking, balance, or causes pain.

While congenital LLD cannot be prevented, early detection and treatment of injuries, infections, or bone disorders can help prevent acquired LLD.

An orthopaedic surgeon (preferably a paediatric orthopaedic surgeon for children) is the right specialist to consult for diagnosis and treatment.