Should a pediatric patient with a 1.1 cm lower limb length discrepancy undergo regular Computed Tomography (CT) Scanogram assessments?

From the Guidelines

Regular CT scanograms are not necessary for monitoring a 1.1 cm lower limb length discrepancy in a pediatric patient. Instead, clinical follow-up with physical examination every 6-12 months is recommended, with imaging performed only when there are significant changes in symptoms or physical findings 1. For a discrepancy of this magnitude (1.1 cm), conservative management is typically appropriate, including shoe lifts or heel inserts to compensate for the difference.

Key Considerations

• CT scanograms expose children to radiation, and the benefits rarely outweigh the risks for routine monitoring of stable, mild discrepancies.
• Alternative imaging methods like standing radiographs or EOS imaging can be considered if imaging is needed, as they deliver lower radiation doses 1.
• The frequency of follow-up should increase during growth spurts, when discrepancies may progress more rapidly.
• If the discrepancy is progressive or causing functional problems like gait abnormalities or back pain, then more frequent assessment and possibly surgical intervention might be warranted.

Management Approach

• Clinical evaluation and monitoring are crucial in managing lower limb length discrepancies in pediatric patients.
• Imaging should be used judiciously, considering the risks of radiation exposure and the potential benefits of monitoring.
• A multidisciplinary approach, including pediatric orthopedic specialists, may be necessary for optimal management of significant limb length discrepancies or associated conditions 1.

From the Research

Management of Lower Limbs Length Discrepancy

• The management of lower limbs length discrepancy in pediatric patients involves various methods, including the use of CT scanograms to evaluate limb length discrepancy 2, 3, 4.
• A study published in 2012 found that a postoperative scanogram in patients with comminuted femoral shaft fractures treated with intramedullary nailing is useful to evaluate LLD and allows for early intervention 2.
• However, another study published in 2005 found that there was no correlation between CT scanogram and clinical measurement of leg length or between CT scanogram and patient perception of limp or LLD, suggesting that physical examination may be more reliable and clinically relevant than CT scanogram measurement in the assessment of LLD after femoral fracture 3.

Repeat CT Scanogram

• There is no clear evidence to suggest that repeating CT scanograms on a regular basis is necessary for managing lower limbs length discrepancy in pediatric patients with a discrepancy of 1.1 cm 2, 3, 4.
• A study published in 2008 recommended the use of a CT scanogram, especially the lateral scout view, in patients with flexion deformities at the knee, but did not provide guidance on the frequency of repeat scans 4.
• Another study published in 2025 found that CT scanogram measurements from the acetabular apex to the tibial plafond often overestimate operative limb length, and recommended using alternative reference landmarks to improve LLD assessment accuracy post-arthroplasty 5.

Alternative Methods

• Alternative methods for assessing leg length discrepancy, such as clinical examination and standing blocks, may be useful screening tools, but are not as accurate as imaging modalities 3, 4.
• A systematic review published in 2018 found that shoe lifts can reduce pain and improve function in patients with LLD and common painful musculoskeletal conditions, but high-quality research is needed to evaluate the effectiveness of this treatment 6.