Limb Length Discrepancy and Osteogenesis Imperfecta: Preventable or Inevitable?
Bethany Graulich1, Katie Liu2, Jill C Flanagan3
1Washington University, St Louis, MO.
Journal of Pediatric Orthopedics
|August 4, 2025
Summary
Limb length discrepancy (LLD) affects over 90% of children with osteogenesis imperfecta (OI), regardless of severity or surgical intervention. LLD in OI does not follow predictable growth patterns.
Area of Science:
- Pediatric Orthopedics
- Genetics and Musculoskeletal Disorders
Background:
- Osteogenesis imperfecta (OI) is a genetic disorder affecting collagen, leading to brittle bones and deformities.
- Surgical intervention, primarily intramedullary rodding, is used for progressive deformities in OI.
- Limb length discrepancy (LLD) is a known complication, but its prevalence and contributing factors in OI are not well understood.
Purpose of the Study:
- To determine the prevalence of LLD in children with osteogenesis imperfecta (OI).
- To identify risk factors associated with LLD in pediatric OI patients.
- To analyze the longitudinal changes in LLD over time in OI patients.
Main Methods:
- A retrospective study of 78 children with OI, including 30 nonoperative and 48 operative cases.
- Longitudinal tracking of LLD using full-length lower extremity radiographs over a minimum of two years.
- LLD defined as a >5 mm difference in combined femur and tibia length; surgical patients required 18 months of postoperative data.
Main Results:
- LLD was observed in 90% of nonoperative and 96% of operative patients.
- Mean LLD was significantly higher in the surgical group (1 cm) compared to the nonoperative group (0.43 cm).
- No association found between LLD and OI severity, ambulation status, or number of rods; LLD progression varied individually.
Conclusions:
- The prevalence of LLD in children with OI exceeds 90% across all severities.
- Surgical intramedullary rodding is not an independent risk factor for developing LLD in OI.
- LLD in OI patients does not exhibit a consistent growth pattern, with individual variations observed over time.
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