Paediatric Femur Fractures by Age

Paediatric femoral shaft fracture treatment is a classic age-based topic, but age is only the start. The final plan depends on age, weight, skeletal maturity, fracture pattern, length stability, soft tissues, associated injuries, mechanism, safeguarding concerns and the family’s ability to manage immobilisation and follow-up.

Younger children heal quickly and remodel well, but they also need careful assessment of whether the mechanism fits developmental ability. School-age children sit in the transition zone where spica casting may be burdensome and operative stabilisation is often attractive. Adolescents behave more like adults mechanically, but many still have open physes, so implant entry point and growth safety remain important.

The major pattern distinction is length-stable versus length-unstable. A transverse or short oblique fracture may be well suited to flexible intramedullary nails in an appropriately sized child. A long oblique, spiral, comminuted or segmental fracture is more likely to shorten and may need submuscular plating, external fixation or another stability strategy.

Outcome is not just radiographic union. A good result includes acceptable length, rotation, angulation, hip and knee motion, skin integrity, family functioning, safe return to activity and no missed safeguarding or polytrauma issue.

The biology explains why children can often be treated differently from adults, but it also explains the complications.

History

The history should place the fracture in the context of the whole child.

Examination

Perform a paediatric trauma assessment before discussing implant choice.

• Always include hip and knee on femur imaging.
• Look for distal femoral physeal injury and femoral neck injury in high-energy trauma.
• A spiral femur fracture is not automatically abuse, but the mechanism must fit.
• Post-treatment X-rays should confirm length, angulation and implant position.
• Follow-up imaging checks union and maintenance of alignment.

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Treatment is a ladder, not a single rule. Start with analgesia, splintage, skin and neurovascular care, and whole-child assessment. Then choose definitive treatment based on age, size, pattern and context.

Acceptable deformity by age (what "acceptable alignment" actually means)

Remodelling potential falls with age, so the tolerated deformity narrows as the child gets older. Younger children also overgrow, so bayonet shortening of up to ~1.5–2 cm is deliberately accepted in the under-10s. Rotation remodels poorly at every age and is not "accepted" — it must be corrected.

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Early

• Compartment syndrome.
• Skin breakdown or cast problems.
• Loss of reduction or shortening.
• Open fracture infection.
• Associated injuries missed in polytrauma.

Late

• Malrotation.
• Limb length discrepancy from overgrowth or shortening.
• Knee stiffness after flexible nailing or immobilisation.
• Refracture after early implant removal.
• AVN risk with inappropriate rigid nail entry.

Age-based paediatric femoral shaft fracture treatment is a shortcut for a larger decision: age, weight, fracture stability, soft tissues, mechanism, family care capacity and associated injuries. The wrong operation for the wrong age or fracture pattern creates malunion, malrotation, skin problems or avoidable reoperation.

Common pitfalls

• Choosing treatment from age alone.
• Missing non-accidental injury.
• Ignoring femoral neck or knee associated injury.
• Using flexible nails for an unstable comminuted fracture without plan for shortening.
• Not checking rotation.
• Discharging a spica family without practical education.

Paediatric femoral shaft fractures are common worldwide, but implants, resources and pathways differ. The principles below let you defend a plan in any examination system.

Global epidemiology

• Femoral shaft fractures account for roughly 1.5 to 2% of all paediatric fractures, with a bimodal age distribution: a peak in toddlers (often low-energy or non-accidental) and a second peak in adolescents (high-energy).
• There is a consistent male predominance and a strong association of the youngest fractures with non-accidental injury (see Clarke et al, Injury 2012).
• In a non-ambulant infant, abuse rather than implant choice is the dominant clinical question.

Side-by-side guidance

Registry and outcome notes

• Paediatric femoral shaft fractures are not tracked in arthroplasty registries (NJR, AJRR, AOANJRR), so evidence comes from institutional series and meta-analyses rather than implant-survival registries.
• The most robust comparative evidence is from systematic reviews of flexible nailing versus submuscular plating (Hu et al 2023; Liu et al 2024), which show comparable union and complication trade-offs rather than a single superior implant.

High-resource versus limited-resource practice

The age-based framework hides several genuinely contested decisions. These are the points examiners use to separate a safe trainee from a thinking one.