Courtesy: Prof Nabil Ebraheim, University of Toledo, Ohio, USA
Neonatal distal femoral physeal injury
Definition
- A rare birth injury involving:
- Separation of the distal femoral physis
- Equivalent to:
- Salter-Harris classification Type I injury
Epidemiology
- Rare in neonates
Comparison with Other Physeal Injuries
- More common sites:
- Distal humerus
- Less common:
- Distal femur
Etiology
Primary Cause: Birth Trauma
- Difficult delivery
- Breech presentation
Result
- Physeal separation
- Displacement of epiphysis
Pathoanatomy
- Distal femur in neonates is:
- Predominantly cartilaginous
Ossification Center
- May be:
- Small
- Absent (especially in premature infants)
Clinical Features
- Swollen thigh
- Pain / irritability (fussy neonate)
- Pseudoparalysis
- Abnormal limb mobility
Diagnosis
X-ray Findings
- Often difficult to interpret
Reason
- Epiphysis may not be ossified
Key Clue
- Ossification center:
- Not aligned with femoral shaft
MRI (Best Investigation)
- Confirms diagnosis when X-ray is inconclusive
- Clearly demonstrates:
- Physeal separation
- Cartilage injury
Differential Diagnosis
1. Congenital knee dislocation
Features
- Abnormal tibia–femur alignment
- Spectrum:
- Hyperextension
- Subluxation
- Dislocation
Key Difference
| Condition | Pathology |
|---|---|
| Physeal injury | Epiphysis separated from femur |
| Congenital knee dislocation | Tibia–femur misalignment |
Management
Primary Treatment
- Gentle closed reduction
- Immobilization
Follow-Up
- Essential to:
- Confirm reduction
- Detect complications early
Complications
- Growth disturbance
- Physeal arrest
- Limb length discrepancy
High-Yield Exam Points
- Rare neonatal injury – think birth trauma
- X-ray may be misleading – MRI is key
- Always differentiate from:
- Congenital knee dislocation
- Treatment:
- Gentle reduction + close follow-up
Clinical Insight
- Because the distal femoral epiphysis is largely cartilage, injuries can be:
- Easily missed on X-ray
- But clinically significant
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