Anatomy
Distal femur physis
- fuses 14 in girls / 16 in boys
- 70% of growth of femur
- 405 of growth of lower limb
- 1 cm per year
Physis has three main undulatations
Epidemiology
Average age 10 - 11 years
Falls / MVA
NAI - distal femur fractures prior to walking
Associated injuries
Incidence of ACL injuries
Types
Distal femur fractures not involving physis
Growth plate fractures - Salter Harris Type II most common 60%
Salter Harris Type I
Salter Harris Type II
Salter Harris Type III
Supracondylar distal femur fracture
Management
Undisplaced
Extension plaster 6 weeks
Supracondylar without physeal involvement
Options
Plate
Antegrade flexible nails
Salter Harris Type I / Type II with minimal metaphyseal bone
Option
Reduce
Cross K wires - can be unstable and lose position
Technique
Salter Harris Type II
Technique
Large Thurston-Holland fragment
- physeal sparing metaphyseal screws
Block to reduction
- often medial sided periosteum
- may need small medial subvastus / anteromedial approach
Complications
Complete growth arrest
Monitor 6 monthly
- plot short and long leg lengths on Mosely chart
- distal femur contributes 9 mm / year
Manage LLD as per predicted difference
- usually contralateral femoral epiphysiodesis if < 5 mm
- may need femoral lengthening / ISKD on maturity if > 5 mm
Partial growth arrest / angular deformity
Management
CT / MRI - assess percentage of bony bridge
Bony bridge < 50%
- excision and fat graft
- manage angular deformity with 8 plates / osteotomy
Bony bridge > 50%
- hemi-epiphysiodesis
- may need correction of LLD and angular deformity
- opening wedge femoral osteotomy
