Salter Harris Classification : The Must Know Topic in Orthopedics

Salter-Harris Classification — Notes

Used to classify pediatric fractures involving the growth plate (physis), since growth plate injuries carry risk of growth disturbance and need different management than adult fractures.

Mnemonic: SALTR

Type	Name	Description
I	Slip	Fracture through the physis only (growth plate slips/separates from metaphysis and epiphysis). Epiphysis separates cleanly.
II	Above	Fracture through physis and metaphysis (spares epiphysis). Most common type (~75%).
III	Low (below)	Fracture through physis and epiphysis (spares metaphysis). Extends into the joint.
IV	Through	Fracture through metaphysis, physis, and epiphysis — crosses all three.
V	Rammed (crush)	Compression/crush injury to the physis, with no obvious fracture line. Often missed on initial imaging.

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Key details per type

Type I

• Physis alone; epiphysis separates from metaphysis
• Can be subtle on X-ray — may only show soft tissue swelling if non-displaced
• Good prognosis generally

Type II

• Most common (~75% of all Salter-Harris fractures)
• Fracture line runs through physis then exits through metaphysis, creating a metaphyseal fragment (“Thurston-Holland fragment”)
• Generally good prognosis

Type III

• Intra-articular fracture (involves the joint)
• Risk of growth disturbance is higher since it crosses the epiphysis
• Often needs anatomic reduction (sometimes surgical) due to joint involvement

Type IV

• Crosses metaphysis, physis, and epiphysis
• High risk of growth arrest/deformity if not perfectly reduced
• Usually requires surgical fixation (ORIF) for precise alignment

Type V

• Rare
• Crush injury to the growth plate without a clear fracture line
• Often diagnosed retrospectively after growth arrest is noted
• Worst prognosis for growth disturbance despite normal-looking initial X-ray

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General prognosis pattern

Higher the number, the higher the risk of growth disturbance — I and II generally heal well; III and IV carry more risk (especially IV); V has the worst prognosis despite looking mild initially.

Clinical relevance

• Growth plate injuries only occur in skeletally immature patients (open physes)
• Any suspected physeal injury in a child with point tenderness over a growth plate should be treated as a fracture even if X-ray looks normal (especially Type I and V, which can be radiographically silent)
• Follow-up imaging (weeks to months later) is often used to check for growth arrest lines (Harris lines) or limb-length discrepancy