Physeal Injuries — Salter–Harris & Ogden

Physeal (growth plate) injuries are unique to the skeletally immature patient and account for approximately 15–30% of all fractures in children. The physis is the weakest link in the paediatric musculoskeletal system — weaker than the surrounding periosteum, ligaments, and joint capsule. This has profound implications for fracture patterns and the risk of growth disturbance.

• The physis consists of four zones: reserve (germinal), proliferative, hypertrophic, and calcification zones
• Fracture typically occurs through the zone of provisional calcification (hypertrophic zone) — weakest zone, least cellular, most susceptible to shear
• Most common sites: distal radius (most common overall), distal tibia, distal fibula, proximal humerus, proximal tibia
• Peak incidence: boys aged 12–15 years; girls aged 10–13 years (correlating with pubertal growth spurt)
• Risk of growth disturbance depends on: injury type, energy, age of patient, specific physis, and adequacy of reduction
• The distal femoral physis contributes the most to overall limb length — approximately 70% of femoral growth and 37% of total lower limb length

The Salter-Harris (SH) classification (1963) is the universally used system for physeal injuries. It is based on the relationship of the fracture line to the physis, epiphysis, and metaphysis.

• Mnemonic: SALTR — Same (I), Above (II), Lower (III), Through (IV), Ram/Crush (V)
• Type II most common; Type V rarest and worst prognosis
• Types III and IV are intra-articular — anatomic reduction is mandatory to restore joint congruity and physeal alignment
• Types I and II — periosteum usually intact on one side (hinge) — aids closed reduction

The Ogden classification (1981) extends Salter-Harris by adding Types VI–IX to capture injury patterns not described in the original system.

• Ogden Types VI–IX are less commonly examined but important for understanding growth disturbance in atypical injuries
• Type VI (perichondrial ring injury) — peripheral physeal bar forms; causes angular deformity rather than length discrepancy
• Type VII — purely epiphyseal; no direct physeal disruption but osteochondral fragment may block joint

• Epiphyseal blood supply enters via the epiphysis — vulnerable in injuries where epiphysis is displaced or devascularised
• Distal femoral epiphysis: entirely intraepiphyseal blood supply — SH I or II injuries can disrupt supply; high AVN risk with significant displacement
• Proximal femoral epiphysis: blood supply via retinacular vessels — extremely vulnerable; SH I/II injuries cause AVN in up to 40% (slipped capital femoral epiphysis is a chronic SH I equivalent)
• Physeal bar formation (growth arrest): bony bridge forms across physis — leads to LLD or angular deformity depending on location
• Central bar — causes length discrepancy (tenting, cupping)
• Peripheral bar — causes angular deformity; correctable with bar resection if <50% of physeal area involved and >2 years growth remaining
• Physeal bar resection (Langenskiöld): interpose fat graft; indicated for <50% bar, >2 years growth remaining; good results in selected cases
• Park-Harris growth arrest lines: transverse lines in metaphysis visible on radiograph after injury — used to predict remaining growth and LLD

• SH I and II: closed reduction and cast immobilisation; acceptable alignment in most cases; avoid forceful repeated reductions — can cause physeal damage
• SH III and IV: anatomic reduction mandatory — articular and physeal congruity must be restored; ORIF with smooth K-wires or cannulated screws placed parallel to or through physis (epiphysis to epiphysis) if possible — avoid crossing physis with large threaded screws
• Screws crossing the physis: smooth wires preferred; threaded screws crossing growth plate should be removed early to avoid iatrogenic tethering
• Repeat manipulation should be avoided after 7–10 days — risk of physeal damage from callus disruption outweighs benefit of improved alignment
• Follow-up: all physeal injuries should be reviewed clinically and radiographically at 3 months, 6 months, and 1 year minimum — monitor for growth arrest lines and angular deformity
• Non-accidental injury (NAI): physeal fractures, particularly SH I and metaphyseal corner fractures in infants, should raise suspicion — full skeletal survey if NAI suspected

• Tillaux and triplane fractures: both occur at predictable window of physeal closure (12–15 years) — understanding the closure sequence (central first, then medial, then lateral) explains the fracture pattern; CT is mandatory for operative planning in both
• Distal femoral physeal injuries — never underestimate growth arrest risk; even SH II injuries can cause significant LLD due to the high growth contribution of this physis; inform parents and arrange long-term follow-up
• MRI for occult physeal injuries: in children with clinical suspicion of physeal injury but normal radiographs (e.g. point tenderness over physis, pain limiting weight bearing) — MRI detects physeal oedema and confirms injury; avoids unnecessary repeated X-rays
• Predicted LLD calculation: use Green-Anderson growth charts or Moseley straight-line graph — assess skeletal age (bone age from non-dominant hand X-ray), measure LLD, plan timing of epiphysiodesis to achieve limb length equalisation at skeletal maturity
• Epiphysiodesis timing: percutaneous epiphysiodesis (Canale technique / screw epiphysiodesis) of contralateral longer limb — must be timed precisely; premature leads to undercorrection; late leads to overcorrection
• Physeal bar resection: Langenskiöld procedure with fat graft interposition — indicated for peripheral bar <50% cross-sectional area with >2 years growth remaining; CT or MRI to map bar location; excellent results if criteria met

• SH II = most common (75%); SH V = rarest, worst prognosis (crush injury)
• Fracture occurs through zone of provisional calcification — weakest zone of physis
• SH I and II — low growth arrest risk; SH III and IV — moderate; SH V — near 100%
• SH III and IV = intra-articular — anatomic reduction mandatory; ORIF if displaced >2 mm
• Distal femoral physis = 70% of femoral growth = 37% total lower limb length — monitor all injuries long-term
• Proximal tibia SH injury — urgent vascular assessment; popliteal artery tethered and at risk
• Tillaux = SH III distal tibia lateral epiphysis; triplane = SH IV equivalent; both during physeal closure 12–15 years — CT mandatory
• Lateral condyle humerus = SH IV equivalent — missed = cubitus valgus and tardy ulnar nerve palsy
• Peripheral physeal bar = angular deformity; central bar = LLD — peripheral bar resection if <50% area, >2 years growth remaining
• Screws across physis — smooth wires preferred; threaded screws must be removed early
• Repeated manipulation after 7–10 days risks physeal damage — accept reasonable alignment rather than re-manipulate late