Salter-Harris classification

The Salter-Harris classification, published in 1963, describes how a fracture runs through the growth plate (physis) in a child. The type tells you whether the joint surface needs anatomic repair and how worried to be about growth. The mnemonic is SALTR.

Type I, Straight across: through the physis only. The X-ray can look normal.

Type II, Above: through the physis and out through the metaphysis. The commonest type, at 54% of physeal fractures in one population study.

Type III, Lower: through the physis and the epiphysis, into the joint.

Type IV, Through: through the metaphysis, physis and epiphysis, also into the joint.

Type V, Rammed: a crush injury of the physis, often recognised only later, when growth stops.

Displaced types I and II are usually reduced closed and put in a cast, though some unstable patterns need fixation. Types III and IV enter the joint, so they need anatomic reduction, often with fixation, to restore the surface and avoid a bony bridge across the physis. Type V leaves little to reduce, and the concern is growth arrest. In every type, explain the risk of growth disturbance to the family and arrange follow-up.

Type V is the one you miss, because the first film is usually normal. The opposite trap is the child with lateral ankle tenderness over the distal fibular growth plate and a normal X-ray, who is often labelled Salter-Harris I. In an MRI study of 135 such children aged 5 to 12, only 4 (3.0%) had that fracture, and 80% had ligament injuries. Treated in a removable brace, children with and without a fibular fracture recovered about equally at 1 month.

Viva question: A 10-year-old has lateral ankle tenderness and a normal X-ray. How do you manage the child, and why?

Read more: Salter and Harris, J Bone Joint Surg Am, 1963 · Peterson et al., J Pediatr Orthop, 1994 · Boutis et al., JAMA Pediatr, 2016

Education only, not medical advice. Management depends on the patient and your local protocol.