CHILDHOOD PATTERNS OF INJURY
The growth plate (physis) is the weakest point in children’s long bones and the frequent site of fractures. The ligaments and periosteum are stronger than the physis; therefore, they tolerate mechanical forces at the expense of physeal injury. The blood supply to the physis arises from the epiphysis, so separation of the physis from the epiphysis may result in growth arrest. The Salter–Harris classification is used to describe fractures involving the growth plate (Figs. 82-1 and 82-2).
Salter–Harris type II fracture of distal tibia. Lateral radiograph illustrating fracture extending through physeal growth plate and metaphysis with dorsal displacement of epiphysis requiring reduction. Used with permission from Wake Medical Center, Raleigh, NC.
An x-ray of a Salter–Harris type III fracture of the distal tibia, also known as Tillaux’s fracture. Note the intra-articular component extending through the growth plate and the medial epiphysis of the tibia. Reproduced with permission from Schafermeyer RW, Tenebein M, Macias CG: Strange and Schafermeyer's Pediatric Emergency Medicine, 4th ed. New York: McGraw-Hill, Inc; 2015.
Salter–Harris Type I Fracture
In type I physeal fracture, the epiphysis separates from the metaphysis. The reproductive cells of the physis stay with the epiphysis. There are no bony fragments, and these injuries have a low incidence of growth disturbance. Diagnosis is suspected clinically in children with point tenderness over a physis. On radiograph, there may be no abnormality; there may be an associated joint effusion; or there may be epiphyseal displacement from the metaphysis. In the absence of epiphyseal displacement, the diagnosis is clinical. Treatment consists of splint immobilization, ice, elevation, and referral to orthopedics. Type I fractures of the distal fibula are not associated with growth arrest and can be followed by a primary care physician (PCP) or by orthopedics after splinting.
Salter–Harris Type II Fracture
A type II physeal fracture goes through the physis and out through the metaphysis. Growth is preserved because the physis remains with the epiphysis. Diagnosis is made by noting a metaphyseal triangular-shaped fragment without epiphyseal involvement on radiograph. Treatment is closed reduction (if necessary) with analgesia and sedation followed by splint or cast immobilization, and follow-up with orthopedics.
Salter–Harris Type III Fracture
The hallmark of type III physeal fracture is an intra-articular fracture of the epiphysis with the cleavage plane continuing along the physis. The prognosis for bone growth depends on the circulation to the epiphyseal bone fragment and is usually favorable. Diagnosis is made radiographically with an epiphyseal fragment without a metaphyseal fracture. Reduction of the unstable fragment with anatomic alignment of the articular surface is critical. Open reduction is sometimes required.