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 (Fig. 82-1).
Salter-Harris classification of physeal injuries. The portion of the bone proximal to the thick black line is the metaphysis; the thick green line represents the physis (growth plate), and the portion distal to the physis is the epiphysis.
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. Bone growth is undisturbed. Diagnosis is suspected clinically in children with point tenderness over a growth plate. 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.
Salter-Harris Type II Fracture
Type II physeal fracture is the most common (75%) physeal fracture. The fracture goes through the physis and out through the metaphysis. Growth is preserved because the physis remains with the epiphysis. Treatment is closed reduction (if necessary) with analgesia and sedation followed by cast immobilization.
Salter-Harris Type III Fracture
The hallmark of type III physeal fracture is an intraarticular 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. Reduction of the unstable fragment with anatomic alignment of the articular surface is critical. Open reduction is sometimes required.
Salter-Harris Type IV Fracture
The fracture line of type IV physeal fractures begins at the articular surface and extends through the epiphysis, physis, and metaphysis. Especially when there is displacement of the bony fragments, open reduction is required to reduce the risk of premature bone growth arrest.
Salter-Harris Type V Fracture
In type V physeal fracture, the physis is essentially crushed by severe compressive forces. There is no epiphyseal displacement. The diagnosis is often difficult. An initial diagnosis of sprain or type I injury may prove incorrect when later growth arrest occurs. Radiographs may look normal or demonstrate focal narrowing of the epiphyseal plate. There is usually an associated joint effusion. Treatment consists of cast immobilization, nonweight bearing, and close orthopedic follow-up in anticipation of ...