The Salter-Harris fracture is a common injury in children, involving the growth plates of the long bones. Approximately 15% to 30% of all childhood fractures are growth plate fractures and are common in the lower leg bones (tibia and fibula). It is important to detect these fractures as they may affect the growth of the bone if not treated properly.
There are five types of Salter-Harris fractures. The higher the type number, the more complications associated with the fracture.
Only 5% of fractures are Type I. It may be difficult to diagnose unless there is obvious displacement and sometimes the diagnosis is a clinical one. Type I fractures occur though the weak zone of the provisional calcification and are known for their fast healing and rare complication rate.
Approximately 75% of fractures are type II. These fractures occur at the physis (growth plate) and metaphysis – and when the corner of the metaphysis separates (Thurston-Holland Sign). The fragment usually stays with the epiphysis while the rest of the metaphysis will displace. Typically, healing is fast and growth is usually okay; however, distal femur fractures may result in growth deformity.
10% of fractures are Type III, which are defined as fractures of the growth plate and epiphysis, or even a split of the epiphysis. The fractures extend into the articular surface of the bone and will require reduction of the joint. In distal femur fractures it may result in a growth deformity.
About 10% of fractures are Type IV fractures—which pass through the epiphysis, physis (growth plate), and the metaphysis. Type IV fractures can cause complications such as growth disturbance and angular deformity.
Type V fractures are uncommon, only occurring about 5% of the time. In type V fractures, compression or a crush injury of the growth plate takes place. This fracture has no association with the epiphysis or metaphysis and an initial diagnosis may be difficult. Despite being uncommon, these fractures have the highest incidence of growth deformity and disturbance.