eMedicine Specialties > Radiology > Pediatrics

Salter-Harris Fractures

Author: William Moore, MD, Staff Physician, Department of Radiology, State University of New York at Stony Brook University Medical Center
Coauthor(s): Thomas H Smith, MD, Associate Professor, Departments of Radiology and Pediatrics, State University of New York at Stony Brook
Contributor Information and Disclosures

Updated: Jul 27, 2009

Introduction

Background

Salter-Harris fractures are fractures through a growth plate; therefore, they are unique to pediatric patients. Several types of fractures have been categorized by the involvement of the physis, metaphysis, and epiphysis. The classification of the injury is important because it affects the treatment of the patient and provides clues to possible long-term complications.

Pathophysiology

The histologic features of the physis are important for understanding the prognosis of physeal fractures. The germinal layer of the cartilage is on the epiphysis and derives nutrition from the epiphyseal vessels. Cartilage cells grow from the epiphysis toward the metaphysis, forming columns of cells that degenerate, fragment, and undergo hypertrophy. The fragments of cells mineralize. This is the zone of provisional calcification forming the metaphyseal border and is not bone. Note that no circulation exists in the cartilage zone.

Neovascularization occurs from the metaphysis toward the epiphysis. Endothelial cells transform into osteoblasts and use the degenerate cell debris to form primary immature bone. This immature bone progressively is remodeled to mature woven bone and, further, is remodeled by cutting cones to form mature haversian system bone. Damage to either epiphyseal or metaphyseal vascular supply disrupts bone growth; however, damage to the layer of cartilage may not be significant if the surfaces are reapposed, and vascular supply to the growing cartilage is not permanently interrupted. When the 2 vascular beds touch, the physis is closed (fused) and no further bone growth is possible.

Age

Salter-Harris fractures are injuries through the physis. Therefore, by definition, they must occur before the physis closes. Typically, physis closure occurs during the teenage years.

A study by Mubarak et al showed that proximal tibial fractures are age-dependent in relation to mechanism, location, and Salter-Harris type. Metaphyseal fractures predominated in the youngest population (ages 3-6 years), with tibial spine fractures occurring at age 10, Salter-Harris type I and II fractures at age 12, and Salter-Harris type III and IV physeal injuries around age 14 years.¹

Presentation

The classification of Salter-Harris fractures is used to describe the extent and site of the epiphyseal injuries. The basic types of  Salter-Harris fracture include the following^{1,2,3,4,5,6,7} :

• Type I
  • A type 1 fracture is a transverse fracture through the hypertrophic zone of the physis. In this injury, the width of the physis is increased. The growing zone of the physis usually is not injured, and growth disturbance is uncommon.
  • On clinical examination, the child has point tenderness at the epiphyseal plate, which is suggestive of a type I fracture.
• Type II
  • A type II fracture is a fracture through the physis and the metaphysis, but the epiphysis is not involved in the injury.
  • These fractures may cause minimal shortening; however, the injuries rarely result in functional limitations.
  • Type II is the most common type of Salter-Harris fracture.
• Type III
  • A type III fracture is a fracture through the physis and the epiphysis. This fracture passes through the hypertrophic layer of the physis and extends to split the epiphysis, inevitably damaging the reproductive layer of the physis.
  • This type of fracture is prone to chronic disability because by crossing the physis, the fracture extends into the articular surface of the bone.
  • However, type III fractures rarely result in significant deformity; therefore, they have a relatively favorable prognosis.
  • A type of ankle fracture termed a Tillaux fracture is a type of Salter-Harris type III fracture that is prone to disability.
  • The treatment for this fracture is often surgical.
• Type IV
  • A Type IV fracture involves all 3 elements of the bone: The fracture passes through the epiphysis, physis, and metaphysis.
  • Similar to a type III fracture, a type IV fracture is an intra-articular fracture; thus, it can result in chronic disability.
  • By interfering with the growing layer of cartilage cells, these fractures can cause premature focal fusion of the involved bone. Therefore, these injuries can cause deformity of the joint.
• Type V
  • A type V injury is a compression or crush injury of the epiphyseal plate with no associated epiphyseal or metaphyseal fracture.
  • This fracture is associated with growth disturbances at the physis. Initially, diagnosis may be difficult, and it often is made retrospectively after premature closure of the physis is observed. In the older teenagers, the diagnosis is particularly difficult.
  • The clinical history is paramount in the diagnosis of this fracture. A typical history is that of an axial load injury.
  • These injuries have a poor functional prognosis.

When all types of Salter-Harris fractures are considered, the rate of growth disturbance is approximately 30%. However, only 2% of Salter-Harris fractures result in a significant functional disturbance.

Rare types of Salter-Harris fractures include the following:

• Type VI: This is a rare injury and consists of an injury to the perichondral structures.
• Type VII: This is an isolated injury to the epiphyseal plate.
• Type VIII: This is an isolated injury to the metaphysis, with a potential injury related to endochondral ossification.
• Type IX: This is an injury to the periosteum that may interfere with membranous growth.

Preferred Examination

Radiography always is the preferred examination in a suspected fracture. The use of another modality should not be considered until appropriate plain film radiography has been performed.^{8,9,10,11,12,13,14}

In cases of severe injury in which the patient has acute pain, appropriate radiographic examination of the involved area may be difficult because of inadequate patient positioning. In these cases, CT may be beneficial in evaluating the injury after a radiologist has evaluated the plain radiographs. However, the cost of CT may prohibit its use in all cases in which the area of interest is suboptimally evaluated. CT should be considered only when radiographic findings are insufficient. Typically, an orthopedic surgeon and a radiologist make the decision to perform CT.

If an additional study is performed, its purpose is to determine the appropriate management and to assist in surgical planning. Thus, the surgeon performing the operation is best suited to request the imaging study. When further definition of fractures may help in making management decisions or when the injury does not respond to conservative management, the radiologist or orthopedic surgeon can recommend an appropriate examination to perform after plain radiography.

Currently, 2 radiologic examinations can be performed to further evaluate fractures: (1) CT with multiplanar reconstruction and (2) MRI. MRI depicts marrow edema, whereas CT shows cross-sectional bone detail and tomographic multiplanar information. The use of MRI in the evaluation of fractures is described below, but it is still in its infancy. At the present time, MRI is not the standard of care. CT is used more commonly; typically, it is used for planning surgery.

Limitations of Techniques

The primary disadvantages of MRI are related to its expense, time requirement, and availability, which limit the routine use of MRI. As techniques and software improve, the use of MRI in the acute trauma setting is likely to increase.

Differential Diagnoses

[Elbow Trauma - Pediatric]
Ankle, Fractures
Wrist, Scaphoid Fractures and Complications

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