Review Question - QID 217126

This patient who presents with a fall onto an outstretched hand with elbow pain, swelling, refusal to pronate or supinate the forearm, and a cortical discontinuity stretching from the proximal radial physis to the metaphyseal portion of the radius has a Salter-Harris type 2 radial head and neck fracture.

The Salter-Harris classification is the most common method of classifying pediatric fractures that involve the physis of a developing long bone. The classification is based on the extension of the fracture line to the epiphyseal or metaphyseal side of the physis. A Salter-Harris type 1 fracture is a fracture that traverses the physis but does not extend to either side of the physis. A Salter-Harris type 2 fracture also involves the metaphysis resulting in a triangular fragment known as a Thurston Holland fragment. A Salter-Harris type 3 fracture also involves the epiphysis and is at higher risk of growth arrest. A Salter-Harris type 4 fracture involves both the metaphysis and the epiphysis and can result in shearing of the entire fragment from the rest of the bone. Finally, a Salter-Harris type 5 fracture is complete destruction of the physis and is at a very high risk of growth arrest. Treatment of pediatric radial head/neck fractures typically consists of either casting or percutaneous pinning depending on fracture displacement and angulation.

Dragoni et al. studied intraarticular radial head fractures in pediatric patients. They found that these fractures are often underdiagnosed. They recommended that physicians should be vigilant in assessing for radial head fractures in pediatric patients to avoid growth arrest from an untreated fracture.

Figure/Illustration A is an anteroposterior radiograph of the elbow in a skeletally immature patient. The radial head (red circle) has a cortical discontinuity that extends from the physis through the lateral aspect of the metaphysis consistent with a Salter-Harris type 2 fracture.

Incorrect Answers:
Answer 1: Lateral condyle fractures are a type of pediatric elbow fracture that occur on the lateral aspect of the humerus. This injury would present with a cortical discontinuity on the articular aspect of the distal humerus. The line that is visualized in the radiograph in this area represents a developing physis rather than a fracture in this patient. Treatment consists of casting or percutaneous pinning depending on displacement.

Answer 2: Medial epicondyle fractures are a type of pediatric elbow fracture that occur on the medial aspect of the humerus. This injury would present with a cortical discontinuity on the medial aspect of the distal humerus near the attachment of the common flexor tendons. The line that is visualized in the radiograph in this area represents a developing apophysis rather than a fracture in this patient. Treatment consists of casting or open reduction internal fixation depending on displacement.

Answer 3: Radial head subluxation (also known as nursemaid elbow) occurs in younger patients who present after axial traction of the forearm. Patients present with elbow pain and refusal to move the elbow. A child with this condition may also present with lateral radial head pain but would be younger and would not have a visible fracture line in the area. Treatment is with closed reduction.

Answer 5: Supracondylar humerus fracture is the most common pediatric fracture that results from a fall onto an outstretched hand. These fractures may be occult and have no fracture line, but the pain is located over the distal humerus and would not be associated with a radial head fracture as seen in this case. Treatment is with casting or percutaneous pinning depending on displacement.

Bullet Summary:
Salter-Harris fractures involve the developing pediatric physis of a long bone and can be classified according to the involvement of the surrounding epiphysis or metaphysis.