Specific injuries of the forearm and elbow
When evaluating elbow radiographs in pediatric practice, supracondylar humeral fracture (supracondylar fracture) is frequently identified. Its characteristic radiological signs include posterior displacement of the distal fragment (posterior displacement) and the presence of massive effusion in the joint cavity.
Combined forearm bone injuries require special vigilance:
- Monteggia fracture (Monteggia fracture): an isolated fracture of the ulna accompanied by dislocation of the radial head.
- Galeazzi fracture (Galeazzi fracture): a fracture of the distal radius combined with dislocation of the ulnar head.
Phalangeal injuries in preschoolers often present as crush injuries (crush injuries)—for example, in domestic settings when fingers are caught in a door. Fractures also occur from direct impact or the action of avulsion forces (avulsion forces) during wrist hyperextension. It is critically important for the diagnostician to locate the avulsed fragment: due to tendon retraction (tendon retraction), the fragment can migrate over a significant distance. Fractures of the distal scaphoid pole are evaluated radiographically, while MRI in the acute phase demonstrates high signal intensity on T2-weighted images and low signal intensity on T1-weighted images.
Pelvic ring and hip joint trauma
The multitude of pelvic fracture classifications stems from the necessity to accurately assess force vectors and predict the severity of consequences (morbidity).
- Severe injuries: occur as a result of high-energy impacts, lead to significant disruption of the pelvic ring, and are frequently associated with brain injuries. The primary diagnostic method here is computed tomography (CT) integrated into the initial screening protocol.
- Mild injuries: represented by avulsion fractures. They are typical for adolescent athletes, localize at muscle attachment sites, and are clearly visualized on standard anteroposterior radiographs.
Acetabular fractures in children are rare but dangerous. Involvement of the triradiate (triradiate) cartilage disrupts joint formation. CT or MRI is used to detect hidden injuries of the acetabular margins. Hip dislocations (posterior outnumbering anterior) in children rarely lead to acetabular fractures; however, their delayed reduction (24 hours or more) threatens the development of avascular necrosis of the femoral epiphysis.
Injuries of the femur and knee joint
Femoral head and neck fractures are classified according to their location: transepiphyseal, transcervical, cervicotrochanteric, and intertrochanteric. Potential complications include varus deformity, nonunion, premature closure of the physis (growth plate), and osteonecrosis (the risk increases with significant fragment displacement). Diaphyseal fractures frequently occur with considerable displacement due to the powerful traction of attached muscles; cross-sectional imaging (cross-sectional imaging) is preferred for an accurate assessment of rotational displacement.
Acute knee trauma in children does not always require diagnostic imaging. Pediatrics utilizes strict clinical decision rules for ordering radiographs. An imaging study is indicated if:
- There is isolated tenderness over the patella or the fibular head.
- The child is unable to flex the knee to 90 degrees.
- There is an inability to bear weight on the injured leg.
The protocol includes anteroposterior and lateral views, optionally supplemented by an axial patellar view (skyline view). Image analysis focuses on joint effusion, which obliterates fat planes and sharply outlines the suprapatellar space.
Briefly: answers to topical questions
In which specific anatomical structures do pelvic avulsion fractures localize in adolescent athletes?
Pelvic avulsion fractures in adolescent athletes localize in the region of apophyses where muscles attach. The most frequent anatomical structures are:
- Anterior superior iliac spine (spina iliaca anterior superior / anterosuperior iliac spine) — the attachment site of the sartorius muscle.
- Anterior inferior iliac spine (spina iliaca anterior inferior / anteroinferior iliac spine) — the attachment site of the rectus femoris muscle.
- Ischial tuberosity (tuber ischiadicum / ischial tuberosity) — the attachment site of the hamstring muscles.
Fractures may also localize in the region of the iliac crest (iliac crest), pubic symphysis (pubic symphysis), lesser trochanter (lesser trochanter), and greater trochanter (greater trochanter) of the femur.
Which radiological lines and angles are used to assess displacement in supracondylar humeral fractures?
The anterior humeral line is used to assess displacement in supracondylar humeral fractures.
- Anterior humeral line (anterior humeral line) — drawn along the anterior cortical margin of the humerus.
Normally, this line should intersect the capitellum (capitellum) of the humeral condyle, leaving at least its anterior third in front of the line. In a fracture with posterior displacement of the distal fragment, the line passes through the anterior third of the capitellum or fails to intersect it entirely. Angles for assessing this type of fracture are not described in the literature.
Which classification is used to evaluate traumatic growth plate (physis) injuries in children?
Traumatic growth plate injuries in children are evaluated using the Salter-Harris classification. It applies to open physes of tubular bones and includes 5 main and 4 additional types:
- Salter-Harris I — physeal slip (epiphysiolysis).
- Salter-Harris II — fracture through physis and metaphysis (the most frequent type).
- Salter-Harris III — fracture through physis and epiphysis.
- Salter-Harris IV — fracture through metaphysis, physis, and epiphysis.
- Salter-Harris V — crush injury of the physis.
- Salter-Harris VI — injury to the perichondral structures.
- Salter-Harris VII — isolated focal injury of the physis.
- Salter-Harris VIII — isolated metaphyseal injury sparing the physis.
- Salter-Harris IX — periosteal injury.
Class and exam questions
How to differentiate between Monteggia and Galeazzi fractures on a radiograph?
In a Monteggia fracture, the ulna is fractured and the radial head is dislocated, whereas in a Galeazzi fracture, conversely, the radius is injured and the ulnar head is dislocated.
Why is the bone fragment frequently not visible at the fracture site in an avulsion injury of a finger phalanx?
Due to tendon contraction (retraction), the bone fragment is pulled over a significant distance from its original attachment site.
Why are acetabular injuries dangerous in pediatric practice?
They can involve the triradiate cartilage, which subsequently leads to impaired normal growth and development of the acetabulum.
What else to study on this topic
- MRI semiotics of avascular necrosis of the femoral head
- Assessment of rotational displacement in diaphyseal fractures using CT
- Radiological signs of effusion in the knee and elbow joints
- Validated clinical decision rules (Ottawa Knee Rules) in pediatric traumatology
- Features of fracture healing involving the triradiate cartilage
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