Courtesy: Sandeep Patwardhan, Ashok Shyam, Sancheti Institute, Pune and IORG, OrthoTV

 

TRASH Lesions of the Elbow in Children

Definition

TRASH = “The Radiographic Appearance Seemed Harmless.”

A swollen, painful pediatric elbow with a seemingly normal or minimally abnormal X-ray may actually have a significant occult injury.

Why They Are Important

• These injuries are commonly missed.
• Missed injuries can lead to malunion, elbow stiffness, instability, and long-term disability.
• “Eyes don’t see what mind doesn’t know.”

Clinical Scenario

• Child with a fall on the elbow or hand.
• Pain, swelling, and restricted elbow movement.
• X-ray appears normal or shows only subtle findings.

Commonly Missed TRASH Lesions

Radial Head / Neck Injuries

• Osteochondral fractures.
• Radial head subluxation or dislocation.
• Important clue: abnormal radiocapitellar alignment.
• The radial head ossifies at approximately 5 years and may therefore be invisible on X-ray in younger children.

Medial Condyle Fracture

• May be mistaken for a medial epicondyle fracture.
• A small metaphyseal fragment may represent a much larger cartilaginous component that is not visible on X-ray.
• In a child younger than 9 years, consider a medial condyle fracture unless proven otherwise.
• Complications include cubitus varus and elbow stiffness.

Transphyseal Distal Humerus Separation

• Usually seen in children younger than 3 years.
• The radius and ulna move together.
• Radiocapitellar alignment is maintained.
• Medial displacement may occur.
• Can be mistaken for an elbow dislocation.

Missed Monteggia Lesion

• Ulna fracture associated with radial head dislocation.
• Always assess the radiocapitellar line.
• Missed diagnosis may result in chronic deformity requiring later osteotomy.

Occult Lateral Condyle Fracture

• May initially appear subtle.
• A metaphyseal flake may be visible.
• The fracture may extend into the joint.
• Displacement can lead to nonunion.
• MRI or arthrogram may help establish the diagnosis.

Capitellar Shear Fracture

• Seen more commonly in older children.
• Best appreciated on the lateral X-ray.

Osteochondral Sleeve Fractures

• May cause posterolateral instability.
• Recurrent subluxation can occur despite a normal X-ray.

Entrapped Medial Epicondyle

• May occur following elbow dislocation.
• Look for a missing medial epicondyle and joint incongruity.
• The fragment may become trapped within the joint.
• The ulnar nerve may also become entrapped.

Diagnosis

Stepwise Approach

• Maintain a high index of suspicion.
• Check the radiocapitellar line.
• Check the anterior humeral line.
• Compare with the opposite elbow when necessary.
• Look carefully for fat pad signs.
• Assess soft-tissue swelling patterns.

Additional Imaging

• MRI: Best for cartilage and occult injuries.
• Arthrogram: Demonstrates joint congruity and intra-articular anatomy.
• Ultrasound: Operator dependent.
• CT: Provides better bony detail.

Management

• The source states that most TRASH lesions are surgical, approximately 90%.
• Treatment may involve closed or open reduction.
• Fixation may be performed with K-wires or screws.

Red Flags

• Swollen elbow + normal X-ray – normal elbow.
• In children younger than 5 years, absent ossification centers can hide fractures.
• A presumed medial epicondyle fracture in a young child should raise suspicion for a medial condyle fracture.
• An apparent elbow dislocation in a child younger than 3 years should raise suspicion for a transphyseal injury.
• Always check radiocapitellar alignment.

CRITOE – Ossification Centers

• C – Capitellum -1 year.
• R – Radial head – 3 years.
• I – Internal/medial epicondyle – 5 years.
• T – Trochlea – 7 years.
• O – Olecranon – 9 years.
• E – External/lateral epicondyle – 11 years.

Exam Pearls

• TRASH = The Radiographic Appearance Seemed Harmless.
• Small bony fragment may represent a large cartilage injury.
• Medial epicondyle-looking fracture in a young child – think medial condyle.
• Very young child + apparent elbow dislocation – think transphyseal injury.
• Monteggia – always check the radiocapitellar line.
• Swollen painful elbow with a normal X-ray –  investigate further.
• If clinical findings do not match the X-ray, do not dismiss the injury.