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Topic:

Nursemaid Elbow

Issue:

Elbow

Category:

Trauma

Title:

The Relationship between the Bevel of the Radial Head Epiphysis and the Posterior Synovial Fringe During Rotation of the Elbow: An Ultrasonography Study with Possible Implications Regarding the Pathophysiology of Nursemaid’s Elbow

Author:

Tsai, Chia-Che MD; Chiang, Yi-Pin MD, PhD

Journal:

Journal of Pediatric Orthopaedics

Date:

February 2024

Reference:

44(2): p e131-e137, DOI: 10.1097/BPO.0000000000002550

Level Of Evidence:

III

# of Patients:

21

Study Type:

Diagnostic study

Location:

Not specified

Summary:

This study investigates the relationship between the posterior synovial fringe and the radial head epiphysis during elbow rotation to better understand the pathophysiology of nursemaid’s elbow.

Methods:

High-frequency linear array 6 to 24 MHz hockey stick ultrasound transducer was used to observe small morphological changes in the radial head epiphysis and the posterior synovial fringe during elbow rotation (pronation, neutral, and supination).

Exclusions:

Not specified

Results:

In complete pronation: The anterior edge of the posterior synovial fringe contacts the beveled articular surface of the radial head peripheral rim in all 21 patients. In neutral and complete supination: The anterior edge of the posterior synovial fringe contacts the nonarticular convex surface of the radial head peripheral rim and extends into the foveal radius. Tension in pronation: The posterior synovial fringe and the capsule-aponeurotic membrane were tightened during passive pronation in all 21 cases. Loose position in neutral and supination: Both the posterior synovial fringe and capsule-aponeurosis membrane were loose in neutral and supination positions.

Conclusions:

The study hypothesizes that the primary cause of nursemaid’s elbow is due to the interaction between the beveled peripheral rim of the radial head epiphysis and the anterior edge of the posterior synovial fringe, particularly when the elbow is in a pronated position. The tension caused by the lateral collateral ligament complex in pronation may lead to instability, contributing to the injury. This helps explain why nursemaid’s elbow predominantly occurs in the pronator position.

Relevance:

Limitations:

Perspective:

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