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The medial epicondyle-ulnar nerve relation with various elbow positions in healthy children
Yakup Yıldırım1, Motasım Bawaneh, Tevfik Balıkçı
1School of Medicine, Marmara University, İstanbul, Turkey.
Insights
Elbow flexion significantly moves the ulnar nerve closer to the medial epicondyle in children. This proximity may increase the risk of ulnar nerve injury during supracondylar humerus fracture treatment.
Area of Science:
- Pediatric Orthopedics
- Ultrasound Imaging
- Nerve Anatomy
Background:
- Understanding ulnar nerve positioning is crucial for pediatric elbow fracture management.
- Elbow flexion and forearm rotation are common maneuvers during supracondylar humerus fracture reduction.
Purpose of the Study:
- To determine the position of the ulnar nerve relative to the medial epicondyle in healthy children.
- To assess the impact of elbow flexion and forearm position on this relationship.
Main Methods:
- High-resolution ultrasonography was used to evaluate 76 elbows in 38 healthy children (aged 4-12).
- Measurements of the medial epicondyle-ulnar nerve distance were taken with varying degrees of elbow flexion and forearm pronation/supination.
- Statistical analysis included one-way ANOVA and paired t-tests.
Main Results:
- Ulnar nerve anterior translation was observed with increasing elbow flexion.
- The mean distance decreased from 3.7 mm (extended elbow) to 1.1 mm (fully flexed elbow), a statistically significant difference (P<0.0001).
- Forearm position (pronation/supination) and child's age/sex did not significantly affect this distance.
Conclusions:
- Elbow flexion significantly reduces the medial epicondyle-ulnar nerve distance in children, irrespective of forearm rotation.
- This close proximity in a flexed position may pose a risk to the ulnar nerve during medial pinning for supracondylar humerus fractures.
Background:
The position of the ulnar nerve relative to the medial epicondyle in healthy children was determined with a high-resolution ultrasonography with elbow flexion, forearm pronation, and supination maneuvers which are commonly employed during reduction of the supracondylar humerus fractures.
Methods:
Healthy children aged between 4 and 12 years were enrolled in this study. Both elbows of the children were evaluated with a high-resolution sonography device with gradual flexion of the elbow, whereas the forearm is alternately in pronation and supination. The medial epicondyle-ulnar nerve distance was measured with the various positions of the elbow and the forearm. One-way analysis of variance was used to analyze the differences of medial epicondyle-ulnar nerve distance at different elbow flexion angles and forearm supination-pronation positions. Paried t test was used to compare the differences between the age and sex of the children.
Results:
Twelve female and 26 male children (76 elbows) with a mean age of 8.36 years were included in the study. Ulnar nerve was translated anteriorly through the medial epicondyle with increasing elbow flexion. The mean medial epicondyle-ulnar nerve distance that was 3.7 mm in an extended elbow decreased to 1.1 mm with full elbow flexion. The difference was statistically significant (P<0.0001). Presence of the forearm in either supination or pronation did not produce a statistically significant difference. The age and sex of the children did not produce a statistically significance difference in medial epicondyle-ulnar nerve distance.
Conclusions:
Flexion of the elbow brings the ulnar nerve to a close proximity to the medial epicondyle independent of forearm pronation and supination in healthy children. The decrement of the medial epicondyle-ulnar nerve distance up to 1.1 mm in a fully flexed elbow might be a factor that endangers the nerve during medial pinning in supracondylar humerus fractures.
Level Of Evidence:
Level I-diagnostic studies.
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