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Difficulty: MediumOrthopedic Surgery

A 66-year-old girl is brought to the emergency department by her parents after falling from monkey bars onto her outstretched left hand 3030 minutes ago. She is crying and clutching her left arm. Vital signs show a temperature of 37.1∘37.1^\circ C, blood pressure of 105/65105/65 mmHg, heart rate of 115115/min, and respiratory rate of 2222/min. Physical examination reveals a significantly swollen left elbow with a prominent S-shaped deformity. The overlying skin is intact. Neurovascular assessment of the left upper extremity demonstrates a pale hand with a capillary refill time of 44 seconds. The radial pulse is not palpable but is faintly detectable via Doppler ultrasound. The patient is unable to make an "OK" sign with her left hand, but sensation over the palmar aspect of the first three digits is intact. Radiographs of the left elbow show a completely displaced, extension-type supracondylar fracture of the humerus. Which of the following is the most appropriate next step in management?

  1. Immediate closed reduction and percutaneous pinningAnswer
  2. B
    Computed tomography angiography of the left upper extremity
  3. C
    Open surgical exploration of the brachial artery
  4. D
    Application of a long-arm cast in 110∘110^\circ of flexion
  5. E
    Admission for arm elevation and serial neurovascular checks

Answer

Immediate closed reduction and percutaneous pinning is the most appropriate next step.
The correct response is immediate closed reduction and percutaneous pinning. This patient presents with a completely displaced, extension-type supracondylar humerus fracture complicated by vascular compromise (indicated by the pale hand, 44-second capillary refill, and absent palpable radial pulse). In these fractures, the proximal humeral fragment displaces anteriorly and can stretch, kink, or entrap the brachial artery and the median nerve (specifically its anterior interosseous branch, leading to the inability to flex the distal phalanges of the thumb and index finger to make an 'OK' sign). Because the ischemia is typically caused by anatomical kinking rather than true vessel transection, the mandatory first step is emergency closed reduction and percutaneous pinning. Realigning the fracture reliably restores arterial patency and distal perfusion in most cases.

Step-by-Step Solution

1
Identify the clinical diagnosis and associated complications from the vignette.
The patient has a completely displaced extension-type supracondylar humerus fracture. Complications include anterior interosseous nerve injury (inability to make an 'OK' sign) and severe vascular compromise (pale hand, delayed capillary refill, absent palpable pulse).
Recognizing signs of limb ischemia dictates the urgency of the intervention.
2
Determine the anatomical etiology of the vascular compromise.
The brachial artery and median nerve are being stretched or kinked over the sharp anterior edge of the displaced proximal humeral fragment.
Understanding the anatomical distortion explains why realignment of the bone is the primary treatment for the vascular deficit.
3
Select the most appropriate acute management for the ischemic limb.
Immediate closed reduction and percutaneous pinning.
Closed reduction realigns the bone, which directly relieves the kinking of the brachial artery and restores perfusion in the vast majority of cases without necessitating open vascular exploration.

Key Concept

The initial management of a displaced supracondylar humerus fracture with signs of vascular compromise is immediate emergency closed reduction and percutaneous pinning to relieve brachial artery compression and restore distal perfusion.
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Orthopedic Surgery

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