Scotland ST1 Orthopaedic National Selection Preparation

Supracondylar fractures of the humerus are the most common elbow injury in children, typically occurring after a fall onto an outstretched hand. They are clinically significant due to the risk of neurovascular injury and long-term deformity if not managed appropriately. For the interview it is worth knowing the relevant anatomy, assessment of the injury and neuromuscular status and also long term complications. 

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General Approach

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example scenario:  You are called to A&E to see 10 year old male who has fallen off a trampoline and is complaining of a painful left elbow and following XR.

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This would still fall into the category of high impact injury so still start your answer with the ATLS approach + AMPLE history taking. Because supracondylar fractures are mainly in kids, its also really important to be vigilant of NAI. Like any scenario where a fracture is involved , Investigate for neurovascular status and whether it is a closed injury. 

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How to investigate the NVI of Upper Limb (especially in this scenario)? 

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It becomes important to have an understanding of the anatomy, particularly the median nerve and its branch, the anterior interosseous nerve (AIN), which are vulnerable in supracondylar fractures. The median nerve descends with the brachial artery and gives off the AIN just distal to the elbow. The AIN is a purely motor branch supplying flexor pollicis longus, the radial half of flexor digitorum profundus, and pronator quadratus (deep layer of muscular anterior forearm). Because of its isolated motor function, injury is often missed unless specifically tested with the “OK sign” (inability to pinch with thumb and index).

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A practical way to assess the nerves of the upper limb in this setting is the “rock, paper, scissors, thumbs-up” test:

• Rock (fist flexion) → Median nerve

• Paper (wrist extension / flat hand) → Radial nerve

• Scissors (V-sign / finger abduction/adduction) → Ulnar nerve

• OK sign → AIN

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

You will also have to complete an assessment of the vascular status of the limb. These can be measured by CRT (capillary refill time) and in severe cases using a ABPI cuff, doppler or even CTA. There are 3 broad categories in which the vascular status can can fall into: 

1. Pulse and Pink 

2. Pulseless and Pink 

3. Pulseless and Pale.

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Before moving on to the management of the pulseless fracture. It is worth knowing the Gartland classification of fracture: 

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Gartland Classification of Supracondylar Fractures

• Type I – Undisplaced or minimally displaced (<2 mm) with the anterior humeral line intact.

• Type II – Displaced >2 mm; anterior humeral line no longer passes through the centre of the capitellum, but posterior cortex remains in contact.

• Type III – Completely displaced with torn periosteum and no cortical contact.

• Type IV (modified) – As Type III but unstable in both flexion and extension due to complete periosteal disruption.

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1. Pale, pulseless hand

• Seen in ~10–20% of Gartland III fractures.

• Indicates poor collateral supply (true ischaemia).

• Management: Immediate reduction and percutaneous pinning.

• Pulse usually returns (≈75%) due to spasm or entrapment.

• If still absent → urgent open vascular exploration.

• This is a true emergency.

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2. Pink, pulseless hand with nerve injury

• Hand is perfused by rich collateral supply despite absent pulse.

• Nerve injury may suggest vascular tethering at fracture site.

• Management: Urgent (but not always emergent) reduction and pinning.

• If pulse not restored, consider early vascular exploration.

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If there is any concern about NVI or any patient that is likely to require urgent surgery, at the level of ST1 you should mention that you will discuss with a senior.