14-year old Noah was rocking on his chair while daydreaming his way through a maths lesson this morning… and fell off. He reports that he landed directly on his left elbow and that it has been painful throughout the day. He attends your ED this afternoon with his unamused mother.
Assessment of any child and examination of their elbow should be approached in an age-appropriate and systematic way. In addition to examining for bony tenderness, vascular and neurological status should be tested.
You ensure Noah has been given analgesia before examining him. His pain score is 5 and he seems comfortable after paracetamol and ibuprofen when his arm is resting. His elbow is notably bruised and swollen. He is particularly tender over the olecranon and any movement is painful. His neurovascular status is normal with good radial and ulnar pulses, normal sensation in the radial, ulnar and median nerve distributions and as he’s able to make the rock, paper, scissors and ok hand signs, you’re happy he has full motor function. You order AP and lateral films of his elbow and pop him in a broad arm sling for comfort before sending him round for his x-rays.
Epidemiology and mechanism of injury
Olecranon fractures in children are rare, comprising around 5% of elbow fractures. Compare this with supracondylar fractures which comprise over half of all elbow fractures in the paediatric population. Olecranon fractures may result from a fall onto an outstretched hand (FOOSH), direct trauma or, occasionally, a stress fracture from repetitive throwing motion in athletes.
They can be classified according to the Mayo classification.
In addition to pain, there will almost certainly be generalised swelling around the elbow, usually with visible evidence of trauma, such as bruising or abrasion, over the olecranon process. Point tenderness over the olecranon is often a feature, but the degree of swelling can sometimes make this difficult to appreciate. Inability to fully extend the elbow is common, and pain on extension, supination and pronation is expected. In those with comminuted or significantly displaced fractures it may be possible to feel crepitus over the olecranon.
Interpreting children’s elbow x-rays can be mind boggling. Epiphyses ossify at different rates and so it can be easy to confuse a normal olecranon epiphysis with a fracture. The olecranon epiphysis normally appears around 9 years and fuses at 15-17 years. Be sure to refer to the CRITOE rules and if you’re not sure whether you’re seeing a normal epiphysis or a fracture, seek senior advice. The olecranon can be best assessed on the lateral film.
This x-ray shows a normal olecranon epiphysis:
Some olecranon fractures are obvious…
…but some can be incredibly subtle as illustrated in this series from Radiology Assistant:
Some olecranon fractures may only be visible on one view. This may be the AP or the lateral. The below elbow x-rays show a transverse olecranon fracture visible on the AP view only (arrow). Note the raised anterior and posterior fat pads on the lateral view. And an extra bonus point to those who spotted the subtle radial neck fracture.
The majority of olecranon fractures (around 80%) are either undisplaced or minimally displaced (less than 2mm); these can be managed conservatively with an above elbow back-slab with good functional outcome.
In children with a displaced olecranon fracture, there is risk of complications including delayed or non-union, ongoing elbow stiffness and impaired function. Refer any child who has an olecranon fracture with these features as they’re likely to require surgical intervention:
- >2-4mm displacement
- angulation of >30°
- intra-articular involvement
- extensor mechanism disruption
- instability on extension
The practitioner seeing injured children in the ED must be aware of the potential for these. Displaced olecranon fractures can cause growth disturbances resulting in fixed flexion deformity of the elbow joint and associated morbidity into adulthood.
The ulnar nerve is particularly at risk of injury with olecranon fracture. Ensure you carry out a thorough neurovascular assessment, in particular checking sensation over the little finger and that the small muscles of the hand are functioning normally (the “scissors” sign).
A significant proportion of olecranon fractures are associated with concomitant injury, including radial neck fracture and /or supracondylar fracture and any co-existing injury is prognostic for poorer outcome. When interpreting the x-ray, it is important therefore to have a systematic approach.
Bullets of wisdom
- Don’t confuse an unfused olecranon epiphysis with a fracture
- But don’t forget that olecranon fractures can be subtle – maintain a high index of suspicion in children with direct trauma and inability to extend their elbow
- Olecranon fractures are sometimes only visible on one view and this can be the lateral or the AP
- Displaced fractures can have devastating consequences and must be referred to orthopaedics as they may need surgical intervention
- Document neurovascular status and be sure to check ulnar nerve function
- And look for a concomitant radial neck or supracondylar fracture
Noah returns from X-Ray and you review his films. He has a posterior fat pad sign and on closer scrutiny you spot an intra-articular fracture of the olecranon. You recognise that this type of fracture can be associated with complications and refer him to the orthopaedic team. You ensure that his pain score and neurovascular status are being assessed regularly.
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