Aisha is 10 years old. She loves gymnastics but today, during a cartwheel, she injured her right elbow. Aisha is cradling her right arm in her left hand and is reluctant to move it, despite having had ibuprofen at home.
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.
On examination, you note swelling around the elbow, especially on the lateral aspect. Aisha has tenderness particularly over the radial head and complains of pain on any movement especially supination and pronation. She has normal sensory and motor function of radial, ulnar and median nerves and normal pulses, colour and capillary refill time to her hand. You prescribe further analgesia, apply a broad arm sling for comfort and order lateral and AP x-rays of her elbow.
Radial head and neck fractures comprise around 5% of all elbow injuries in children, with a peak at 9-10 years of age. They normally result from a FOOSH (‘fall onto an outstretched hand’). Fractures through the radial head are rare in children: more commonly the physis (the growth plate: the disc of cartilage between the epiphysis and metaphysis), or radial neck will be involved.
Radial Neck fractures
Radial neck fractures can generally be diagnosed on lateral and AP elbow x-ray. It’s useful to remind yourself of the elbow anatomy prior to looking at the x-ray so that you know what you’re looking for. It’s really important to appreciate that part of the radial neck sits outside of the capsule. Most radial neck fractures occur at the level of the annular ligament, which forms a collar around the radial neck to anchor it to the ulna.
This means that not all radial neck fractures have a joint effusion. Don’t be fooled by a lateral elbow x-ray without a fat pad sign – this just means there’s no joint effusion; it doesn’t mean there isn’t a radial neck fracture.
The appearance can be quite subtle, so it’s useful to remind yourself what the radial neck looks like on a normal X-ray:
In particular, notice how the contours of the radial neck form smooth curves, as above. These smooth curves are lost in radial neck fracture:
How are radial neck fractures classified?
Radial neck fractures were classified by O’Brien (1965) as follows:
Type I: <30 degrees displacement
Type II: 30-60 degrees displacement
Type III: >60 degrees displacement
O’Brien’s classification of radial neck fractures. From Orthobullets
Other radial neck classifications have been described so, to avoid confusion, it’s probably safest to describe the degree of displacement rather than the classification type, especially as displacement of radial neck fractures in children is uncommon.
How should radial neck fractures be managed?
Most paediatric radial neck fractures are type I: undisplaced or minimally displaced. These do really well with conservative management with immobilization in a collar and cuff. Those with displacement of >30 degrees tend to have a worse outcome and should be referred to orthopaedics as reduction, and possible internal fixation will be required.
Which children need to be discussed with the orthopaedic team before they go home?
- Any displaced radial neck fractures
- Any radial neck fractures with a second elbow injury
Radial neck fractures – do not miss…
30-50% of children with a proximal radial fracture have another fracture – examine the child and their x-rays very carefully. Having a second injury is associated with a poorer outcome. The most common associated injuries are:
- elbow dislocations
- medial epicondyle fractures
- olecranon fractures
Radial neck fractures can also be associated with compartment syndrome of the forearm, although thankfully this is rare. Compartment syndrome is a limb-threatening condition caused by increased pressure within the closed space of a muscular compartment which causes compression of the nerves, muscles, and vessels within the compartment. Untreated, this can lead to ischaemic injury within 4-8 hours.
Assessing for compartment syndrome – the 5 Ps
- Pain – the most important indicator. Often diffuse and progressive, not resolved by analgesia, worsened by passive flexion of the injury.
- Pallor – assess distal to the injury. Dusky or cool skin (compared to the other side) or delayed capillary return.
- Pulse – weak or absent pulse indicates poor perfusion,
- Paralysis – assess active movement of the wrist and fingers. This may cause pain but the purpose is to assess ability to move.
- Paraesthesia – ask about pins and needles or a feeling of the hand “falling asleep”. Assess sensation with light touch or using an object such as a pen lid.
Any concerns about potential compartment syndrome must be escalated to an ED or orthopaedic senior without delay as this is a time-critical situation.
Radial Head fractures
Like radial neck fractures, radial head fractures are also most often due to a FOOSH. Unlike radial neck fractures, radial head fractures typically occur after the proximal radial physis has closed so are more common in older children. They are usually clearly visible on x-ray and the majority are undisplaced and respond well to conservative management in a collar and cuff or sling. Displaced fractures of the radial head are rare and will need an urgent orthopaedic referral.
Aisha returns from X-Ray and you spot an undisplaced fracture of the radial neck, visible on the AP and lateral views. You remember that associated fractures are common and so have a careful look for other injuries and check the epiphyses using the CRITOE rule. Aisha has an isolated, non-displaced radial neck fracture with no other injuries: you pop her in a collar and cuff and organize virtual fracture clinic follow up. You make sure to give her and her family advice about analgesia and signs of any neurovascular compromise before they leave.
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