Natasha, a 13-year-old girl, attends the Emergency Department with pain in her right wrist after falling onto her outstretched hand while ice skating. There is minimal swelling, but she is reluctant to move the wrist.
She is tender on palpation of the anatomical snuffbox and on telescoping of the thumb.
A senior colleague suggested that this could be a scaphoid fracture and advised some plain radiographs. These show no bony injury, so she is placed in a wrist splint and referred for outpatient follow-up with the orthopaedic surgeons.
What is the scaphoid?
The scaphoid lies between the proximal and distal rows of carpal bones on the radial side of the wrist. Its name comes from the Greek ‘skaphos’, meaning boat, due to its boat-like shape. It starts to ossify between the ages of four and six years, forming two poles (proximal and distal) united by the waist. Ossification occurs from the distal pole and moves proximally. During ossification, it is protected by cartilage. The scaphoid receives its blood supply from the branches of the radial artery, but due to retrograde flow, the blood supply can be interrupted when the bone is fractured, risking avascular necrosis. Full ossification is usually complete by age 13 in girls and 15 in boys.
How common is scaphoid fracture in children?
Scaphoid fractures are uncommon in young children due to the protection of the bone during its ossification by a thick layer of cartilage and soft tissue. Cartilaginous fractures are possible but require reasonable force; simple soft tissue injuries are more common in younger age groups. Bony scaphoid fractures are seen predominantly in older children (ages 12-15). Any fracture diagnosed in the presence of growth plates seen elsewhere on radiographs is classified as a paediatric fracture.
Mechanism of Injury
The injury pattern for scaphoid fractures is similar to that of adults, with the typical presentation being a fall onto an outstretched hand. Scaphoid fractures may also result from punching against resistance. This injury should also be considered in higher impact trauma, where the wrists are forcefully hyperextended against resistance; a child putting their arms out against a dashboard or front seat in the context of a car accident may lead to scaphoid fracture.
Examination Findings
As with any orthopaedic examination, it is time to use the principle of look, feel and, finally, move.
In addition to examining the distal radius and ulna, any wrist examination should consider the scaphoid as the area of injury.
Although there is no positive finding which is pathognomonic of a scaphoid fracture, there are clues which should increase our clinical suspicion (see below)
Tenderness in the anatomical snuffbox – located in the first web space.
Tenderness of the scaphoid tubercle – located on the proximal palm at the base of the thumb
Pain is elicited by axial loading or ‘telescoping’ of the thumb.
Bear in mind that other injuries may be present.
Children can be difficult to assess, and if they are behaving as though they have a fracture, it can be difficult to rule out anything based on examination alone. Have a low threshold for imaging an area in which you are suspicious of a bony injury.
Imaging:
NICE recommends MRI as the first-line imaging modality in suspected scaphoid fractures. MRI is not only expensive, but most emergency departments have restricted access to this investigation. Plain radiographs miss up to 25% of scaphoid fractures across all age groups (Pincus, 2009), but this is our most readily available test.
A scaphoid series of plain X-rays includes four views: posteroanterior (PA), pronated, lateral, and supinated. A further view, PA with a clenched fist, allows some assessment of the scapholunate ligament integrity. Although soft tissues cannot reliably be assessed on plain radiographs, a widened space between the scaphoid and lunate may suggest ligamentous disruption.
Plain X-rays are very specific – the presence of a cortical interruption or trabecular abnormality is highly likely to represent a true fracture. However, a normal radiograph is not sensitive enough to rule out a fracture. Patients with normal radiographs, in the presence of clinical symptoms or signs suggestive of a fracture, should be treated as such and require further imaging, either in the form of repeat films 10-14 days post-injury or an early MRI.
Fracture Patterns in Children:
Due to the scaphoid ossifying from the distal pole proximally, this is the most likely part of the bone to fracture first in children (Gajdobranski, 2014). Unlike in adults, the middle and proximal parts of the bone are less frequently encountered. Similar to other fractures in paediatric patients, scaphoid fractures in this younger age group may be incomplete (uni-cortical) or non-displaced.
Management:
There is some overlap in the management in of suspected and confirmed scaphoid fractures based on the initial x-ray.
Paracetamol, ibuprofen and elevation in a sling are all appropriate while waiting for radiology.
If a confirmed fracture is seen on the patient’s initial imaging, a scaphoid cast can be applied. This is a below-elbow backslab with a thumb spica. These patients should be referred to the fracture clinic for further management.
Normal plain radiographs do not exclude a fracture. In this instance, a wrist splint is appropriate to immobilise the affected area. There is no evidence for splinting with the thumb in extension (Dawson-Bowling, 2014). These patients need to be brought back to the fracture clinic for repeat radiography or more advanced imaging in the form of MRI, dependent on local protocols.
Most scaphoid fractures in children and teenagers are managed conservatively with a cast. Whilst immobilisation time is usually the final remit of the orthopaedic surgeons, it is helpful to be able to offer children and their parents some advice in the Emergency Department as to how long healing will take. As a rule, the more distal the fracture, the quicker the healing process. This is in part due to the scaphoid’s blood supply. Longer immobilisation times will be needed for middle and proximal fractures.
Occasionally, surgical fixation will be required for significantly displaced fractures or in cases of non-union. This is beyond the scope of Emergency Department management.
Do not miss scaphoid fractures on wrist x-rays – don’t be distracted by other, more obvious fractures. This patient complained of distal forearm pain, but the scaphoid region was not specifically examined. A distal radius fracture and an ulnar styloid fracture were spotted on the x-ray. But, if you look at the very top of the film, you’ll also see a fracture through the scaphoid. Children may not complain of pain exactly over the fracture site, especially when there are fractures elsewhere.
Case Resolution
Natasha is seen in the fracture clinic ten days after her injury. Her splint is removed, and while the swelling has improved, her range of motion is still restricted by pain, and she remains significantly tender in the anatomical snuffbox.
She is booked for an MRI of the wrist, which shows a non-displaced fracture line through the distal pole of the scaphoid. She is placed into a scaphoid plaster cast and remains immobilised for a total of six weeks. When the cast is removed, she has no residual symptoms and makes a full, uncomplicated recovery.
Selected references
Abbasi D. Scaphoid Fracture. Orthobullets. Website. Available from: https://www.orthobullets.com/hand/6034/scaphoid-fracture[Accessed 20 April 2019]
Dawson-Bowling S, Achan P, Briggs T, Ramachandran M. 2014. Orthopaedic Trauma. The Stanmore and Royal London Guide. CRC Press.
Elhassan B, Shin A. Scaphoid Fracture in Children. Hand Clinics. 2006; 22(1):31-41
Gajdobranski D, Živanović D, Mikov A, et al. Scaphoid Fractures in Children. Srp Arh Celok Lek. 2014; 142(7-8):444-449
Ghane M, Rezaee-Zavareh M, Emami-Meibodi M et al. How Trustworthy Are Clinical Examinations and Plain Radiographs for Diagnosis of Scaphoid Fractures? Trauma Monthly. 2016; 21(5): 1-6
National Institute for Health and Care Excellence (2016) Fractures (non-complex): assessment and management (NICE Guideline 38). Available at: https://www.nice.org.uk/guidance/ng38 [Accessed 12 April 2019]
Jenkins P, Slade K, Huntley J et al. A comparative analysis of the accuracy, diagnostic uncertainty and cost of imaging modalities in suspected scaphoid fractures. Int. J. Care Injured. 2008; 39: 768—774
Pincus S, Weber M, Meakin A. Introducing a Clinical Practice Guideline Using Early CT in the Diagnosis of Scaphoid and Other Fractures. Western Journal of Emergency Medicine. 2009; 4: 227-232(BET 2: Do wrist splints need to have a thumb extension when immobilising suspected scaphoid fractures?Emerg Med J 2011;28:1075-1076.
