Scaphoid Fracture

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Epidemiology

Seen in teenagers and adults.

Clinical Assessment

Scaphoid fracture usually results from fall onto an outstretched hand, and there may be relatively little pain.

The three commonly used special tests are anatomical snuff box tenderness, scaphoid tubercle tenderness, and pain on axial compression of the thumb. The sensitivity for the three individual tests is 100%, with specificity of 74% if all three are positive. Pain on axial compression is the weakest test.

Imaging

The international standard appears to be early MRI in the presence of clinical features and a normal radiograph, or CT if MRI is not available. In New Zealand neither of these imaging modalities is available in primary care. MRI is preferred due to to its superior sensitivity and sensitivity, and also as it can pick up other injuries.

In some areas there may be rapid access to a specialist clinic. Otherwise the patient should be offered a private MRI.

Treatment

The lack of availability of MRI or CT in primary care in New Zealand has implication on management. If the patient is not able to access early MRI, the standard practice is treat any FOOSH injury with scaphoid tenderness in spite of a normal radiograph as a possible fracture, and immobilise in POP for 10 days.

If there is no MRI available then review in 10-14 days and organise a follow up x-ray.

The initial immobilisation method of a diagnosed fracture is either a split scaphoid cast or a backslab. There should be slight palmar flexion and radial deviation. Do not include the thumb

lab. Have slight palmar flexion and radial deviation - the thumb is not included.

Further management depends on the type of fracture:

• Mid-waist or distal fracture: Below elbow cast without the thumb. At one week change to fibreglass if POP was used initially. At 6 weeks remove the cast and x-ray. If the patient is still uncomfortable then request a CT to assess healing.
• Scaphoid tubercle fracture: Below elbow cast for 4-5 weeks for comfort. Non-urgent orthopaedic assessment is recommended.
• Proximal scaphoid fracture: Consider surgery if displacement of 1mm or more

If there is a partial scapholunate ligament injury or extrinsic dorsal ligamentous injury then treat with a compression bandage and refer for physiotherapy for splinting and rehabilitation.

If there is complete scapholunate ligament rupture (scapholunate dissociation) then refer to orthopaedics for consideration of surgery. In this condition there is a gap between the scaphoid and lunate of ≥ 3 mm. A clenched fist view can be used to confirm.

Hand physiotherapy should be offered following scaphoid injuries.

Prognosis

Incorrect management can lead to delayed union, non-union, or avascular necrosis. Delayed union or non-union is usually due to delayed or inadequate stabilisation, but can also be due to fracture instability.

Further Reading

• Clementson et al 2020.