SNAC Wrist (Scaphoid Nonunion Advanced Collapse)

SNAC wrist (Scaphoid Nonunion Advanced Collapse) is a pattern of wrist arthritis that develops when a scaphoid fracture fails to heal properly.

The scaphoid plays a key role in stabilising the wrist. When it does not unite after a fracture, abnormal motion occurs between the wrist bones. Over time, this leads to uneven loading and progressive wear of the joint surfaces.

SNAC wrist follows a predictable pattern of joint degeneration, typically beginning between the scaphoid and radius before progressing to involve other parts of the wrist.

Symptoms often develop gradually and may worsen over months or years following the original injury.

Early diagnosis and appropriate management can help slow progression and preserve wrist function.

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Diagnosis is based on clinical assessment and imaging.

Investigations may include:

• X-rays to assess joint alignment and signs of arthritis
• CT scan to evaluate the scaphoid nonunion
• MRI scan in selected cases to assess bone viability

These investigations help determine the stage of the condition and guide treatment decisions.

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Treatment depends on the stage of arthritis and the severity of symptoms.

Non-surgical treatment may include:

• Activity modification
• Wrist splinting
• Anti-inflammatory medication
• Hand therapy to maintain movement and strength

Surgical treatment may be recommended if symptoms persist and can include:

• Fixation and bone grafting of the scaphoid (in selected cases of nonunion)
• Proximal row carpectomy (removal of damaged wrist bones)
• Partial wrist fusion to reduce pain while preserving some motion
• Total wrist fusion in advanced cases to eliminate pain

The aim of treatment is to relieve pain, improve function, and slow progression of arthritis.

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Surgical treatment is tailored to the stage of the condition and patient needs.

In earlier cases, surgery may aim to restore scaphoid healing. In more advanced stages, procedures focus on relieving pain and improving function by addressing arthritic changes.

Surgery is typically performed as a planned procedure, often under regional or general anaesthetic.

Recovery depends on the type of treatment performed.

Recovery may include:

• Immobilisation in a splint or cast
• Gradual rehabilitation with hand therapy
• Strengthening exercises as healing progresses

Improvement in pain and function is expected over time, although full recovery may take several months.

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As with any surgical procedure, there are potential risks, although these are uncommon.

Possible complications include:

• Infection (usually treated with antibiotics)
• Ongoing pain or incomplete symptom relief
• Stiffness or reduced wrist movement
• Nerve irritation or sensitivity
• Nonunion or delayed healing (in reconstructive procedures)
• Failure of the procedure or progression of arthritis over time

Your surgeon will discuss the specific risks and expected outcomes based on the procedure recommended.

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You should seek medical advice if you have persistent wrist pain following a previous injury, particularly if symptoms have gradually worsened over time.

Early assessment is important, as untreated scaphoid fractures can lead to long-term joint damage and reduced function.

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