Refer to Orthopedic Hand Surgery—Do Not Order CT
For a complete UCL tear (gamekeeper's thumb), you should refer directly to an orthopedic hand surgeon without obtaining a CT scan, as CT has limited utility for soft tissue ligament injuries of the hand. 1
Why CT is Not Indicated
The ACR Appropriateness Criteria explicitly state that CT has limited use for the diagnosis of soft-tissue injuries of the hand 1. CT is reserved for evaluating bony structures and complex fractures, not ligamentous injuries. In your case with a suspected complete UCL tear, CT will not provide the diagnostic information needed and will only delay definitive treatment.
The Appropriate Imaging Algorithm
If you need imaging confirmation before referral (though clinical examination is often sufficient):
- MRI of the hand is the gold standard, with 100% sensitivity and specificity for UCL tears 1
- Ultrasound can identify Stener lesions (the critical complication where the adductor aponeurosis becomes interposed between the torn ligament and its insertion site) 1
However, imaging should not delay surgical referral when clinical examination demonstrates significant joint laxity.
Why Immediate Surgical Referral is Critical
Complete UCL tears require surgical intervention, particularly when:
- A Stener lesion is present (occurs in displaced complete tears)
- There is significant joint laxity on valgus stress testing with no firm endpoint at 30° of MCP flexion 2, 3
- The patient presents acutely (within 2 weeks) 2
The 2024 British Society for Surgery of the Hand guideline recommends that patients with significant joint laxity should reach a shared decision about definitive treatment within 2 weeks of presentation 2. Delaying with unnecessary imaging like CT wastes this critical window.
Clinical Decision Point
Your clinical examination findings are sufficient:
- Complete tear suspected = immediate hand surgery referral
- Partial tear with firm endpoint = may consider non-surgical treatment with thumb spica immobilization 3, 4
Common Pitfall to Avoid
Do not order CT imaging for soft tissue ligament injuries of the hand—this is a common error that delays appropriate care. The ACR guidelines are unequivocal that CT is not indicated for this clinical scenario 1. If you need imaging confirmation, order MRI or arrange for ultrasound evaluation by the hand surgeon, but prioritize getting the patient to the specialist quickly to optimize surgical outcomes and prevent chronic instability.