Mallet Finger on X-ray & MRI: Imaging Findings
Mallet finger is an injury to the terminal extensor tendon at the DIP joint. The tendon may tear without a visible fracture, or it may pull off a small piece of bone from the distal phalanx. X-rays are important because a large bony fragment or DIP subluxation can change treatment planning. MRI or ultrasound can show the tendon gap when the X-ray is normal but the fingertip cannot actively extend.
Common Symptoms
- Drooping fingertip after a ball strike, crush injury, or forced DIP flexion
- Inability to actively straighten the DIP joint while passive motion remains possible
- Pain, swelling, or bruising around the back of the fingertip joint
- Small bony fragment near the dorsal base of the distal phalanx on X-ray
What We Look For on Imaging
- Dorsal avulsion fracture at the base of the distal phalanx
- DIP joint flexion posture or volar subluxation of the distal phalanx
- Size of the articular fragment and percentage of joint surface involved
- Terminal extensor tendon discontinuity, thickening, or retraction on MRI
- Chronic swan-neck posture or degenerative DIP change on delayed imaging
Frequently Asked Questions
Why does a mallet finger usually need an X-ray?
The visible droop can come from a pure tendon tear or a bony avulsion. X-ray helps show whether the joint surface is involved and whether the DIP joint remains aligned. Those details affect splinting strategy and whether a hand specialist should review the injury urgently.
Can AI tell whether a mallet finger needs surgery?
Treatment depends on joint alignment, fracture size, skin condition and examination, with many closed injuries managed by splinting. AI cannot decide whether surgery is needed.
Sources
- Bendre AA, Hartigan BJ, Kalainov DM. Mallet finger. J Am Acad Orthop Surg. 2005;13(5):336-344.
- Salazar Botero S, Hidalgo Diaz JJ, Benaïda A, et al. Review of acute traumatic closed mallet finger injuries in adults. Arch Plast Surg. 2016;43(2):134-144.
- Husain SN, Dietz JF, Kalainov DM, Lautenschlager EP. A biomechanical study of distal interphalangeal joint subluxation after mallet fracture injury. J Hand Surg Am. 2008;33(1):26-30.
- Clavero JA, Alomar X, Monill JM, et al. MR imaging of ligament and tendon injuries of the fingers. Radiographics. 2002;22(2):237-256.
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Medical Disclaimer: This page is for informational and educational purposes only. It does not constitute medical advice, diagnosis, or treatment. AI-generated analysis may contain errors. Always consult a qualified healthcare professional for medical decisions. Full Disclaimer