Discontinuities of the extensor insertion are often referred to as “mallet
injury” or “baseball finger”. They can be purely tendinous, or bony avulsion
Diagnosis is based on
- The clinical history of the trauma
- Deformity, pain and swelling located in the dorsal aspect of the DIP
- Inability actively and fully to extend the DIP joint
AP and true lateral x-rays of the DIP joint are necessary for the diagnosis
of fracture avulsions.
Low-energy radiographs, as used to visualize soft tissues, can be useful in
identifying small flakes of bone.