Ulnar styloid impaction syndrome refers to wrist pain due to a long ulnar styloid process impacting upon the triquetral bone.
An unlar styloid >6mm in length is commonly regarded as being long. Impaction results in chondromalacia of the opposing articular surfaces, i.e. the proximal pole of the triquetral bone and ulnar styloid tip.
Treatment and prognosis
Surgical removal of the ulnar styloid process can effectively treat the condition.
A similar but distinct impaction syndrome due to non-union of the ulnar styloid (commonly following fracture) can also occur. This syndrome more commonly involves disruption of the TFCC complex.