Carpal instability

Abstract

This review addresses the pathoanatomical basics as well as the clinical and radiological presentation of instability patterns of the wrist. Carpal instability mostly follows an injury; however, other diseases, like CPPD arthropathy, can be associated. Instability occurs either if the carpus is unable to sustain physiologic loads ("dyskinetics") or suffers from abnormal motion of its bones during movement ("dyskinematics"). In the classification of carpal instability, dissociative subcategories (located within proximal carpal row) are differentiated from non-dissociative subcategories (present between the carpal rows) and combined patterns. It is essential to note that the unstable wrist initially does not cause relevant signs in standard radiograms, therefore being "occult" for the radiologic assessment. This paper emphasizes the high utility of kinematographic studies, contrast-enhanced magnetic resonance imaging (MRI) and MR arthrography for detecting these predynamic and dynamic instability stages. Later in the natural history of carpal instability, static malalignment of the wrist and osteoarthritis will develop, both being associated with significant morbidity and disability. To prevent individual and socio-economic implications, the hand surgeon or orthopedist, as well as the radiologist, is challenged for early and precise diagnosis.

Advanced imaging of the scapholunate ligamentous complex

“…In predynamic instability, plain radiographs, clenched fist films, and fluoroscopy are negative but the instability can be diagnosed clinically by arthroscopy or CTA and MRA images. Dynamic instability is visible on stress views (clenched fist) and at dynamic fluoroscopic assessment but not evident on standard radiographs, while static instability is present when a major primary stabilizer of the joint is fully ruptured and is evident on plain radiographs [13][14][15].…”

Effects of Scapholunate Ligament Injury and Surgical Repair on Wrist Cartilage T2 Relaxation Time

“…1 Rupture of the dorsal segment of the SLIL leads to scapholunate dissociation and rotatory subluxation of the scaphoid, as it is the primary stabilizing segment of the ligament. 13 SLAC, scapholunate advanced collapse, can result if the injury severity results in immediate gross dissociation or continued progression of dissociation. 7 , 14 Conservative treatment options, such as immobilization of the wrist and medication to reduce inflammation, may sometimes be utilized in chronic cases of scapholunate dissociation.…”

Evaluation of magnetic resonance imaging relaxation time in wrist cartilage with scapholunate ligament injury

“…As the severity of the injury increases, the injury is more likely to progress to SLAC wrist [4] . Rupture of the primary stabilizing segment of the SLIL, the dorsal segment, nearly always leads to scapholunate dissociation and rotatory subluxation of the scaphoid [5] .…”