Carpal Ligament Injuries, Pathomechanics, and Classification

Abstract

SYNOPSIS Carpal instability is a complex array of maladaptive and post-traumatic conditions that leads to the inability of the wrist to maintain anatomic relationships under normal loads. Many different classification schemes have evolved to explain the mechanistic evolution and pathophysiology of carpal instability, including two of the most common malalignment patterns of volar intercalated segment instability (VISI) and the more common dorsal intercalated segment instability (DISI). Recent classifications emphasize the relationships within and between the rows of carpal bones. Future research will likely unify the disparate paradigms used to describe wrist instability.

Current Management of Scaphoid Nonunion Based on the Biomechanical Study

“…The distal scaphoid pole is connected to the trapezium through the scaphotrapezial ligament, and the palmar radioscaphoid capitate and scaphoid capitate ligaments are secondary stabilizers between the scaphoid and distal row. 27,28 The scaphoid apex and proximal pole are linked with the lunate through the scapholunate interosseous ligament (SLIL). These ligamentous and osseous structures of the scaphoid provide a considerable degree of stability to carpal bones.…”

Defining DISI and VISI

“…DISI occurs when the lunate is dorsiflexed relative to the axis of the radius, usually following scapholunate dissociation, scaphoid nonunion or perilunate dissociation. This form of dissociative carpal instability results in the dorsal rotation of the triquetrum and lunate, while the scaphoid rotates unopposed in the volar direction (Lee and Elfar, 2015). Dissociative VISI occurs when both the lunate and scaphoid tilt in the volar direction and is secondary to a traumatic dissociation of the lunotriquetral ligament, accompanied by concomitant injuries to secondary ligaments.…”

Narrative Review of Ligamentous Wrist Injuries

“…8A). 67 It is important to note that isolated SLL injury does not generally lead to dorsal intercalated segment instability (DISI), which requires an additional injury of scaphotrapeziotrapezoid or dorsal intercarpal ligaments. 68 Depending on the severity and chronicity of the SLL injury, the patient can present with radial and dorsal wrist pain accompanied by wrist instability.…”

“…8A ). 67 It is important to note that isolated SLL injury does not generally lead to dorsal intercalated segment instability (DISI), which requires an additional injury of scaphotrapeziotrapezoid or dorsal intercarpal ligaments. 68 …”