Understanding the anatomy of the ligaments of the wrist Evaluation of the biomechanical patterns and severity of ligamentous injury resulting in dorsal and volar intercalated instability of the wrist Reviewing the spectrum of MRI findings in dorsal and volar intercalated instability of the wrist including potential sequelae

Dorsal intercalated segmental instability (DISI) can occur as a result of scapholunate ligament disruption and volar intercalated segmental instability (VISI) can occur as a result of disruption to the ulnar half of the volar arcuate ligament and the lunotriquetral ligament. Whilst the scapholunate and capitolunate angles can be evaluated on X-ray, bone contusion, chondral integrity, avascular necrosis, and intrinsic ligamentous injuries are more precisely evaluated on MRI.

ANATOMY The ligamentous anatomy of the carpus is complex with multiple intrinsic ligaments (Fig. 1). Perilunate instability is common secondary intrinsic ligamentous injury and can range in severity from mild sprain to severe disruption. Progressive instability can lead to advanced arthritis of the radiocarpal and midcarpal joints, known as the SLAC wrist (Scaphoid Lunate Advanced Collapse).1 Initial assessment of potential wrist instability injuries commences with physical examination and orthogonal plain x-ray views. The anteroposterior (AP) view is useful to assess Gilula’s lines and the scapholunate...

Ligamentous injuries of the wrist can cause carpal instability. MRI provides precise evaluation of the status of the wrist to help prevent the development of severe debilitating consequences.

1. Wolfe SW, Katz LD, Crisco JJ. Radiographic progression to dorsal intercalated segment instability. Orthopedics. 1997;19 (8): 691-5 2. Gilula LA. Dorsal intercalated segment instability (DISI) and scapho-trapezio-trapezoid (STT) osteoarthritis. J Hand Surg Br. 1995;20 (2): 264 3. Theumann NH, Etechami G, Duvoisin B et al. Association between extrinsic and intrinsic carpal ligament injuries at MR arthrography and carpal instability at radiography: initial observations. Radiology. 2006;238 (3): 950-7 4.Moritomo H. Radiographic clues for determining carpal instability and treatment protocol for scaphoid fractures. J Orthop Sci....

Rajat Chowdhury MA(Oxon), BMBCh, MRCS, FRCR, FBIR, PGCME Department of Radiology Nuffield Orthopaedic Centre Oxford University Hospitals NHS Foundation Trust Windmill Road Oxford UK E: [email protected]