Abstract Submission Form All abstracts must be submitted to the AOCR by September 15 th. All information included must be the original work of the author(s) and be in typed form. Incomplete or handwritten abstracts will not be considered. At least one (1) author of the work or a designated representative must be present at the AOCR Annual Convention. Exhibit Title: Carpal Dislocation vs. Instability: A Clarification of the Imaging Findings Primary Author and Affiliation: Nicholas Strle, PGY-4 Oklahoma State University Additional Contributors: Corey Matthews, PGY-3 Oklahoma State University Submission Category: Educational Subspecialty Area: MSK Trainees Only Training Program: Oklahoma State University Supervising Faculty: Donald von Borstel, DO Please state any related disclosures or conflicts of interest: N/A Learning Objectives (3-5): 1. Developing an approach to evaluating the wrist on initial plain film radiography 2. Review of basic wrist anatomy 3. Discussing and differentiating the most common imaging manifestations of carpal instability and dislocation I attest that the following required documentation is included with this form: Narrative Abstract (maximum of 500 words) Five (5) PowerPoint slides with representative content that will be included in the exhibit. o The PowerPoint slides must contain images, but no more than two (2) tables/charts and five (5) embedded images. Please submit your form, narrative, and PowerPoint slides to Mary Lentz at the AOCR by emailing mary@aocr.org.
Carpal dislocation vs. Instability: A Clarification of the Imaging Findings The learning objectives of this exhibit include: reviewing an approach to evaluating the wrist on plain film radiography, reviewing basic wrist anatomy, and discussing the most common imaging manifestations of carpal instability and carpal dislocation. The wrist demonstrates classic patterns of injury which can be confidently diagnosed on plain film radiography, therefore making it the initial imaging modality of choice. The first step toward accurate evaluation is to ensure proper wrist positioning. With proper positioning in the anteriorposterior (AP) projection, the carpal bones should be parallel with undisrupted arches, normal in shape (implying normal tilt and axis), and equally spaced. The shape of the lunate, capitate, and scaphoid require close attention, as they are the most common carpal bones to be pathologically misaligned. The lateral projection helps determine which carpal bones are aligned with the radius in dislocations and in which direction the lunate is tilted in cases of intercalated segment instability. Scapholunate advanced collapse (SLAC wrist) is degenerative joint disease centered at the radioscaphoid joint, with associated scapholunate ligament (SLL) tear and progressive interval widening and degenerative change of the lunocapitate joint. Scaphoid nonunion advanced collapse (SNAC wrist) is posttraumatic arthritis and carpal collapse after scaphoid nonunion fracture. Volar intercalated segment instability (VISI) is associated with lunotriquetral ligament injury where the lunate is volarly flexed with a capitolunate angle >30 degrees and scapholunate angle <30 degrees. Dorsal intercalated segment instability (DISI) is associated with scapholunate ligament injury where the lunate is dorsiflexed with a scaphlunate angle >60 degrees and capitolunate angle >30 degrees. The scaphoid often appears triangular in the AP projection. Lunate and perilunate dislocations are the most common dislocation involving the wrist and are easily differentiated from each other using the lateral radiograph. If the lunate is aligned with the radius and the capitate is displaced posteriorly, the diagnosis is a perilunate dislocation. If the capitate is aligned with the radius and the lunate is displaced anterior, the diagnosis is a lunate dislocation. Carpal instability is a significant source of chronic pain and disability. The wrist is a highly organized group of ligaments and bones which normally allow for stable transition of strength, dexterity, and fine motor control from the forearm to the hand; functions which are progressively limited as carpal instability worsens. Therefore, knowledge of these specific patterns can allow earlier identification and expedite subsequent treatment.
Carpal Dislocation vs. Instability: A Clarification of the Imaging Findings AOCR Education Exhibit Abstract 09/15/2017
Perilunate Dislocation Dorsal capitate dislocation (red arrow) Preservation of the radiolunate joint (blue arrow)
Lunate Dislocation Volar lunate dislocation (blue arrow) The capitate remains centered with radius (red arrow)
Dorsal Intercalated Segment Instability (DISI) Dorsally angulated lunate (blue arrow) Posterior capitate dislocation (red arrow) Capitolunate angle >30 48
Scapholunate Advanced Collapse (SLAC) Widened scapholunate interval (blue arrow) Proximal migration of the capitate (red arrow) Degenerative changes of the radioscaphoid joint (green arrow) at the radial styloid
Scaphoid Nonunion Advance Collapse (SNAC) Widened scapholunate interval (blue arrow) Nonunion scaphoid fracture with proximal osteonecrosis (red arrow) Degenerative changes of the radioscaphoid joint (green arrow)