SLAC and SNAC Wrist: The Top Five Things That General Radiologists Need to Know.

Eliza Kompoliti,Apostolos H Karantanas,Mikaella Prodromou

doi:10.3390/tomography7040042

Abstract

Wrist osteoarthritis (OA) is a common painful condition that affects the patient’s quality of life by limiting the range of wrist motion and grip strength. Wrist OA often results from scapholunate advanced collapse (SLAC) or scaphoid nonunion advanced collapse (SNAC). Early diagnosis of SLAC and SNAC is crucial because it affects treatment planning. Thus, radiologists should be able to interpret the early imaging findings. This pictorial review discusses the pathophysiology and the clinical symptoms of SLAC and SNAC and presents the imaging findings with emphasis on the proper imaging algorithm. Finally, it focuses on the treatment according to the degenerative status of each of these patterns.

Highlights

The wrist is perhaps the most complex joint in the body
Wrist osteoarthritis (OA) occurs in about 95% as a periscaphoid problem, and it can result in severe functional disability [1]
Scapholunate advanced collapse (SLAC) and scaphoid non-union advanced collapse (SNAC) are the most common patterns (55%) of wrist OA, which follow a predictable sequence of degenerative changes [1,2,3,4]

Summary

Introduction

The wrist is perhaps the most complex joint in the body. Wrist osteoarthritis (OA) occurs in about 95% as a periscaphoid problem, and it can result in severe functional disability [1]. The instability induced by the SLL tear leads to loss of synchronized motion between the scaphoid and lunate bones and gradually results in dorsal intercalated segment instability (DISI), in which the lunate rotates dorsally around its joint with the radius. These changes have an impact on carpal orientation, on the position of the scaphoid, which shifts stress to radioscaphoid and capitolunate joints. Rotary subluxation of the scaphoid causes excessive loading to the radioscaphoid articulation, incongruence and contact at the dorsal and volar aspects of the radioscaphoid joint, resulting in a SLAC wrist [1]

Intra-articular fractures

Differential Diagnosis

Treatment

Findings

Conclusions