What Is the Best Treatment for Acute Injuries of the Scapholunate Ligament?

Published on 11/03/2015 by admin

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Chapter 13 What Is the Best Treatment for Acute Injuries of the Scapholunate Ligament?

The scapholunate (SL) ligament is the fibrous structure that links the scaphoid and lunate bones of the wrist. It is composed of a thick and strong dorsal portion, a more pliable anterior portion, and finally an intervening membranous segment. It is the dorsal portion that plays the most important role for carpal stability.

Injury to the ligament usually occurs as a result of a fall on an outstretched hand resulting in wrist hyperextension, ulnar deviation, and midcarpal supination. Although the ligament can be injured in isolation, and the diagnosis missed, it can also be injured with fractures of the distal radius or scaphoid, which should raise clinical suspicion just as in perilunate dislocations.

Diagnosis of scapholunate dissociation (SLD) can usually be made on physical and radiologic examinations. Physical examination usually demonstrates localized tenderness and a positive scaphoid shift test. If there is a complete tear, radiologic findings may include an increased SL joint space and a “ring” sign where the scaphoid has an overlying ring or circle projection caused by its volar flexion deformity. Other tools that aid in the diagnosis are cineradiography, arthroscopy, and arthrography.

An acute injury to the SL ligament alters the linkage between the two bones resulting in a dissociative carpal instability, also known as an SLD. This can present clinically in a variety of stages depending on the severity of the original injury and the delay to clinical diagnosis. There is no consensus for the nomenclature for the various patterns of severity of SL injuries. Predynamic SLD is a partial injury where the ligament remains intact. Symptoms arise from the associated increase motion, but there is no instability. Dynamic SLD is a complete disruption of the ligament when it is still repairable. No cartilage damage exists, and secondary stabilizers are intact. No permanent malalignment and demonstration of the radiographic gap between the scaphoid exists, and the lunate may require special maneuvers. The third manifestation is static reducible SLD. Secondary stabilizers have become deficient. The radiographic appearance is quite apparent, but the deformity can still be reduced. Eventually, the insufficiency results in static fixed SLD where it cannot be reduced. Finally, there is progression to degenerative arthritis with cartilage loss resulting in scapholunate advanced collapse (SLAC) wrist.1 The rationale for treatment of acute SL injuries is to prevent the progression to a SLAC wrist.

EVIDENCE

Dynamic Injuries

Cast Immobilization.

Two case reports of successful management of an SLD associated with a distal radius fracture (DRF) managed by closed reduction and casting have been reported.11,12 However, Tang and coworkers,13 in a series of 20 patients with DRF and SLD, found at 1 year that 100% had clinical signs and positive radiographs. Eight patients underwent surgery at 1 year. Laulan and Bismuth,14 in a radiographic study of DRF in 29 patients with an SL injury treated by casting alone, found at 1 year that progressive carpal collapse occurred in 61% of patients.

K-Wire Fixation.

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