Summary Lunotriquetral Ligament Injuries are rare traumatic injuries to the wrist that can lead to volar intercalated segment instability (VISI) which is caused by a combination of injury to the lunotriquetral ligament and the dorsal radiocarpal ligament. Diagnosis can be made with lateral radiographs of the wrist with the presence of volar flexion of the lunate with a scapholunate angle < 30°. Treatment is usually surgical management which may range from closed reduction with pinning and ligament repair for acute instability, and lunotriquetral fusion for chronic instability. Epidemiology Incidence LT ligament injury is less common than SL ligament injury Etiology Mechanism LT ligament injury occurs with wrist hyperextension or extension and radial deviation scaphoid induces the lunate into further flexion while triquetrum extends VISI Deformity stands for volar intercalated segment instability a type of Carpal Instability Dissociative (CID) caused by advanced injury with injury to lunotriquetral ligament dorsal radiotriquetral ligament volar radiolunate ligament VISI may occasionally be seen in uninjured wrists in patients with ligamentous laxity this is in contrast to DISI deformity, which is always a pathologic condition Anatomy Lunotriquetral ligament C-shaped intrinsic ligament spanning the dorsal, proximal and palmar edges of the joint comprised of thick dorsal and volar regions and weak membranous portion dorsal LT ligament most important as a rotational constraint volar LT ligament thickest and strongest portion of the LT ligament transmits extension moment of the triquetrum Dorsal radiocarpal ligament (aka dorsal radiotriquetral ligament) extrinsic ligament that serves as a secondary restraint to VISI deformity, and loss of integrity allows lunate to flex more easily Volar long and short radiolunate ligaments extrinsic ligament that may be torn in advanced injury Presentation Symptoms ulnar sides pain that is worse with pronation and ulnar deviation (power grip) Physical exam LT shuck test (aka ballottement test) grasp the lunate between the thumb and index finger of one hand while applying alternative dorsal and palmar loads across the triquetrum with the thumb and index of the other hand positive test elicits pain, crepitus or increased laxity, suggesting LT interosseous injury Kleinman's shear test stabilize the radiolunate joint with the forearm in neutral rotation and with the contralateral hand load the triquetrum in the AP plane, producing shear across the LT joint positive test produces pain or a clunk Lunotriquetral compression test displacement of triquetrum ulnarly during radioulnar deviation which is associated with pain Imaging Radiographs lateral volar flexion of lunate leads to SL angle < 30° (normal is 47°) and VISI deformity capitolunate zigzag deformity seen with capitolunate angle increase to > 15° (lunate and capitate normally co-linear) AP unlike scapholunate dissociation, may not be widening of LT interval break in Gilula's arc may see proximal translation of triquetrum and/or LT overlap Arthroscopy helpful in making diagnosis, as radiographs may be normal Treatment Nonoperative observation indications may be attempted initially Operative CRPP (multiple K-wire fixation) with acute ligament repair +/- dorsal capsulodesis indications acute instability technique ligament reconstructions with bone-ligament-bone autograft and LT fusion have fallen out of favor in acute setting LT fusion indications chronic instability complications nonunion is a known complication arthroscopic debridement of LT ligament with ulnar shortening indications chronic instability secondary to ulnar positive variance long ulna chronically impacts the triquetrum, resulting in LT tear with instability often associated with degenerative tear of triangular fibrocartilage complex (TFCC)