12. Lunotriquetral Dissociation
• Occur with a fall on an
outstretched hand with
the wrist in extension and
radial deviation
• Atraumatic causes include
inflammatory arthritis
and ulnar abutment
Scapholunate Dissociation
• Trauma : injury results
from a fall onto an
outstretched, ulnar
deviated hand
• Atraumatic causes such as
infection and
inflammatory arthritis
From : Carpal Ligament Instability, NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.2020
13. Lunotriquetral Dissociation
• A cadaveric study observed
lunotriquetral ligament tears in
36% of the specimens
• It is also apparent that age-related
tears of the proximal membranous
component of the lunotriquetral
ligament are common findings
Scapholunate Dissociation
• Evidence of scapholunate ligament
injury was observed in 35% of
cadaveric wrists.
• 29% of the specimens with
scapholunate ligament injuries had
associated degenerative changes.
• 30% of intra-articular distal radius
fractures are associated with
scapholunate ligament complex
injuries.
From : Carpal Ligament Instability, NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.2020
14. From : Green’s operative hand surgery 7th edition,2017
Scapholunate
Dissociation
15.
16. Lunotriquetral Dissociation
• A history of falling on the wrist and
landing on the hypothenar area with
continued wrist pain
• Ulnar sided wrist pain and decreased
grip strength
Scapholunate Dissociation
• Persistent wrist pain following a fall
onto an outstretched hand
• Decreased grip strength
• Experience popping or clicking during
activities
• Exacerbated when the wrist is placed
into extension and radial deviation
• Wrist motion may be limited
secondary to pain
From : Carpal Ligament Instability, NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.2020
17. Lunotriquetral Dissociation
• Pain can be elicited by palpation
over the lunotriquetral joint
• Ulnar deviation with pronation
and axial compression of the
wrist can result in a painful snap
• The lunotriquetral ballottement
test
• Kleinman's shear test
Scapholunate Dissociation
• Tender to palpation dorsally
over the scapholunate joint
• The scaphoid shift test
• Watson shift test
From : Carpal Ligament Instability, NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.2020
20. Lunotriquetral Dissociation
• AP and lateral view radiographs
• Arthroscopy helpful in making
diagnosis, as radiographs may be
normal
Scapholunate Dissociation
• AP and lateral view radiographs
• Arthrography indications
• may be used as screening tool for
arthroscopy
• MRI indications
• often overused as a screening
modality for SLIL tears
• Arthroscopy indications
• considered the gold standard for
diagnosis
From : Carpal Ligament Instability, NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.2020
24. From : Green’s operative hand surgery 7th edition,2017 and orthobullet
25. Lunotriquetral Dissociation
• Ulnar impaction syndrome
• Triangular fibrocartilage complex tears
• Kienbock disease (lunate avascular
necrosis)
• Triquetral avulsion fracture
• Pisotriquetral arthrosis
• ECU tendon subluxation/ tenosynovitis
• DRUJ arthrosis
• CIND-VISI
Scapholunate Dissociation
• Scaphoid fracture
• Kienbock disease (avascular
necrosis of the lunate)
• Ganglion cyst
• Flexor carpi radialis tendinopathy
• Extensor carpi radialis
brevis/longus tendinopathy
• CIND-DISI
From : Carpal Ligament Instability, NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.2020
26. Stage I: partial ligament injury
immobilization
physical therapy with reeducation of wrist
proprioception
arthroscopic ligament debridement with or
without thermal shrinkage
percutaneous K-wire fixation of the scapholunate
joint
From : Carpal Ligament Instability, NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.2020
27. Stage III: complete ligament injury with static
scapholunate interval widening
>repairable ligament
open dorsal scapholunate ligament repair +
reduction of interval
>nonrepairable ligament
dorsal ligament reconstruction
dorsal scapholunate capsulodesis
From : Carpal Ligament Instability, NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.2020
28. Acute injury with failed conservative management[19]
arthroscopy and injury classification[64]
Grade I: ligament attenuation, no gap between lunate and
triquetrum - > ligament debridement
Grade II: ligament attenuation, <2 mm gap - > ligament
debridement + K-wire fixation
Grade III: ligament disruption, >2 mm gap - > ligament
debridement + K-wire fixation
Grade IV: complete ligament disruption, able to pass arthroscope
between lunate and triquetrum - > open ligament repair
From : Carpal Ligament Instability, NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.2020
29. From : Carpal Ligament Instability, NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.2020
30. From : Orthobullet : https://www.orthobullets.com/hand/6041/scapholunate-ligament-injury-and-disi
31. From : Green’s operative hand surgery 7th edition,2017
Wolfe, Scott W. MD; Garcia-Elias, Marc MD; Kitay, Alison MD Carpal Instability Nondissociative, Journal of the American
Academy of Orthopaedic Surgeons: September 2012 - Volume 20 - Issue 9 - p 575-585 doi: 10.5435/JAAOS-20-09-575
34. Wolfe, Scott W. MD; Garcia-Elias, Marc MD; Kitay, Alison MD Carpal Instability Nondissociative, Journal of the American
Academy of Orthopaedic Surgeons: September 2012 - Volume 20 - Issue 9 - p 575-585 doi: 10.5435/JAAOS-20-09-575
35. Wolfe, Scott W. MD; Garcia-Elias, Marc MD; Kitay, Alison MD Carpal Instability Nondissociative, Journal of the American
Academy of Orthopaedic Surgeons: September 2012 - Volume 20 - Issue 9 - p 575-585 doi: 10.5435/JAAOS-20-09-575
36. Wolfe, Scott W. MD; Garcia-Elias, Marc MD; Kitay, Alison MD Carpal Instability Nondissociative, Journal of the American
Academy of Orthopaedic Surgeons: September 2012 - Volume 20 - Issue 9 - p 575-585 doi: 10.5435/JAAOS-20-09-575
37. Wolfe, Scott W. MD; Garcia-Elias, Marc MD; Kitay, Alison MD Carpal Instability Nondissociative, Journal of the American
Academy of Orthopaedic Surgeons: September 2012 - Volume 20 - Issue 9 - p 575-585 doi: 10.5435/JAAOS-20-09-575
38. Wolfe, Scott W. MD; Garcia-Elias, Marc MD; Kitay, Alison MD Carpal Instability Nondissociative, Journal of the American
Academy of Orthopaedic Surgeons: September 2012 - Volume 20 - Issue 9 - p 575-585 doi: 10.5435/JAAOS-20-09-575
39. Wolfe, Scott W. MD; Garcia-Elias, Marc MD; Kitay, Alison MD Carpal Instability Nondissociative, Journal of the American
Academy of Orthopaedic Surgeons: September 2012 - Volume 20 - Issue 9 - p 575-585 doi: 10.5435/JAAOS-20-09-575
40. Wolfe, Scott W. MD; Garcia-Elias, Marc MD; Kitay, Alison MD Carpal Instability Nondissociative, Journal of the American
Academy of Orthopaedic Surgeons: September 2012 - Volume 20 - Issue 9 - p 575-585 doi: 10.5435/JAAOS-20-09-575
Editor's Notes
The proximal carpal row, truly an intercalated segment between the radius and distal carpal row, is inherently unstable. If not for the capsule, ligaments, and muscles, the three bones would collapse when compressed by the distal carpal row against the radius. The obliquely oriented scaphoid would rotate into flexion and pronation, while the wedge-shaped (thinner dorsally than palmarly) lunate and triquetrum would collapse into extension and supination
Until recently, muscles were considered to have a negative influence on carpal stability. Instability was assumed to be a ligament insufficiency problem made worse by muscle contraction. Now we know that the assumption is wrong: muscles play an important stabilizing role
Chronicity: Traditionally, ligament injuries have been classified depending on the time elapsed from injury to diagnosis into three categories: acute, subacute, and chronic
Severity: Any carpal instability can be analyzed according to the severity of the resulting subluxation. If carpal misalignment appears only under high stress in specific wrist positions, the case is less severe than if it were permanently present. Based on this idea, three groups of instabilities exist: occult (partial ligament tears with no misalignment under stress), dynamic (complete ruptures exhibiting carpal misalignment only under certain loading conditions), and static (complete ruptures with permanent alteration of carpal alignment).
Etiology: Although most instability problems are caused by trauma, certain diseases (e.g., inflammatory arthritis) may also be responsible for a similar constellation of radiographic findings. In traumatic cases, especially if diagnosed early, effective repair of the ruptured ligaments is possible. If ligament rupture results from rheumatoid arthritis, strong remaining ligament tissue is unlikely.
Location: It is important to investigate the location of the most important dysfunctions (e.g., subluxation or joint gapping), which may or may not coincide with the location
of the primary lesion.
Direction: When present, the direction of the carpal misalignment is an important factor to consider; several patterns have been recognized. (3) ulnar translocation, when a portion of, or the entire proximal row, is (or can be) displaced ulnarly beyond normal limits; (4) radial translocation, when the proximal row can be passively displaced radially beyond normal, usually in the context of a radially malunited distal radius fracture; (5) dorsal translocation, when the carpal condyle, often as a result of a dorsally malunited fracture of the radius, is (or can be) displaced in a dorsal direction
-carpal instability dissociative (CID), in which the predominant dysfunction (i.e., ligament rupture or insufficiency) occurs between bones of the same carpal row. Most CIDs occur between the scaphoid and lunate, and less often between the lunate and triquetrum. Dissociative instabilities between the bones of the distal carpal row are rare, usually the result of a violent dorsopalmar crushing mechanism
- also known as carpal instability nondissociative (CIND).This group includes radiocarpal, midcarpal, and combined radiocarpal–midcarpal instabilities. If the entire carpus is malaligned (translocated) with respect to the radius in any direction, this is radiocarpal instability. If the proximal carpal row as a unit collapses and becomes unstable, either in
flexion or e
-“carpal instability complex” (CIC), where there are features ofxtension, this is a combined radiocarpal–midcarpal instability, a condition that is also known as nondissociative instability of the proximal carpal row both CID and CIND types. Carpal dislocations, if treated inadequately, may generate complex (i.e., CIC) patterns of instability where the dysfunction affects both the radiocarpal and the proximal intercarpal joint.
Various classification schemes have been proposed to aid in the diagnosis and treatment of carpal instability.
Two of the most common malalignment patterns are volar intercalated segment instability (VISI) and the more common dorsal intercalated segment instability (DISI)
DISI, when the lunate is regarded as an intercalated segment and appears abnormally extended relative to the radius and capitate;
VISI, when the lunate appears abnormally flexed
SLD : A fall on the outstretched hand with the wrist in extension and ulnar inclination and associated with midcarpal supination may cause a wide spectrum of injuries, from minor SL sprains to complete perilunar dislocations.
LTD : Most isolated injuries to the LTq ligaments are secondary to a backward fall onto the outstretched hand, with the arm externally rotated, the forearm supinated, and the wrist extended and radially inclined. In such circumstances, the impact is concentrated on the hypothenar area, and particularly on the pisiform, which acts as a punch against the extended triquetrum
DISI
AP radiographs,SL gap > 3mm with clenched fist view (Terry Thomas sign) ,cortical ring sign (caused by scaphoid malalignment) ,humpback deformity with DISI associated with an unstable scaphoid fracture, scaphoid shortening. Lateral radiographs ,dorsal tilt of lunate leads to SL angle > 70° on neutral rotation lateral ,capitolunate angle > 20°
Arthrography : may demonstrate the presence of a tear but cannot determine the size of the tear, positive finding of a tear may indicate the need for wrist arthroscopy
MRI : requires careful inspection of the SLIL by a dedicated radiologist to confirm diagnosis, low sensitivity for tears
VISI
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
Increased SL joint space. The “Terry Thomas sign,” white arrow named by Frankel after the English film comedian’s dental diastema, is considered positive when the space between the scaphoid and lunate appears abnormally wide compared with the contralateral side The SL gap should be measured in the middle of the flat ulnar facet of the scaphoid.120 A unilateral gap greater than 5 mm is diagnostic of SL dissociation. If there is no history of a specific traumatic episode, and yet there is an obvious SL diastasis, one must consider either a constitutionally increased SL gap, usually bilateral, with or without hyperlax ligaments.
To rule out the presence of an occult asymptomatic SL ligament injury, a comparative radiographic examination is critical (Figure 13.22).
Scaphoid ring sign. Black arrow When the scaphoid has collapsed into flexion, it has a foreshortened appearance in the anteroposterior view. In such circumstances, the scaphoid tuberosity is shown in the PA projection in the form of a radiodense circle or ring over the distal two-thirds of the scaphoid
Increased SL angle. In the lateral view, if the scaphoid lies more perpendicular to the long axis of the radius and the lunate appears normally aligned or abnormally extended, SL dissociation should be suspected. In such circumstances, the SL angle is greater than the usual 45 to 60 degrees (Figure 13.23). This angle will progressively increase as the lunate extends to accommodate the loss of height of the radial column, causing a dorsal subluxation of the capitate.
Palmar V sign. In the lateral view of a normal wrist, a wide “C”-shaped line can be drawn by joining the palmar margins of the scaphoid and radius. When the scaphoid is abnormally flexed, the palmar outline of it intersects the palmar margin of the radial styloid at an acute angle, forming a sharper, “V”- shaped pattern
Lateral radiographs : right pic dorsal tilt of lunate leads to SL angle > 70° on neutral rotation lateral , capitolunate angle > 20°
In such cases, the lunate’s dorsal pole is superimposed on the distal part of the capitate, implying an abnormal flexion of the bone. It is also pathognomonic of this problem, the so-called “seagull sign”—the distal outlines of the lunate and triquetrum adopt the form of a flying seagull (Figure 13.40). A widened SL joint is paradoxically common in LTq dissociations
Disruption in the proximal Gilula line (PA view) due to proximal translation of the triquetrum and/or lunotriquetral overlap
Lunotriquetral interval narrowing/subchondral cyst formation (PA view) suggestive of chronic injury
In the lateral projection, aside from the VISI pattern of misalignment, it is sometimes possible to find a decreased LTq angle. According to Reagan et al,79 the average LTq angle is 14 degrees. Assessment of this angular measurement requires films of excellent quality and considerable practice taking them because the longitudinal axis of the triquetrum is difficult to identify. Yet, identifying the relative position of the triquetrum axis relative to the lunate axis may help
Lunotriquetral angle (lateral view) : normal -3 to 31 degrees, becomes more negative (average -16 degrees) with lunotriquetral dissociation
Lateral right pic : 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)
