The dorsal portion of the ligament is thick 2 to 3 mm with transversely oriented bundles of collagen.2-4 This portion appears to provide the bulk of the ligament’s resistance to diasta-s
Trang 1Injuries to the scapholunate region
are among the most common acute
and chronic wrist ligament injuries
treated by orthopaedic surgeons
Diagnosis and treatment guidelines
have changed as a result of the
con-tinued clinical experience with this
condition.1 To diagnose this injury
accurately requires a thorough
un-derstanding of the pertinent normal
anatomy and kinematics, patterns of
injury, and the relative utility of the
various imaging methods The
ad-vent of new treatment techniques,
as well as current research into the
reconstruction of this complex
soft-tissue lesion, makes defining the
optimal treatment for an individual
patient a constantly developing
pro-cess Scapholunate dissociation
may be either static or dynamic In
the case of the former, standard
wrist radiographs are always abnor-mal In the latter instance, standard radiographs are normal, and the diagnosis is made with a combina-tion of pertinent findings on clinical examination and stress radiographs
or, in many cases, with diagnostic arthroscopy
Anatomy
Stability of the scapholunate com-plex depends on both extrinsic cap-sular ligaments and the scapholu-nate interosseous ligament (SLIL)
The SLIL is a C-shaped structure connecting the dorsal, proximal, and volar surfaces of the scaphoid and lunate (Fig 1) The cross-sectional anatomy of this ligament varies con-siderably from dorsal to volar The
dorsal portion of the ligament is thick (2 to 3 mm) with transversely oriented bundles of collagen.2-4 This portion appears to provide the bulk
of the ligament’s resistance to diasta-sis between the proximal pole of the scaphoid and lunate.3 Between the most proximal portions of the scaphoid and lunate, the SLIL is thin and fibrocartilaginous and blends into the attachment of the ligament
of Testut (palmar radioscapholunate ligament) This proximal, fibrocarti-laginous portion of the SLIL is most easily visualized during wrist ar-throscopy Palmar to the radio-scapholunate ligament attachment lies the palmar portion of the SLIL, which is thin (1 mm) and obliquely oriented (Fig 1)
Other interosseous ligaments that stabilize the scaphoid include the scaphocapitate and scaphotrapezium-trapezoid ligaments3(Fig 2) Their attachments near the distal pole of the scaphoid provide additional
re-Dr Walsh is Assistant Professor, Section of Hand Surgery, Department of Orthopaedic Surgery, University of South Carolina School
of Medicine, Columbia, SC Dr Berger is Professor of Orthopedic Surgery, Mayo Clinic, Rochester, Minn Dr Cooney is Professor of Orthopedic Surgery, Mayo Clinic.
Reprint requests: Dr Cooney, Mayo Clinic,
200 First Street SW, Rochester, MN 55905 Copyright 2002 by the American Academy of Orthopaedic Surgeons.
Abstract
Injuries to the scapholunate complex present the surgeon with both diagnostic
and treatment dilemmas The anatomic features, biomechanical properties,
radiographic appearance, and surgical treatment algorithms of this small but
structurally and kinematically important joint continue to be refined A
thor-ough history and physical examination, combined with a radiographic
evalua-tion that can include plain radiographs, tomography, moevalua-tion studies,
arthrogra-phy, or MRI, usually will define the nature of the ligament injury Arthroscopy
is considered the gold standard for complete evaluation of scapholunate
interosseous ligament injury and often is performed as a first step before repair
or reconstruction Procedures such as carpal fusions or capsulodesis can limit
excessive scaphoid motion, promote wrist stability, and potentially prevent
arthritis, but advances continue to be made in direct scapholunate interosseous
ligament reconstruction Challenges for the future involve improving
noninva-sive evaluation, defining the degree of extrinsic ligament injury, and improving
direct repair and reconstruction.
J Am Acad Orthop Surg 2002;10:32-42 Interosseous Ligament Injuries
John J Walsh, MD, Richard A Berger, MD, PhD, and William P Cooney, MD
Trang 2sistance to scaphoid flexion.
The palmar capsular ligaments,
which provide support for the
scaph-oid and lunate, include the
radio-scaphocapitate ligament and long
and short radiolunate ligaments1
(Fig 2) The radioscaphocapitate
ligament attachment to the palmar
radial cortex of the scaphoid makes
it analogous to a radial collateral
ligament, while the long and short
radiolunate ligaments stabilize the
lunate in rotation Dorsal capsular
ligaments include the dorsal
radio-carpal and dorsal interradio-carpal
liga-ments, which share insertions on
the triquetrum (Fig 3) The
orien-tation of these fibers provides the
basis for the preferred incision used
with a dorsal capsulotomy, which
splits the dorsal radiotriquetral
liga-ment proximally and the dorsal
intercarpal ligament distally (Fig 4)
Kinematics
An understanding of the salient
points of carpal kinematics is
neces-sary to highlight differences
be-tween normal and injured wrists
Several theories to explain carpal
kinematics have been proposed
These include, among others, the row, column, and oval ring theories
In the row theory,5 the proximal carpal row is interlinked by the interosseous ligaments and moves independently of the distal carpal row In flexion-extension, the
scaphoid and lunate rotate together but the scaphoid moves through a greater arc.2,3 The scaphoid also pronates and ulnarly deviates dur-ing wrist flexion, which partially explains the oblique asymmetry of the scapholunate interval that develops after injury to the SLIL This scapholunate interval (or gap) also changes with radial-ulnar devi-ation of the wrist The scaphoid flexes during radial deviation and extends with ulnar deviation, which maintains the continuity between the rows during motion in the fron-tal plane However, with an SLIL injury, the scaphoid will remain flexed while the lunate extends, espe-cially with radial-to-ulnar deviation, and the diastasis or gap between the scaphoid and lunate often will enlarge
The column theory6-9posits a lat-eral column (scaphoid, trapezoid, trapezium), a central column (capi-tate and lunate), and an ulnar col-umn (hamate and triquetrum) It is proposed that each column
pro-Dorsal Thick dorsal ligamentous
portion of SLIL
Proximal (fibrocartilage)
region of SLIL
Thin palmar
ligamentous
portion of SLIL
Radioscapholunate
ligament
Neurovascular bundle Palmar
Long
radiolunate
ligament
Short radiolunate ligament Lunate
Figure 1 The scapholunate interosseous ligament (SLIL) viewed from the proximal/radial
side with the scaphoid removed (Adapted with permission from Cooney WP, Linscheid
RL, Dobyns JH [eds]: The Wrist: Diagnosis and Operative Treatment, vol 1 St Louis, Mo:
Mosby-Year Book, 1998 By permission of Mayo Foundation.)
Figure 2 Palmar view demonstrating interosseous wrist ligaments and palmar radiocarpal
ligaments (in bold type) The key ligaments are the radioscaphocapitate, long and short radiolunate, and ulnar carpal ligaments (ulnolunate, ulnotriquetral and ulnocapitate liga-ments) C = capitate; H = hamate; I = first metacarpal; L = lunate; P = pisiform; R = radius;
S = scaphoid; Td = trapezoid; Tm = trapezium; U = ulna; V = fifth metacarpal (By permis-sion of Mayo Foundation.)
Ulnocapitate
P
L
Ulnotriquetral ligament Ulnolunate ligament
Capitotrapezoid ligament
Scaphotrapezium trapezoid ligament
Scaphocapitate ligament
Radioscaphocapitate ligament
Long radiolunate ligament
Short radiolunate ligament
Palmar radioulnar
Trang 3vides different types of wrist
sta-bility The lateral column is mobile;
the central column provides
flexion-extension and the medial column,
carpal rotation Craigen and Stanley6
have demonstrated that individual
carpal bone motion varies with
wrist motion and that women are
more likely to have a wrist that
de-monstrates column-type kinematics
In the oval ring theory,10articular
contact and ligament control are provided by the radial and ulnar connections in the carpus between the proximal and distal carpal rows
Mobility and carpal stability are controlled by linkages between the scaphoid and trapezium radially and the lunate and triquetrum ul-narly Instability results when a break occurs in a linkage Both the row theory and oval ring theory ap-pear to be more in agreement with commonly recognized concepts of carpal instability and scapholunate dissociation
The effect of sequential section-ing and repair of the SLIL on wrist kinematics has been evaluated in the laboratory The dorsal region of the ligament was found to be the most important structure defining the alignment and kinematics of the scapholunate complex.4 The palmar region appears to have a limited ef-fect on scapholunate kinematics
With an SLIL tear, the scaphoid will flex and rotate away from the lunate The scaphoid moves in conti-nuity with the distal carpal row through its attachments to the trape-zium, trapezoid, and capitate, while the lunate and triquetrum move together as a proximal carpal row unit With the scaphoid and lunate
no longer linked, the lunate and tri-quetrum extend This combination
of scaphoid flexion and lunate exten-sion produces a dorsal intercalated segment instability (DISI deformity), which is characteristic of scapholu-nate disassociation Carpal kinemat-ics are altered as a result
Individual differences in carpal kinematics and carpal ligament laxity may be factors in explaining the var-ied clinical presentations and treat-ment results of carpal instability
Material Properties
Cadaveric studies have been used to evaluate the stabilizing function of the SLIL11 as well as the material properties of the three separate liga-ment regions.12 The dorsal region of the ligament provides the greatest constraint to translation between the scaphoid and lunate in the dorsal-palmar direction, while both the dor-sal and palmar regions constrain the extremes of rotation between the scaphoid and lunate The dorsal region is the strongest, failing at approximately 250 N of stress, fol-lowed by the palmar region (120 N) and the proximal region (60 N).12
The breaking strengths (i.e., strengths
to failure) of the radiocarpal liga-ments also have been determined (100 N for the radial collateral liga-ment, 150 N for the radioscaphocapi-tate, 110 N for the long radiolunate, and 40 N for the radioscapholunate ligament [ligament of Testut]) It appears that injury must occur to both interosseous and capsular liga-ments for rotational instability of the scaphoid to be present This is there-fore the rationale for incorporating a capsulodesis or tenodesis procedure into the SLIL repair to restore stability
Mechanism of Injury
The exact mechanisms of injury that produce scapholunate dissociation
Dorsal
intercarpal
ligament
I
V C T S
radiocarpal ligament
Figure 3 Dorsal radiocarpal and
inter-carpal ligaments from the distal scaphoid.
Note the origin of the dorsal intercarpal
ligament from the distal scaphoid (S) and
the combined insertion of both the
radio-carpal and interradio-carpal ligaments on the
tri-quetrum (T) LT = Lister’s tubercle (By
permission of Mayo Foundation.)
Figure 4 Dorsal fiber-splitting capsulotomy The incision splits between the dorsal
radiotriquetral ligament proximally and the dorsal intercarpal ligament distally (A) and
has a radial-based flap (B) (By permission of Mayo Foundation.)
Joint
capsule
Capitate
Hamate Triquetrum
Lunate Scaphoid
Dorsal intercarpal ligament Dorsal radiocarpal ligament Dorsal radioulnar ligament
Trang 4have not been fully elucidated
May-field et al13 and Johnson14 suggest
that a sudden impact load applied
to the base of the hypothenar region
of the hand with the wrist in
exten-sion, ulnar deviation, and
supina-tion produces a scapholunate
disso-ciation.15 In theory, with the wrist in
this position, the capitate is driven
between the scaphoid and lunate,
the scaphoid is forced away from
the lunate radially and dorsally, and
the lunate is displaced ulnarly and
palmarly
The degree of initial injury
re-quired to produce scapholunate
diastasis and pathologic lunate
rotation is still poorly understood
Berger et al16 demonstrated few
kinematic changes after SLIL
sec-tioning, whereas Short et al17
showed scaphoid flexion and
pro-nation as well as lunate extension
after SLIL section, with the degree
of diastasis between the scaphoid
and lunate dependent on the
direc-tion of wrist modirec-tion Capsular
lig-ament support is undoubtedly an
important factor influencing the
findings The occurrence of the
ini-tial injury or an injury followed by
repetitive stress may cause a slow
attenuation of capsular ligaments,
allowing further instability Wolfe
et al18 reported a case of
hyperex-tension wrist injury with normal
scapholunate angle and interval on
initial radiographs and slow
pro-gression to frank carpal instability
over the next 11 weeks The
associ-ation of interosseous ligament
inju-ries with distal radius fractures also
has been described.19,20
Diagnosis
History and Physical
Examination
A history of a fall or sudden load
on the wrist should alert the
clini-cian to consider in particular a
radial-side wrist injury, such as scaphoid
fracture or scapholunate instability
Some diagnoses, such as scapho-trapezial arthritis, radioscaphoid arthritis, de Quervain’s tenosynovi-tis, dorsal wrist impaction syn-drome, dorsal ganglion cyst, and perilunate wrist instability, can be excluded after a careful clinical his-tory and examination of the wrist.1,8
Some patients with wrist injuries may not be able to recall one specific episode of trauma, as is frequently the case with scaphoid fractures that initially present with nonunion
This may be the result of the rela-tively trivial nature of the original injury, which is ignored by the pa-tient because of the demands of ath-letic competition or work Wrist in-stability also may be associated with synovitis, which can contribute to gradual ligament attrition Repeti-tive stress alone, however, is rela-tively unlikely to produce a scapho-lunate dissociation
The history reported by the pa-tient with scapholunate dissociation usually includes weakness and pain with loading activities (such as push-ups).21 Physical findings usu-ally include swelling in the radial snuffbox or dorsoradial tenderness over the scapholunate interval just distal to Lister’s tubercle, discomfort
at the extremes of wrist extension and especially radial deviation, and
a positive ballottement test (dorsal-volar stress manipulation of the scapholunate interval) Subluxation
of the proximal pole of the scaphoid associated with a clunk during dy-namic wrist loading (the Watson maneuver) frequently is present on dynamic testing.13 The Watson test
is particularly important in the diag-nosis of dynamic scapholunate in-stabilities It is performed by plac-ing the wrist in ulnar deviation and supporting the distal end of the scaphoid with the examiner’s thumb palmarly at the scaphoid tubercle
The wrist is then radially deviated
A sensation or palpation of a catch
or clunk is felt as the scaphoid sub-luxates over the dorsal rim of the
distal radius There also may be progressive loss of grip strength when the patient is asked to do a repetitive gripping maneuver
Imaging
Because many methods of radio-graphic imaging are available, an organized approach is best for determining the sequence of differ-ent imaging techniques as well as the role of arthroscopy in evaluating the painful, unstable wrist The ini-tial study is complete radiographic assessment with six views of the wrist (posteroanterior, lateral, radial deviation, ulnar deviation, flexion, and extension) In a patient with scapholunate dissociation, standard posteroanterior radiographs (neu-tral radioulnar deviation) show an increased scapholunate gap (≥3 mm compared with the opposite wrist),
a cortical ring sign of the flexed scaphoid (the ring appearing <7
mm from the proximal pole), and extension of the lunate with prominence of the volar pole, which overlaps the proximal capitate, characteristic of dorsal rotation of the trapezoid-shaped lunate The scaphoid is vertical due to the rota-tory subluxation (Fig 5, top) Lateral radiographs best show scaphoid flexion and lunate extension relative
to the radius (Fig 5, bottom) The longitudinal axes of the scaphoid and lunate are used to determine the scapholunate angle, which is 95 degrees (normal, 45 ± 15 degrees) The lunocapitate angle measures 30 degrees (normal, 0 ± 10 degrees) The scapholunate angle also can be measured by assessing the degree of palmar scaphoid flexion with re-spect to the volar cortical surface of the distal radius.22 An associated dorsal translation of the capitate on the lunate also can be measured Flexion and extension lateral views will show motion occurring primar-ily at the lunocapitate joint and an uncoupling of the normally syn-chronous scapholunate motion
Trang 5Ra-dioulnar deviation may show a
clos-ing scapholunate gap, with radial
deviation and opening of the gap
with ulnar deviation The
clenched-fist posteroanterior views may
accen-tuate these changes, especially the
scapholunate diastasis
Among other findings that may
be present in long-term scapholunate
dissociation are isolated
scapho-trapeziotrapezoid arthritis,
calcifi-cation of articular cartilage from
calcium pyrophosphate deposition,
and advancing stages of arthrosis,
which typically follow a pattern
termed scapholunate advanced
col-lapse.1,21,23,24
In patients with subacute and
dy-namic scapholunate dissociation, the
standard radiographic views of the wrist usually do not demonstrate any abnormalities To make a diag-nosis of both subacute (usually <3 months from injury) and dynamic scapholunate instability, additional imaging information is usually re-quired The next imaging modality should be midcarpal and radiocar-pal arthrography Wrist arthrogra-phy may demonstrate an SLIL tear, although arthrography cannot help
in assessing the size of the tear In addition, asymptomatic perforations have been found in the contralateral wrist, so interpretation must be cor-related with clinical findings Con-versely, comparative studies have shown only a 60% sensitivity of arthrography compared with ar-throscopy.25 Nonetheless, arthrog-raphy remains a valuable screening tool to demonstrate SLIL tears, determine the potential diagnosis in combination with other studies, and serve as a prelude to arthroscopy or arthrotomy of the wrist
MRI is of questionable value in as-sessing most patients with a scapho-lunate dissociation.26 Currently MRI of the wrist is often overused
in the evaluation of suspected in-terosseous ligament injuries MRI
of the scapholunate complex
re-quires a dedicated radiologist, exact positioning, and careful inter-pretation of results (Fig 6) The varieties in structure of the dorsal, proximal, and volar portions of the SLIL (particularly where it joins the vascular mesocapsule of the ra-dioscapholunate ligament) make interpretation of intraligamentous signal change difficult.26,29 The portion of the ligament most fre-quently shown to be torn is the most proximal fibrocartilaginous portion, which contributes far less
to wrist stability than does the dor-sal portion.3,16 Indeed, one study showed the sensitivity of MRI of the SLIL to be less than 40% com-pared with arthroscopy, leading the authors to conclude that “mag-netic resonance imaging is unhelp-ful in the investigation of suspected carpal instability.”30
Arthroscopy currently is consid-ered to be the imaging method of choice by most surgeons.25,30-32 Ra-diocarpal and midcarpal arthros-copy with triangulation probing greatly assist in the diagnosis and staging of scapholunate dissociation (Fig 7) Staging the severity of an SLIL tear can be performed best by radiocarpal and midcarpal arthros-copy.33,34
Figure 5 Posteroanterior (top) and lateral
(bottom) radiographs show increased
scapho-lunate gap (arrowhead), volar flexion of the
scaphoid (ring sign), and lunate dorsiflexion.
(By permission of Mayo Foundation.)
Figure 6 A, Coronal T2-weighted fast spin echo MRI (2,137/100) of flap tear of the SLIL.
The wrist is in neutral position The arrow indicates the free edge of the torn ligament on the scaphoid (Reproduced with permission 27) B, Coronal T2-weighted MRI of SLIL tear
(arrow) and separation of the scaphoid and lunate (Reproduced with permission 28 )
30°
ring sign C
L
Trang 6Geissler et al33 have proposed a
method of quantifying the degree of
interosseous ligament injury by
probe placement into the
scapholu-nate interval from the radiocarpal
and midcarpal joint on wrist
ar-throscopy In grade I injuries,
atten-uation of the interosseous ligament is
seen from the radiocarpal space with
no midcarpal step-off Patients with
suspected injuries are often
immobi-lized In grade II injuries,
attenua-tion is seen from the radiocarpal joint
(Fig 7, A and B), and an
incongru-ency between the scaphoid and
lunate is seen from the midcarpal
joint (Fig 7, C) With Kirschner wire
(K-wire) joysticks placed
percuta-neously dorsally into the scaphoid
and lunate, the midcarpal step-off is
reduced and the scapholunate
inter-val is pinned for 6 to 8 weeks In
grade III and IV injuries, a complete
separation between the scaphoid and
lunate is seen from both the
radio-carpal and midradio-carpal spaces In the
grade III injury, a small 1-mm probe
passes between the carpal bones, and
in the grade IV injury, a 2.7-mm
arthroscope passes between the
carpal bones Grade III represents an
increased separation between the
scaphoid and lunate with normal
scapholunate angles, whereas grade
IV represents an established
scapho-lunate dissociation with a
scapholu-nate gap ≥3 mm on the
anteroposte-rior view and a lateral scapholunate angle >70 degrees The grade III car-pal instability should be treated by open repair The grade IV should be treated by open repair combined with a capsulodesis
Arthroscopy of the wrist is now recognized as an essential compo-nent of evaluation of scapholunate instability Both the radiocarpal and the midcarpal space must be evaluated arthroscopically when scapholunate instability is
suspect-ed Wrist arthroscopy is not com-plete if the midcarpal space is not examined in the assessment of scapholunate instability.33,34
Treatment Determination of Surgical Treatment
Surgical treatment of scapholu-nate injuries is determined based
on time elapsed from injury, the amount of carpal instability, and the presence of any secondary changes in the carpus (Table 1) Treatment decisions can be sep-arated into three categories based
on the chronicity of the instability: acute, subacute, or chronic For patients with acute scapholunate instability, who may initially pre-sent with symptoms compatible with a wrist sprain, splint or cast immobilization was often recom-mended With the diagnostic tests
of wrist arthrography and wrist arthroscopy, earlier diagnosis of actual ligament tears should lead to more specific treatment initially, such as percutaneous pin fixation
or open SLIL repair The degree of tear of the SLIL as assessed by wrist arthroscopy assists in deter-mining the treatment Partial tears
of the SLIL discovered by arthros-copy (grades I and II) potentially can progress, and the
recommend-ed treatment by some authors is arthroscopic pin fixation for 6 to 8
Figure 7 Wrist arthroscopy A, Radiocarpal joint with intact volar carpal ligaments
B, Probe on scapholunate ligament tear (right wrist) C, Midcarpal arthroscopy with
probe within scapholunate joint showing minimal scapholunate separation S = scaphoid;
R = radius; L = lunate, C = capitate (By permission of Mayo Foundation.)
Table 1 Surgical Treatment of Scapholunate Injuries
Radiographic
pinning, capsulodesis
and capsulodesis, capsulodesis alone, tenodesis alone, intercarpal fusion
* Dynamic deformity = present on stress (motion radiographs); positive clinical stress testing, positive arthroscopy, but negative arthrogram and normal static radiographs
† STT = scaphotrapezial-trapezoid; SC = scaphocapitate
S
L S
R
S
L C
Trang 7weeks to promote ligament healing
or to affect a scapholunate joint
chondrodesis.35,36
Whipple22described arthroscopic
reduction and pinning of the
scapho-lunate interval with multiple (4 to
5) pins He reported an 85%
inci-dence of symptom relief with 2- to
7-year follow-up in patients whose
initial presentation was <3 months
from injury and who had a <3-mm
side-to-side gap difference Other
authors refer to this same
patho-logic entity as dynamic
scapholu-nate dissociation and recommend
capsulodesis to support the
weak-ened SLIL.37
Acute, complete tears of the
SLIL, which can occur with
perilu-nate dislocations of the wrist and
commonly are associated with the
finding on plain radiographs of
scapholunate diastasis, are best
treated by open reduction and
repair of the SLIL Neutralization of
rotational forces during healing
usu-ally is augmented by pin
stabiliza-tion.38-40
Subacute scapholunate
dissocia-tion presents weeks or months after
the initial ligament tear and often
with limited clinical findings The
Watson stress test is positive but
static imaging studies can be
nega-tive Dynamic wrist imaging will
usually show a scapholunate
diasta-sis Arthrography often is negative,
but wrist arthroscopy is positive,
particularly at the midcarpal
arthroscopy This condition also is
referred to as dynamic scapholunate
dissociation Treatment of subacute
or dynamic scapholunate
dissocia-tion is by capsulodesis or tenodesis
when conservative treatment fails
SLIL tears recognized late (>12
weeks from initial injury) present as
established or chronic carpal
insta-bility They have the classic
radio-graphic findings of scapholunate
dissociation with a scapholunate
diastasis and increased
scapho-lunate angle.38,39 Wrist
arthrogra-phy and arthroscopy usually are not
needed to determine the diagnosis
If sufficient ligament remains for repair and the dissociation is cor-rectable at the time of surgery, then direct ligament repair combined with dorsal capsulodesis, as de-scribed by Lavernia et al,38Dobyns and Linscheid,39and Cooney et al,40
is recommended Otherwise, stabi-lization procedures such as capsu-lodesis,41,42 tenodesis,43,44 or inter-carpal fusions are recommended
Repair Techniques
Scapholunate Ligament Repair
A number of techniques exist for the treatment of scapholunate dis-sociation Primary repair of the SLIL is recommended for acute injury, for subacute injury with established ligament dissociation (positive arthrogram and Geissler
stage III or IV arthroscopic instabil-ity), and, combined with capsulo-desis or tenocapsulo-desis, for chronic in-stability
In the direct repair technique (Fig 8), the scapholunate interval is assessed from a dorsal approach The dorsal capsular incision is planned to construct a capsulodesis
to assist the repair The SLIL is almost always attached to the lunate The proximal pole of the scaphoid is prepared by freshening the proximal edge with a curette or burr and by placing drill holes for sutures that will be placed through the ligament Horizontal mattress sutures of 2-0 or 3-0 Ticron (Davis
& Geck, Wayne, NJ) are placed in the SLIL and passed through drill holes that exit at the waist of the scaphoid (Fig 8, C and D) K-wires (0.0625 inch) are placed dorsally
Figure 8 Schematic of direct SLIL repair A and B, Joysticks plus retrograde K-wire drilling of the proximal scaphoid C, Ligament repair through the waist of the scaphoid with emphasis on dorsal SLIL repair D, Completed SLIL repair (Adapted with
permis-sion from Cooney WP, Linscheid RL, Dobyns JH [eds]: The Wrist: Diagnosis and Operative
Treatment, vol 1 St Louis, Mo: Mosby-Year Book, 1998 By permission of Mayo
Foundation.)
Scaphoid
Trang 8to act as joysticks to reduce the
scapholunate interval Once
re-duced, the scapholunate interval is
pinned by a minimum of two
0.035-or 0.045-inch K-wires The d0.035-orsal
joystick K-wires are removed and
the sutures securely tightened
Capsulodesis
Capsulodesis is strongly
recom-mended for late (chronic) instability
to augment the ligament repair
Capsulodesis alone also is
recom-mended for subacute (dynamic)
scapholunate instability The Blatt
repair41utilizes a distally based
dor-sal flap of capsule that is left
at-tached to the radial styloid (Fig 9)
A notch for flap attachment is made
in the distal scaphoid This capsular
flap is attached distally to the
scaph-oid, either through a drill hole
(dor-sal to palmar with a tie-over button)
or with a suture anchor The
capsu-lar flap (ligament) is inserted after
the scaphoid is derotated and held
with a K-wire The second option is
the dorsal intercarpal ligament
cap-sulodesis1,42 (Fig 10) The dorsal
intercarpal ligament is elevated at
the time of wrist exposure so that it
is lifted off the triquetrum ulnarly
but left attached to the distal carpal
row and specifically to the distal
scaphoid radially This ligament
strip (with its distal carpal
attach-ments) then is sutured to the dorsal
radius The scaphoid is rotated out
of flexion to neutral position
(45-degree scapholunate angle) and
held with the capsulodesis Both
the Blatt capsulodesis and dorsal
intercarpal capsulodesis work by
holding the scaphoid extended and
supporting the SLIL repair
Tenodesis of the Wrist
Tenodesis of the wrist is an
al-ternative surgical approach to the
problem of the unstable scaphoid
For tenodesis, a tendon is harvested
through either a dorsal or palmar
surgical approach, freed throughout
its length, then transferred through
the distal scaphoid and attached to the dorsal radius (or lunate) to serve as a method of stabilizing the unstable scaphoid Popular tech-niques described include that of Linscheid,1Brunelli and Brunelli,43
and Van Den Abbeele et al.44 In the technique of Linscheid, half of the extensor carpi radialis tendon is released proximally and left at-tached distally to the base of the second metacarpal The detached end is passed dorsally to palmarly
through a drill hole in the scaphoid tuberosity (Fig 11, A) The tendon exiting from the palmar hole is pulled through the drill hole to con-nect to a small incision over the scaphoid tuberosity (Fig 11, B) The tendon end is then passed around the waist of the scaphoid (volar back to dorsal), then ulnarly
to the lunotriquetral ligament and dorsal joint capsule (Fig 11, C) Part of the tendon can be used to reinforce the dorsal aspect of the
Figure 10 Schematic of intercarpal ligament capsulodesis using the proximal half of the
dorsal intercarpal ligament (DIC) to link the distal scaphoid to the distal radius A, The
scaphoid is rotated into extension by the capsulodesis of the proximal half of the DIC
(arrow), which is attached to the dorsal rim of the distal radius DRC = dorsal radiocarpal
ligament B, Lateral view of the DIC capsulodesis showing derotation (arrow) of the
scaphoid (By permission of Mayo Foundation.)
R S
Td Td
S
L T DIC
DRC
Figure 9 Blatt dorsal capsulodesis A, Distally based capsular flap is attached to the scaphoid to create derotation (arrows) B, Tightening of the capsulodesis applies pressure
to the distal scaphoid (arrows) (Adapted with permission from Blatt G: Dorsal
capsulode-sis for rotary subluxation of the scaphoid, in Gelberman RH (ed): The Wrist, New York,
NY: Raven Press, 1994, pp 147-167.)
Pullout suture Dorsal flap Notch
Trang 9SLIL repair1before its final
attach-ment distally on the capitate to a
suture or through drill holes (Fig
11, D)
In the procedure of Brunelli43
(Fig 12), half of the flexor carpi
radialis tendon is harvested from a
palmar approach The distal end is
left attached to the trapezoid and
base of the second metacarpal The
freed proximal end is passed volarly
to dorsally through a drill hole in
the distal scaphoid The scaphoid is
realigned and the tendon pulled
taut The tendon end is then
insert-ed dorsally into the distal radius
This tenodesis serves to tighten the
palmar scaphotrapezial-trapezoid
ligaments distally and to derotate
the scaphoid proximally, correcting
carpal alignment
An alternative insertion of the tendon dorsally onto the lunate rather than to the distal radius was described by Van Den Abbeele et
al44(Fig 12, B) Both tenodesis pro-cedures can be used alone, as can the dorsal capsulodesis procedures, when the SLIL cannot be directly repaired
Bone-Ligament-Bone Techniques
Attempts to achieve a recon-struction that more closely repro-duces the dorsal support of the SLIL have generated research into using bone-ligament-bone compos-ite grafts Tarsometatarsal joint autograft, SLIL allograft, and bone-retinaculum-bone autograft har-vested from the dorsal radius have all been attempted45-48(Fig 13)
These procedures currently are investigational, and there have been no long-term assessments of the outcome of bone-ligament-bone reconstructive procedures for scapholunate dissociation The capitohamate ligament composite serves as an excellent source for graft to replace the SLIL With a dorsal approach, the dorsal capito-hamate ligament is harvested as a bone-ligament-bone graft and trans-ferred to the scapholunate interval
Intercarpal Fusion
Shortcomings in soft-tissue tech-niques have caused some to advo-cate scaphoid stabilization by scaphotrapezial-trapezoidal (STT) fusion21,49 or scaphocapitate (SC) fusion.23 Although it provides sta-bilization of the scaphoid and re-stores scaphoid alignment with the distal radius, intercarpal fusion can change carpal kinematics substan-tially, potentially leading to later degenerative arthritis.50
Advocates recommend inter-carpal fusion when there is immedi-ate need for a stable wrist, reason-able motion, and heavy manual
Figure 11 Ligament augmentation of Linscheid.1A, Strip of detached extensor carpi radialis
longus tendon, with K-wire joysticks inserted into the scaphoid and lunate B, The tendon is
pulled through the drill hole C, The tendon is then passed across the dorsal part of the
scapholunate interval to the triquetrum and through the ulnar wrist capsule D, The tendon
can be used to reinforce the dorsal portion of the SLIL (By permission of Mayo Foundation.)
Figure 12 Brunelli technique of tenode-sis 43 A, Half of the flexor carpi radialis
(FCR) tendon is passed through the distal
pole of the scaphoid B, Dorsal view
show-ing the FCR slshow-ing attached to either the dis-tal radius (the original Brunelli technique)
or to the dorsal lunate (the modified tech-nique of Van Den Abbeele et al 44 ) (Adapted with permission 44 )
T
S
R FCR
Trang 10labor Watson et al49have
demon-strated satisfactory fusion rates,
with retention of 70% of normal
motion and 80% of grip strength
Early outcome appears to be
satis-factory Radial styloidectomy has
been recommended to improve
mo-tion and to reduce the incidence of
arthritis secondary to radial-scaphoid
impingement.51 The combination of
an STT or SC fusion, which realigns the proximal scaphoid to the scaph-oid fossa of the distal radius, and
a limited radial styloid excision, which makes the radioscaphoid joint more congruent, seems to offer satisfactory long-term results in properly selected patients.52
Salvage procedures for late scapholunate dissociation are based
on the pathophysiology and pro-gression of degenerative arthritis
In general, a proximal row carpec-tomy (provided no lunocapitate ar-thritis exists) or scaphoid excision and midcarpal fusion provide rea-sonable options of treatment.52-54
These procedures can preserve an arc of motion that is about 50% of normal while relieving pain sec-ondary to degenerative changes
Summary
The future treatment of SLIL dissoci-ation likely will center around improved diagnostic assessment of the combined capsular and interos-seous ligament injuries Diagnosis and treatment algorithms likely will incorporate minimally invasive radio-graphic assessment, wrist arthros-copy, and surgical procedures that focus on each component and reduce the postoperative period of wrist im-mobilization, resulting in improved wrist motion, strength, and stability
Autograft
Figure 13 (A) Preparation of the bed for placement of a bone-ligament-bone graft into the
dorsal scapholunate interval (B) K-wire fixation Dotted lines indicate the area of
resec-tion of the bone-retinaculum-bone graft site (Adapted with permission 48 )
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