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14
Percutaneous and Arthroscopic Management
of Scaphoid Nonunions
William B. Geissler
Department of Orthopedic Surgery and Rehabilitation, University of Mississippi Medical Center, Jackson,
Mississippi, U.S.A.
&
INTRODUCTION
Wrist arthroscopy has revolutionized the practice of orthopedics by providing the technical capability to examine and treat
intra-articular abnormalities of the wrist joint (1). Wrist arthroscopy allows for direct visualization and palpation of cartilage
surfaces,synovialtissue,and theinterosseous ligaments
under bright light and magnified conditions. The scaphoid is
wellvisualizedfromboththe radiocarpaland midcarpal
spaces. Fractures of the scaphoid are best visualized with the
arthroscope in the midcarpal space (Fig. 1). This allows for
arthroscopic assisted fixation of fracturesofthe scaphoid and
nonunions under directvisualization.
The scaphoid is the most frequently fractured carpal bone
and accounts for approximately 70% of all carpal fractures (2).
This injury typically occurs in young adult males between the
ages of 15 and 30 years (3). Scaphoid fracture is also acommon
athletic injury particularlyinfootballand basketball where
aggressive play frequently causes impact injuries to the wrist
(4). It is estimatedthatapproximately1out of 100college
football players will sustain afractureofthe scaphoid (4).
Acutenondisplaced fracturesofthe scaphoid have
traditionally been managedwithcastimmobilization(5,6).
Nondisplaced scaphoid fractures have been reported to heal
in 8to12weeks when immobilized in long- and short-arm
thumb spica casts (5,6). However,the reported rate of nonunion
for such fractures has been as high as 15% (5–7). The duration of
cast immobilization also varies dramatically according to the
fracturesite. Afracture of the scaphoid tubercle may be healed
within aperiod of six weeks, while afracture of the waist of the
scaphoid may take three months or more of immobilization.
Fractures of the proximal third of the scaphoid may take six
months or longer to heal with acast due to the distal vascularity
of the scaphoid (8).
Although cast immobilization may be successful in up to
90% of cases, it must be asked at what cost to the patient, who
may not be able to tolerate alengthy course of immobilization
(9). Prolonged immobilizationmay lead to muscleatrophy,
disuseosteopenia, possible jointcontracture,and financial
hardship (7). An athleteorworkermay be inactive for six
months or longer as the fracture unites. This may result in a
loss of athletic scholarship or employment.
Displaced fractureshaveareported nonunion rate of
approximately 50% (3). Factors that decrease the prognosis for
healing include displacement, the presence of associated carpal
instability,and delayed presentation greater than four to six
weeks (2). Traditionally, acutedisplaced fracturesofthe
scaphoid and scaphoid nonunions have been managed by
open reduction and internal fixation (2,3,10–17). This requires
significant soft tissue dissection. Complications have been
reported with the most common complication seen as hypertropic scar in one series (2,3). Other potential complications
include avascular necrosis, carpal instability,donor site pain
(bone graft), infection, screw protrusion, and reflex sympathetic
dystrophy (15,18). Jigs have been designed to assist in fracture
reduction, but are often difficult to apply requiring even further
extensive surgical dissection (19).
There are several factors that make healing of the scaphoid
difficult (20),ifnot prolonged.Scaphoidfractures uniteby
primary bone healing without external callus. The scaphoid is
almost entirely covered with articular cartilage. This limits the
amount of surface area for bone contact and consolidation. The
potential for synovial fluid to pass between the fracture fragments may also occur due to its intra-articular environment.
The scaphoid receives its primary blood supply from the
radial artery and branches of the anterior interosseous artery
(8). The most important vascular supplyentersalong the
dorsal ridge of the scaphoid. These vessels are responsible for
the majorityofperfusion of the proximal two-thirds of the
scaphoid. Thisblood supplyisquite tenuousand canbe
easily disrupted as the majority of scaphoid fractures (80%)
occur at the waist area or mid portion of the scaphoid (21). The
disruptionofblood supplyaffectsboneconsolidation,and
the timeuntilunion.Becauseofthe retrogradecirculation,
moreproximal fractures of the scaphoid requiregreatertime
until union. Approximately one-thirdoffractures of the waist of
thescaphoidand virtuallyall proximalone-fifth fractures
develop osteonecrosis (8).
&
INDICATIONS
Arthroscopic or percutaneousassisted fixation of scaphoid
fracturesoffers amiddle ground between the traditional treatment of cast immobilization for nondisplaced fractures and
open reduction for displaced fractures of the scaphoid (22–30).
The application of arthroscopic wrist techniques to scaphoid
fracture managementoffersmanyadvantages over conventional techniques. These techniques reduce surgical exposure
and minimize soft tissue dissection, which may cause potential
loss of vascularity to the fracture fragments. These techniques
avoidthe divisionofthe importantradioscaphoidcapitate
ligament andthe volarcapsule, whichrequires subsequent
repair andhealing(18).Inaddition, arthroscopic assisted
fixation avoids potential scar formation and allows for detection
and managementofany associatedintercarpal soft tissue
injuries, which may occur with afracture of the scaphoid.
Recent advances in arthroscopicassisted and percutaneous
fixation of scaphoidfractures allowthe majority of acute
fracturesofthe scaphoid to be managed by these modalities.
As surgeonsgainmoreexperiencewith these techniques,
severalauthors nowhavereported theirexperiencewith
arthroscopic and percutaneous management of nonunions of
the scaphoid (1,22–25,27,28,30–32). The purpose of this chapter
is to review the indications of surgical techniques for arthroscopicand percutaneous management of nonunionsofthe
scaphoid. These techniques are particularly applicable to the
young active population in which scaphoid fractures are most
commonly seen and in particular,this group is least likely to
tolerate prolonged periods of immobilization (33,34).
&
PREOPERATIVE EVALUATION
Posteroanterior (PA) and lateral radiographs are mandatory to
assess displacement, alignment, and angulation of ascaphoid
fracture.Inaddition, semi-pronated and semi-supinated views
are helpful to demonstrate the proximal and distal pole of the
scaphoidrespectively. Aposterior anterior radiograph with
the wrist in ulnar deviation extends the scaphoid for detection
of displacement. It is well recognizedthat anondisplaced
fracture may not be apparent on the initial radiographs for
several weeks. It is important to immobilize the patient who
presents with snuffbox tenderness until the pain resolves,or
until adiagnosis is confirmedradiographically.Frequently,
athletes simply choose to ignore the initial pain and discomfort
with an acute scaphoid fracture and appear after the season has
ended with adefined nonunion of the scaphoid (30,33).
Computer tomography (CT) parallel to the longitudinal
axis of the scaphoid is used to evaluate displacement, angulation, and healing when further information is required to assess
the scaphoid fracture. In this technique, the patient is placed
prone with the arms extended overhead, and with the wrist
radial deviated to obtain the longitudinal axis of the scaphoid.
Coronal slices are performed with supination of the forearm to a
neutral position. Percutaneous and arthroscopic reduction of
scaphoid fracture is indicated in patients without ahumpback
deformity.Ifahumpback deformity or rotation of the lunate is
demonstratedbyplain radiographs, or by CT scan, open
reduction and bone grafting is indicated.
Recently,Slade and Geissler published their radiographic
classificationofscaphoidnonunions (Table 1) (29).TypeI
fractures are the result of delayed presentation, i.e., 4to12
weeks from injury.Adelayed presentation is well known to be a
risk factor for nonunion of the scaphoid. In Ty pe II injuries, a
fibrous union is present. Aminimal fracture line is seen on the
plane radiographs. The lunate is neutral and there is no humpback deformity.InType III injuries, minimal sclerosis is seen
at the fracture site. The sclerosis is less than 1mminlength.
Again, the lunate is not rotated, and no humpback deformity is
seen on imaging studies. In Type IV injuries, cystic formation
has now occurred. The areaofcyst formation is between 1and
5mm. In Ty pe IV injuries, there is no humpback deformity of
the scaphoid, and no rotation of the lunate as seen on plane
radiographs. In Type Vinjuries, cystic changes are now greater
than 5mm. Ahumpback deformity may be seen either on plane
imaging studies or CT evaluation. The lunate has rotated into a
dorsal intercalated segment instability (DISI) position. Percutaneous and arthroscopic techniques for scaphoid nonunions are
not indicated in Type Vinjuries. In Type VI injuries, alongstanding nonunion of thescaphoidispresent.Secondary
degenerative changes, scaphoid nonunion advanced collapse
(SNAC), are seen with spurring along the radial border of the
scaphoid and peaking of the radial styloid. Again, percutaneous
andarthroscopic reduction techniques are notindicated in
Type VI injuries. Fixation of the scaphoid nonunion may still
be possible with removal of the bone spurs and radial styloidectomy.Inadvancedcases,salvage procedures such as
proximal carpectomy or four-corner fusion may be indicated.
&
SURGICAL TECHNIQUES
Various arthroscopicassisted and percutaneous techniques for
fractures of the scaphoid have been described in the literature
(22–28,30,32,36). These include the volar approach (popularized
by Haddad) and the dorsal approach (morerecently popularized by Slade) (25,27,28). In general, these techniques include
the use of asmall amount of wrist arthroscopy and asignificant
amountoffluoroscopy. As describedpreviously, fibrous
nonunionsofthe scaphoid andcysticscaphoidnonunions
without humpback deformity and rotation of the lunate are
amendable to these techniques. Significantly displaced fractures
with marked DISI rotation of the lunate particularly in achronic
situation are best managed by open reductionand internal
fixation (2,3,37).
&
Volar Percutaneous Approach
The percutaneous volar approach was popularized by Haddad
and Goddard(25). Utilizing this technique, the patient is placed
FIGURE 1 Fractures of the scaphoid are best seen from the midcarpal
space. Fractures of the waist of the scaphoid are best observed with the
arthroscope in the radial midcarpal portal. Fractures of the proximal pole
are ideally visualized with the arthroscope in the ulnar midcarpal portal as
seen here.
TABLE 1 ScaphoidNonunion Classification
Slade and Geissler
Type IDelayed presentation 4to12weeks
Type II Fibrous union, minimal fracture line
Type III Minimalsclerosis ! 1mm
Type IV Cystic formation, between 1and 5mm
Type VHumpback deformity, O 5mmcystic change
Type VI Wrist arthrosis
Source:From Ref. 35.
106&Geissler
supine and the thumb is suspended in aChinese finger trap
while the patient is undergeneral anesthetic or regional
anesthesia. Placementofthe thumbinsuspensioncauses
ulnardeviation of the wrist, which improves accesstothe
distal poleofthe scaphoid. Underfluoroscopiccontrol,a
longitudinal 0.5 cm incision is made at the most distal radial
aspect of the scaphoid. Blunt dissection is used to expose the
distal poleofthe scaphoid. Apercutaneous guide wire is
introduced into the scaphotrapezial joint and advanced proximally and dorsally across the fracture site. The position of the
guide wire is checked underfluoroscopyinthe anterior/
posterior,oblique, and lateral planes. The length of the guide
wirewithin the scaphoid is determined with adepth gauge and
adrill is inserted through asoft tissue protector to protect the
surrounding tissues. Aheadless cannulated screw is placed
over the guide wire after drilling. Asecond guide wire is helpful
to protect against rotation of the fracture fragments while the
screw is being inserted. Morerecently,self-drilling and selftapping headless cannulatedscrewshavebeen introduced
(Acumed, Beaverton, Oregon, U.S.A.). Skin closure requires
the use of asingle suture and the patient is encouraged to
begin active finger flexion exercises beforedischarge.
Haddad and Goddardreporttheir initial results in apilot
study of 15 patients with acute fracturesofthe scaphoid (25).
Unions were achieved in all patients in 57 days(range
38–71 days). The range of motion after the union was equal to
that of the contralateral limb and grip strength averaged 90% of
the contralateral limb at three months. Patients were able to
return to sedentary work within four days and manual work
within five weeks.
&
Dorsal Percutaneous Approach
Slade has described the dorsal percutaneous approachwith
fixation of stable, unstable acute fractures of the scaphoid and
selected nonunions (27–29). This technique has become popular
becauseofits simplicity and becauseitallows forfurther
arthroscopic evaluationand reductionofthe fracture.The
patient is placed supine on the table with the arm extended. It
is helpful to place several towels under the elbow to support the
forearmsothat it is parallel to the floor.The wrist is flexed and
pronated under fluoroscopy until the proximal and distal poles
of the scaphoid are aligned to form aperfect cylinder.Continuous fluoroscopy is useful as the wrist is flexed to obtain the true
ring sign. A14-guage needle with aneedle driver is then used as
adrill guide for a0.045 guide wire. Under fluoroscopy,the
needle is placed in the center of the ring and is parallel to the
beam of the fluoroscopy unit. The guide wire is then driven
across the central axis of the scaphoid from dorsal to volar until
thedistalend is in contactwith thescaphoidcortex. The
position of the guide wire is then evaluated under fluoroscopy
in the PA,oblique, and lateral planes while maintaining the
wrist in flexion. The wrist cannot be extended at this point;
otherwise the guide wire may be bent. Asecond guide wire is
then placed parallel to thefirstsothatits tiptouches the
proximal pole of the scaphoid cortex. The difference between
the lengths of the two guide wires is the resultinglength of
the scaphoid.
The tendency with thesepercutaneous techniques is to
insert ascrew that is too long. Ascrew that is too long may
potentially distract the fracture site, or can violate the joint
surface causing articular damage either to the scaphotrapezial
joint or radiocarpal joint. Therefore, it is important to subtract at
least 4mmfrom the measurement between the guide wires,
which provides the ideal length of the screw.Inthis way,the
screw may be placed fully buried in the bone to avoid damage
to the articular surface. In fractures that involve the proximal
thirdofthe scaphoid, morethan 4mmfrom the measurement
between the guide wires may be subtracted because it is not
essential to have the screw fill the entire length of the scaphoid.
The primary guide wire is then advanced volarly through
the trapezium along the radial side of the thumb metacarpal
and exits the skin after the screw length has been selected. The
guide wire is advanced volarly until its proximal end is flushed
with the proximal pole of the scaphoid. Now the wrist may be
extended without damage to the guide wire.
The wrist is then suspended in atraction tower and the
wrist can be evaluated arthroscopically.Fractures of the waist of
the scaphoid are best seen with the arthroscope in the radial
midcarpal portal. Fractures of the proximal pole of the scaphoid
are best seen with the arthroscope in the ulnar midcarpal portal.
The reduction of the scaphoid nonunion may be viewed directly
arthroscopically.Ifthe reduction is not satisfactory,the guide
wire may be advanced volarly across the fracture site but still
within thedistal pole of thescaphoid. Kirschnerwireor
joysticks may be placed in the dorsum of the proximal and
distal ends of the scaphoid fracture fragments. These joysticks
are then used to further reduce the fracture anatomically as
viewed directly arthroscopically with the arthroscope in the
midcarpal portal. Once the reduction is felt satisfactory,the
guide wireisthen advanced back proximally from volar to
dorsal into the proximal pole fragment of the scaphoid.
The wrist is then flexed, and the guide wire is advanced
back dorsally so that it protrudes from the skin. Aportion of the
guide wire is left protruding from the volar aspect of the hand as
well, so that the guide wire breaksorbends and can be easily
removed from either the volar or dorsal aspect of the hand. A
small incision is then made over the dorsum of the guide wire
and blunt dissection is carried down to the level of the joint
capsule. The guidepin maybeevaluatedsothatitisnot
impaling any of the dorsal extensor tendons to the hand or
sensory nerve branches. With the wrist in flexion, the scaphoid is
then reamed through asoft tissue protector.Asecondary guide
wire helps prevent rotation of the fracture fragments during
reaming of thescaphoidand screw insertion. Aheadless
cannulated screw is then inserted over the guide wire to the
depth previously reamed. It is important not to advance the
screw to the far cortex unless this has been reamed because this
may cause distraction of the fracture fragments. The position of
the screw is then checkedunder fluoroscopy to confirm its
centrallocation within thescaphoidand theguide wires
are removed.
It is important to re-evaluate the position of the screw and
the proximal pole of the scaphoid arthroscopically following
insertion. Under fluoroscopy,itmay appear that the screw is
well within the scaphoid. However,itpotentially may still be
protruding and arthroscopic evaluation is extremely helpful to
insure that thescrew is within thescaphoid. If thescrew
protrudesproximally it canpotentiallyinjurethe articular
cartilage of the scaphoid facet of the distal radius. The wrist is
suspended again in the traction tower and the arthroscope is
placed in the 3–4 portal to assess the position of the screw within
the scaphoid. Following confirmation of the screw placement,
the small dorsal incision may be closed with asingle nylon stitch.
&
Dorsal Percutaneous Approach with Arthroscopic
Confirmation of Starting Point (Geissler)
Most recently,Geissler described his arthroscopic technique for
reduction of acute scaphoid fractures and scaphoid nonunions
with cystic changes (Fig. 2) (38). In this technique, the wrist is
initially suspendedinanARC (Hillsboro,Oregon, U.S.A.)
Percutaneous and Arthroscopic ManagementofScaphoid Nonunions&107
traction tower (Fig. 3). The arthroscope is initially placed in the
3–4 portal to evaluate any associated soft tissue lesions, which
mayoccur with ascaphoidfracture. Upon evaluationand
treatment of any associated soft tissue injuries, the arthroscope
is then transferredtothe 6-R portal (Figs. 4–6). The wrist is
flexed to approximately 308 in the traction tower.A14guage
needle is then inserted through the 3–4 portal and the scapho-
lunate interosseous ligament (SLIO ligament) is palpated at the
junction of the scaphoid. The junction of the SLIO ligament
insertion onto the dorsal, middle thirdofthe scaphoid is the
ideal insertion point for ascrew.The 14-guage needle is then
advanced and impaled into the scaphoid right at the junction of
the SLIO ligament onto the dorsal middle thirdofthe scaphoid
(Figs. 7and 8).
FIGURE 2 Posteroanterior radiograph of acystic scaphoid nonunion in
a22-year-old male.
FIGURE 3 The wrist is suspendedinthe ARC traction tower. The
suspension bar, offtothe side, does not block fluoroscopic visualization
of the wrist.
FIGURE 4 The arthroscope is placed in the 6-R portal, and aprobe is
utilized to identify the junction of the scapholunate interosseous ligament
to the scaphoid.
FIGURE 5 Arthroscopic view of the scapholunate interval as seen with
the arthroscope in the 6-R portal.
108
&
Geissler
The traction tower is then flexed, and the starting point
of the needle is evaluated under fluoroscopy (Fig. 9). Utilizing
his technique, the starting point is always right at the most
proximal pole of the scaphoid. The needle is then simply aimed
towardthe thumb and aguide wireisthen placed through the
needle down the central axis of the scaphoid to abut the distal
pole (Figs. 10–12).The positionofthe guidewireisthen
evaluated on the PA,oblique, and lateral planes under fluoroscopy (Fig. 13). This is done by rotating the forearm in the
traction tower,asthe fluoroscopy beam is not hinderedbythe
tower.Asecond guide wire is then placed against the proximal
pole of the scaphoid, and the difference in length is measured
between the guide wirestogive the length of the scaphoid
screw.Just as Slade has recommended,ascrew at least 4mm
shorter is utilized. Reduction of the scaphoid is then evaluated
with the arthroscope in the radial and possibly ulnar midcarpal
portal. If the reduction is satisfactory,the guide wire is then
advancedout the volaraspect of the wrist. Theadvantage
of this technique is the wrist is not hyperflexed as compared
to the percutaneous dorsal technique. Thus the fracture site
is not potentially flexed to produce ahumpback deformity.
In addition,the insertionpoint of theguide wire into the
scaphoid is precisely identified arthroscopically.
The scaphoid is then reamed over the guide wire with a
secondary Kirschnerwiretoprotectrotation in astandard
fashion (Fig. 14). Aheadless cannulated screw is then inserted
FIGURE 6 Arthroscopic view with the arthroscope in the 6-R portal and
aprobe beingplacedinthe 3–4portalprobing thejunctionofthe
scapholunate interosseousligamenttothe scaphoid.
FIGURE 7 A14-guage needle impales the middle third of the scaphoid
at thejunction of thescaphol unateinterosseousligamentonthe
scaphoid after it has been identified with the probe.
FIGURE 8 The proximal pole of the scaphoid is then impaled with a
14-guage needle at thejunctionofthe scapholunate interosseous
ligamentonthe scaphoid.
FIGURE 9 Fluoroscopic view confirming the ideal starting point for the
guide wire on the proximal pole of the scaphoid. The ideal st arting
point has now been confirmed by direct visualization arthroscopically
and fluoroscopically.
Percutaneous and Arthroscopic ManagementofScaphoid Nonunions
&
109
over theguide wire.The position of thescrew within the
scaphoid is checked under fluoroscopy in the PA,lateral, and
oblique planes while the wrist is still in the tower.Following
screw placement, the position of the screw within the scaphoid is
evaluated arthroscopically with the arthroscope in the 3–4 portal
to insure that it is not protruding and potentially causing damage
to the articular cartilage of the scaphoid facet of the radius.
&
OUTCOMES
Geissler and Slade described utilizing the dorsal percutaneous
fixation technique in 15 patients with stable fibrous nonunions
of the scaphoid (39). In their series, there were12horizontal
oblique fractures, one transverse fracture, and two proximal
pole fractures. Fourteen of the fifteen patients weremale and
relatively young. The average presentation time to the clinic
following injurywas eightmonths. Allpatientsunderwent
percutaneous dorsalfixationwith aheadless cannulated
screw.Nopatients had an accessory bone grafting procedure.
In their series,all fractureshealedatanaverage of three
months. Of the 15 patients, eight patients underwent CT evaluation, which further documented healing. The patients had
excellent rangeofmotionasaresultofminimal surgical
dissection. Utilizing the modified Mayo wrist scale, 12 of the
FIGURE 10 The ARC traction tower is then flexed down and the needle
is aimed toward the thumb.
FIGURE 11 Aguide wire is then placed with aheadless cannulated
screw down the long axis of the scaphoid and confirmed fluoroscopically.
FIGURE 12 The wrist may then be supinated in the ARC traction tower
and the position of the guide wire confirmed on the oblique and lateral
planes.
FIGURE 13 Fluoroscopic image in the oblique view confirmingthe ideal
location of the guide pin down the mid axis of the scaphoid.
110
&
Geissler
15 patients had excellent results. Dorsal percutaneous fixation
wasrecommended for thosepatientswithastablefibrous
nonunion without anysigns of humpback deformityand
without extensive sclerosis at the fracture site. Utilizing the
scaphoid nonunion classification scheme as proposed by Slade
and Geissler,patientswith Type II and Ty pe IIIscaphoid
nonunions were included in the study.
Most recently,Geissler described his technique of arthroscopicreductionofcysticscaphoidnonunions without
humpback deformity(38). Utilizingthe scaphoid nonunion
classificationschemeofSlade andGeissler, hisserieswas
composed of Type IV scaphoid nonunions. In Geissler’s technique, aguide wire is again placed arthroscopically as
previously described with the arthroscope in the 6-R portal
and the guide wire is placed through a14-guage needle to the
3–4 portal.The scaphoidisthen reamed with asofttissue
protector once confirmation of ideal placement of the guide
wireisnoted under fluoroscopy in the PA ,oblique, and lateral
planes. The guide wire is then advanced out volarly but still
beingmaintainedinthe distal poleofthe scaphoid.The
nonunion site maybepercutaneouslycurettedunder
fluoroscopythrough thedrill hole in theproximal poleof
the scaphoid.
One cubic centimeter of demineralized bone matrix (DBM;
Accell, IsoTis, Irvine, California) is then injected percutaneously
into the nonunion site of the scaphoid. This may be done several
different ways. Acustomized putty pusher was designed to
inject the putty directly into the nonunion site. If this is not
available, aJamshidi needle is usually readily available in most
operating rooms (Fig. 15). The demineralized bone matrix is
injected into the bone biopsy needle, which is then inserted into
the drill hole of the scaphoid, and the plunger is used to push
the putty directly into the nonunion site (Figs. 16–18). Lastly,the
FIGURE 14 Thescaphoidisthenreamed through asofttissue
protector over the guide wire.
FIGURE 15 Demineralized bone matrix will be injected down the mid
axis of the scaphoid after it has been reamed through aJamshidineedle
with the plunger.
FIGURE 16 The demineralized bone matrix putty is initially loaded into a
syringe, which then is used to inject the putty down the Jamshidineedle.
FIGURE 17 The Jamshidi needle is then placed over the guide wire
down the mid axis of the scaphoid into the nonunion site.
Percutaneous and Arthroscopic ManagementofScaphoid Nonunions
&
111
demineralized bone matrix may be injected into astandard
syringe. A14-guage needle or angio cath may then be placed
into the drill hole of the scaphoid, and the putty again injected
into the nonunion site. Once the demineralized bone matrix
putty has been injected into the scaphoid nonunion, the guide
wire is then advanced back dorsally and exited the skin. A
headless cannulated screw is then placed over the guide wire
andinserted into thescaphoid(Figs.19–23). Arthroscopic
evaluation of the wrist is then performed in both the midcarpal
and radiocarpal spaces to evaluate reduction of the scaphoid
nonunion, and to evaluate for any extravasation of demineralized bone matrix putty into the joint.
Geissler reported hisresults in 15 patients with cystic
scaphoid nonunions (38). Fourteen of the 15 patients healed
their cystic scaphoid nonunions utilizing his technique. Arthroscopicevaluationofthe wristbothinthe radiocarpaland
midcarpal spaces showed no extravasation of the demineralized bone matrix putty into the joint.
DBM is allograft bone that has been demineralized. The
bone morphogenetic proteins (BMPs) are preserved following
thedemineralizationprocess.The entire cascade of bone
morphogenetic proteins evokes conversion of the mesenchymal
FIGURE 18 The guide wire is then advanced distally out of the nonunion
site while still maintainingits position in the distal pole of the scaphoid.
The putty is then injected into the nonunion site of the scaphoid.
FIGURE 19 The guide wire is then advanced proximally through the
Jamshidi needle after the demineralized bone matrix putty has been
injected. An Acutrak headless cannulatedscrew is then placed over the
guide wire and advanced into the scaphoid.
FIGURE 20 The position of the headless cannulated screw may then
be checked while maintainingtraction in the ARC traction tower.
FIGURE 21 The position of the headlesscannulated screw is then
viewed fluoroscopically.
112
&
Geissler
cell to the preosteoblast and eventually to the osteoblast, which
is involved in bone formation. DBM is available in two forms,
dry or injectable. DBM is mixed with acarrier for the injectable
form.Carriersinclude hyaluronic acid, collagen,glycerol,
gelatin and the actual derivatives of DBM itself. Commercial
providers may mix the DBM and carriers in different combinations and proportions. Products with higher DBM content
may be considered moreeffective because of the active ingredient in BMP is contained within the DBM itself, and not within
thecarrier.Carrierssuchashyaluronic acid,collagen, and
glycerolare inert and do not induce bone formation.
One way to understand the various DBM putties is to
imagine them as achocolate chip cookie. The cookie itself is
inert and acts as acarrier for the sweet chocolate chips (BMPs).
The morechocolate chips (BMP) in the cookie, the sweeter or
better the cookie is perceived. Analogously,DBM putties with a
higher BMP content may be considered moreeffective. Second
generation DBM putties have ahigher content of BMPs. It is
important that the surgeon understands the differences between
the various commercialproducts available. In this way,the
surgeon may pick aDBM putty with ahigh content of BMPs.
In Geissler’s study,aproduct that was 100% osteoinductive was
utilized in that the carrier itself was DBM and has been shown
to induce bone formation. This may be especially valuable in
fractureswhere only asmall amount of DBM putty may be
injected, such as the scaphoid (Figs. 24–28).
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SUMMARY
Fractures of the scaphoid are acommon carpal injury.This
fracture generally occurs in young males, and is acommon
athletic injury.Most fractures of the scaphoid will heal with
cast immobilization. However,approximately 10% to 15% of
scaphoid fractures will proceed to nonunion.
Arthroscopicand percutaneousfixationofscaphoid
nonunions is not indicated in all cases. However,itisparticularlyusefulinTypeII, Ty pe III, and Ty pe IV scaphoid
nonunions as described by Slade and Geissler (29). In patients
with afibrousnonunion, potentially stabilizationalone is
all that is necessary to promote healing (39). In cystic changes
and in patients with cystic scaphoid nonunions, Geissler has
shown good success with arthroscopic stabilization and percutaneous injection of DBM putty into the nonunion site (38).
FIGURE 22 Once ideal placementofthe screw has been confirmed
fluoroscopically, the screwdriver is removed. Notice how the cystic area
of the scaphoid has filled with the demineralizedbone matrix putty.
FIGURE 23 Oblique view of the scaphoid confirmingideal location of
the headless cannulated screw.
Percutaneous and Arthroscopic ManagementofScaphoid Nonunions
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