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SURGICAL TECHNIQUE
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3.5 mm ASIF Compression Plate
The patient is kept in the supine position and the affected arm is
placed on aradiolucent arm board. Atourniquet is placed as
high as possible on the arm. This technique, as first described by
Ruch et al.(31),requires three incisions. Thefirstincision,
measuring approximately 4cminlength, is madeoverthe
midshaftofthe long fingermetacarpal. The metacarpalis
clearedofsoft tissues while the extensor tendon is retracted
and protected. Asecond incision, again measuring approximately 4cm, is made over the dorsum of the distal aspect of the
radius. Under fluoroscopic guidance, this incision should be
placed at least 4cmproximal to the proximal most aspect of the
fracture.Blunt dissection should be carried down to the distal
radius and care must be taken to avoid injury to the superficial
branchofthe radial nerve. Afterpreparing thefirsttwo
incisions, palpate Lister’s tubercle and make a2-cm incision
directly over the bony landmark. Fully release the extensor
pollicis longus (EPL) and retract it radially.Mobilizing the EPL
facilitatesbothplate insertionand theapplicationofbone
graftfor fillingvoids at thesubchondral surface of the
distal radius.
Plate selection should be based on the size of the patient
and the proximal extent of the comminution of the distal radius
fracture. Lay a12-, 14-, 16-, or 20-hole 3.5-mm Association for
theStudy of Internal Fixation(ASIF)compression plate
(Synthes, Paoli, Pennsylvania, U.S.A.) on the overlying skin
of the wrist and use the C-arm to ensure that aminimum of
three cortical screws can be placed proximal to the fracture.
Starting at thedistalincisiondirectthe plate toward the
proximal incisions over the distal radius. Ensurethat the plate
is applied beneath the extensor tendons but extra-articular to
the carpus by visualizing the plate through the incision over
Lister’s tubercle. Once passed to the proximal most incision,
recheck, through the middle incision, that impingement has
not occurred between the plate and the EPL or digital extensors.
At this time, the plate should be secureddistally with ascrew
placed in the midline of the shaft of the metacarpal. Midline
placement of screw ensures that the hand will not rotate in
relation to the forearm when the plate is eventually secured to
the radius.
Next, the radial length must be restored. Using manual
traction under fluoroscopic guidance, apply aserrated clamp
through the proximal incision to securethe plate to the radius
once an appropriate length has been obtained. Prior to securing
the proximal plate with screws,full rotation of the forearm
should be confirmed. Furthermore, full passive motion of all the
digits should be possible. If full flexion is not possible, then plate
impingement on the extensor tendons is likely and extrinsic
extensor tightness will occur if this is not resolved. Once the
surgeon is assured of full motion, the plate can be secured
proximally with screws. Theremainingholes overlyingthe
metacarpal can also be filled at this time.
With theplate in itsfinalpositionand radial length
restored, the surgeon can now direct attention to reducing the
articular surface and restoring joint congruity.Any metaphyseal
defects can be bone grafted through the incision made over
Lister’s tubercle. The bone graft will help elevate and buttress
anyarticular fragmentsoverlyingthe defects. Due to an
increasedriskofinfection,bonegraftingshouldnot be
performedinagrossly contaminatedfracture or in injuries
with soft tissue defects that preclude primary wound closure.
Further buttressing of the lunate fossa can be provided with a
3.5-mm screw inserted through the mid-portion of the plate just
under the subchondral bone of the lunate facet. Some fragments
that require reduction may be too small for screw purchase.
In this instance, 0.45 or 0.62 in. K-wires should be implemented
to reduce and stabilize these fragments. This is often the case
with the radial styloid and fragments from the intermediate
column. Once satisfied with the placement of the plate and joint
reduction, the surgeon needs to address the distal radioulnar
joint (DRUJ). DRUJ stability should be checked in pronation,
neutral, and supination, and compared with the contralateral
side. If instability of the DRUJ is evident, then any large fractures
of the ulnar styloid should be repaired and the forearm splinted
in supination with some type of long-arm splint.
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2.4 mm Mandibular Reconstruction Plate or Distal
Radius Bridge Plate
Another technique, as described by Hanel et al. (32), utilizes
either a22-hole 2.4-mm mandibular reconstructionplate
(Synthes) or a2.4-mmdistal radiusbridge(DRB) plate
(Synthes) (Fig. 5). In this method, the plate is applied under
the second dorsal compartment and secured to the index finger
metacarpal distally.
Similar to the prior technique, the patient is kept in the
supine positionand theaffected extremity is centered on
FIGURE 4 Atrue lateral of the wrist with the pisiform overlying the distal
pole of the scaphoid ( arrow).
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Lauder et al.
aradiolucent arm board. To urniquets can be used but are not
necessary and are not currently implemented by the senior
author (D.P.H.). Sterile mesh finger traps are applied to the
index and middle fingers after the completion of prepping and
draping. Using aropeand pulley system, 4.5 kg of longitudinal
traction should be appliedand an initial closed reduction
performed (Fig. 6). After the initial setup is complete, aplate
should be selected. Both plate systems allow for the placement
of locked screws effectively making them fixed-angle devices.
The mandibular plate has only threaded screw holes, while the
DRB plate provides combination holes with both locked and
non-locked options.The mandibular reconstruction plateis
titanium, has scalloped edges, squared-off ends, and comes in
a12- or 20-hole size. The DRB plate is stainless steel and has
tapered edges. It comes in one size, which is equivalent to the
length of a20-hole mandibular reconstruction plate.
Superimpose the chosen plate over the dorsal skin of the
wrist in aline from the distal metaphyseal flare of the index
metacarpal to thediaphysisofthe radius(Fig. 7).Using
fluoroscopic guidance,markout incisionsthatare centered
over the proximal and distal most four screw holes (Fig. 8).
The plate should be of sufficient length to allow aminimum of
three screws both distally and proximally.Depending on one’s
preference, the arm can be exsanguinated and the tourniquet
inflated at this time or the skin can be infiltrated with 0.25%
bupivicaine with epinephrine for hemostasis. The distal incision
is made over the base of the second metacarpal and extends
distally over the shaft for approximately 5cm. The extensor
tendons to the index finger should be retracted ulnarly and the
insertions of the extensor carpi radialis longus (ECRL) and
extensor carpi radialis brevis (ECRB) should be identified at
their insertion points on the bases of the second and third
metacarpals, respectively.Asecond incision is made proximal
to the outcropper muscles (abductor pollicis longus, extensor
pollicis brevis) of the forearm in line with the second dorsal
compartment.Caremustbetaken to avoidinjury to the
superficial branch of the radial nerve as it pierces the fascia
and traverses dorsally.The plate is inserted between the ECRL
and ECRB tendons and gently passed under the outcroppers.
Remaining extra-articular,the plate should be advanced until it
is visualized in the distal incision.Occasionally,because of
dorsal fracture fragments or soft tissue obstruction, it will be
difficult to advance the plate past the carpus. In this case, athird
incision can be made over Lister’s tubercle to ease passage of
the plate under direct vision. This incision can also be helpful
with jointreductionand applicationofbonegraft later in
the case.
Once the plate is through to the distal incision, secure it to
the shaft of the index metacarpal with anon-locking screw.
Proper placement of anon-locked screw will effectively draw
the plate to the bone, eliminating any gap formation that may
occur between the plate and the bone if alocked screw is placed
first (Fig. 9). Using the C-arm, confirm that radial length has
been restored with the previously applied traction. If length has
notbeenrestored,the proximal aspect of theplate canbe
pushed distally in-line with the second metacarpal. With the
length appropriately restored, clamp the plate to the radial shaft
to secureits position. As with the metacarpal, insert anonlocked screw into the proximal most hole of the plate. The
remaining holes are filled with fully threaded, 2.4 mm bicortical
locking screws.
Frequently,the combination of traction and dorsal plate
placement restores radiallength, volartilt, and radialinclination. However,there are times when supplemental fracture
work must be undertaken after the spanning plate is applied.
In these cases, articular fragments can be elevated and defects
bone grafted through the incision located over Lister’s tubercle
(Fig. 10). Most intercarpal injuries can also be addressed through
this sameincision. Percutaneous K-wires along withscrews
placed throughthe mid-portionofthe plateoverlyingthe
distal radius can be implemented to augment fracture fixation
and stability.Any unstable volar shear or volar medial fragments must be buttressed through aseparate volar incision.
Prior to completion of the surgery,the DRUJ should be
inspected for any signs of instability.Volar and dorsal excursion
of the distal ulna in relation to the distal radius should be
checkedinneutral,pronated,and supinated positions.
Attempts at reconstructingthe triangular fibrocartilage
complex or stabilizing ulnar styloid fracturesshould be undertaken if theDRUJisindeedfound to be unstable andthe
patient’s conditionallows.Patients whocannottolerate
prolonged procedures should have the ulna pinned directly to
the radius just proximal to the DRUJ with two 0.62 in. K-wires.
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POSTOPERATIVE PROTOCOL/REHABILITATION
Patients without DRUJ instabilityshouldbesplintedpostoperatively for approximately10to14daystoallow soft
tissue healing. Our standard protocol is to place the patient
in along-armplaster splint,but aforearm-based splintis
acceptable for the compliant patient. Immediately postoperatively,both active and passive finger range of motion is started.
Furthermore, the patient is allowed to bear weight through
the forearm and elbow as needed for transfers and ambulation
with aplatform crutch. Lifting and carrying is allowed in the
immediate postoperative period but is limited to 4.5 kg until
the fracture has healed radiographically.
At the 10- to 14-day mark, forearm rotation and DRUJ
stabilityare once againassessed. Splintsare discontinued
altogether if forearm rotation is achieved with little effort and
the DRUJ is stable. Patients are allowed to begin gentle axial
loading of the wrist at this time. This axial loading is advanced
at the one-monthmarkand patients arepermittedto
FIGURE 5 Two examples of available bridge plates for distal radius
fractures. The titanium Arbeitsgemeinschaft fu¨rOsteosynthesefragen
(AO) mandibularreconstruction plate (*) has blunted ends with scalloped
edges. The AO distal radius bridge plate has tapered ends and beveled
edges.
Spanning Plating for Distal Radius Fractures
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155
discontinue the platform attachment and begin weight bearing
through the handgrip of their crutch.
If at the 10- to 14-day mark, the patient has difficulty with
supination or the DRUJ was repaired at the time of the initial
surgery,the patient is placed in aremovable long-arm splint.
This splint is fabricated in our occupational therapy department.The splintholds theforearm supinatedand canbe
removed for showering and range of motion exercises. The
splint is continued for an additional three weeks or until five
weeks postoperatively.Patients who required pins across their
DRUJ have the pins removed at the three- to six-week mark and
are kept in aremovable long-arm splint for an additional two
weeks. The timing for pin removal is based on the amount of
DRUJ instability noted at the time of the index procedure.
If supplemental K-wires were left outside of the skin, they
should be removed at six weeks postoperatively.Ifthe K-wires
have been cut short and left under the skin, they can be removed
at the time the spanning plate is removed assuming that they
are not irritating the patient excessively.Generally,the spanning
plate can be removed between three and four months postoperatively when the fracture has healed both clinically and
radiographically.After plateremoval, hand therapy should
focusonstrengthening and regainingwrist flexion and
extension.
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COMPLICATIONS AND THEIR MANAGEMENT
Complications with this technique are generally few.Aswith
any surgery,infection is always aconcern. However,uptothis
point, reported infections have only been superficialand
responsivetoantibiotics. There have been no cases of osteomyelitis. Three patients reportedly had an extension lag of 158 in
the long finger after plate placement (31). Ultimately,inevery
case, the extension lag improved to less than 108 after plate
removal. Twoother reported complications include abroken
plate and rupture of an ECRL (32). Both complications occurred
in acommercialfisherman who did not return to have his plate
removed in atimely manner.The patient returned at 19 months
after his initial surgery with broken hardware. At the time of
plate removal, the ECRL rupture was noted and treated with a
tenodesis to the ECRB. Anecdotally,wehave seen afracture in
the second metacarpal just distal to abridge plate. The fracture
occurred in avery osteoporotic female who fell approximately
two months after plate placement. The minimally displaced
fracture wastreated with splintingand wentontoheal
uneventfully.
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OUTCOMES
Several studies have validated internal distraction plating as an
excellent tool in the armamentarium for treatment of distal
(B)
(A)
FIGURE 6 ( A )Anteroposterior and ( B )lateral intraoperative radiographs demonstrating the initial reduction
obtained for acomminuted intra-articulardistal radius fracture utilizing traction and ligamentotaxis.
FIGURE 7 Intraoperative photograph demonstrating how abridge plate
can be superimposed over the wrist to help mark out incisions. Note the
sterile finger traps on the index and middle fingers.
156
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Lauder et al.
radius fractures. Shortly after Burke and Singer (9) demonstrated the technique of bridge plating, Becton et al. described
their own method implementing aspecialized plate designed to
simplify extra-articular insertion (33). Their technique involved
application of the plate under the second dorsal compartment
from the distal radius to the index metacarpal. Although their
plate cannot be converted into afixed-angle device and it is
too short for use in fractureswith meta-diaphyseal extension,
they reported good results in 35 patients. All fracturesunited
by eight weeks and they had no extensor tendon ruptures or
chronic regional pain syndromes (CRPS). Their two complicationsincludedloosening of metacarpal-sided screwsand
an indexfingermetacarpal fracture throughascrew hole.
The radiusfractures in thesetwo patients went on to heal
uneventfully.
In 2005 Ruch et al. reported on their technique for spanning
distal radius fractureswith a3.5-mm ASIF compression plate
(31). The study included 22 patients with high-energy injuries
that had extension into the metaphyseal–diaphyseal portion
of the distal radius. Plates were applied under the fourth dorsal
compartment from the distal radius to the metacarpal of the
long finger.The average time to fracture healing was 110days
and there werenononunions. At six months, patients averaged
578 /658 of flexion and extension and 778 /768 of pronation and
supination, respectively.Atthe one-year follow-up, 14 patients
wererated as excellent, 6asgood, and 2asfair according to the
Gartland and Werley rating system for distal radius fractures
(34). At an average of 24.8 months from surgery,DASH scores
averaged 11.5 (35). Complications werefew and included three
postoperative infections in patients with open fractures and
three mild extensor lags of the long finger that were noted to be
less than 108 at thefinalfollow-up.There werenotendon
ruptures,loss of reduction, or refractureafter plate removal.
Utilizing either 2.4 mm titanium mandibular reconstruction plates (Synthes) or 2.4 mm stainless steel DRB plates, Hanel
et al.reported theirresults for 62 patients whorequired
spanning of theirdistalradiusfractures (32).Platesinthis
study werepassed under the second dorsal compartment and
affixed to the shaft of the distal thirdofthe radius and second
FIGURE 8 X-ray demonstrating the use of fluoroscopy and the superimposedbridge plate to help with incision placement.
FIGURE 9 Intraoperative X-ray illustrating the use of anon-locked
screw to secure the plate distally. Usinganon-lockedscrew helps
draw the bone to the plate. Once locked screws are placed the plate is
essentially fixed in space.
Spanning Plating for Distal Radius Fractures
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157
metacarpal utilizing locking screw technology.All the fractures
went on to heal prior to plate removal, which averaged 112days
postoperatively.One patient broke his plate 16 months after
implantation. He was acommercialfisherman in Alaska who
returned to work with his plate in place. He returned at 19
months postoperatively forplate removal andhas since
returned to work.Ofthe 62 patients,41returned to their
previous occupation. It should be noted that 8ofthe remaining
21 patients were unemployed prior to their injuries. Of the 21
patients, who did not return to their prior employment, 13
sustained multipleinjuries necessitating drastic lifestyle
changes. No cases of postoperative CRPS or finger stiffness
werenoted in this study.
In unpublished data, Wolf et al. (36) assessed the rigidity of
locking bridge plates in acadaver model of unstable distal
radius fractures. They also compared this information to the
biomechanical stability of external fixators in the same fracture
model. Theauthors utilized 2.4mmspanningplateson10
specimens with 1cmofthe distal radius removed to simulate
an unstable situation. Importantly,itwas noted that locking
internal bridge plates with either four or three screws both
distallyand proximally were significantlymorerigid than
standard external fixation(p ! 0.05). Furthermore, there was
no statistical difference in stability between those osteotomies
stabilized with four screws both proximally and distally versus
thosesecured with athree screws on either side of the
simulated fracture.
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SUMMARY
The spanning internal distraction plate is auseful tool for many
distal radius fractures and it should have arole in any wrist
surgeon’s armamentarium. As an internal fixator this method
has many biomechanical and practical advantages to astandard
external fixator.Furthermore,bridge plating with its ease of
application, inherent stability,and need for minimal postoperative care, make it an ideal method of distal radius fixation in
patientswithmultiple extremity injuries and/or poor
bone stock.
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SUMMATION POINTS
Indications
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High-energy injuries in polytraumatizedpatients who
requireweight bearing throughthe upperextremities
for transfers.
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Osteoporotic fractures, with comminution,thatrequire
neutralization of the forces across the wrist.
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High-energy injuries with extensionintothe metadiaphyseal region.
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Fractures requiring bridging techniques in patients who
refuse external fixation.
Contraindications (Relative)
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Volar fracture fragments thatwillnot reduce
with ligamentotaxis.
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Dorsal soft tissue loss that would result in plate exposure.
Outcomes
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Average fracture healing times ranged from 60 to 110days.
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Majority of patients are able to return to previous work: 41
of 62 in one study.
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Average motion at six months postoperatively was 578 /658
of flexion/extension and 778 /768 of pronation/supination.
Complications
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Infrequent
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Extension lag of long finger
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Broken hardware
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Superficial infection
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ECRL rupture
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REFERENCES
1. Colles A. On the fractureofthe carpal extremity of the radius.
Edinburgh Med Surg J1814; 10:182–6.
2. Cooney WP,III, Dobyns JH, Linscheid RL. ComplicationsofColles’
fractures. JBone Joint Surg [Am] 1980; 62:613–9.
3. Altissimi M, Antenucci R, Fiacca C, et al. Long-term results of
conservativetreatment of fractures of the distal radius. Clin Orthop
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4. Fernandez DL. Reconstructive procedures for malunion and traumatic arthritis. Orthop Clin North Am 1993; 24:341–63.
FIGURE 10 X-ra ydemonstratingelevation of articularfragments
throughadorsalincision locatedoverLister’s tubercle.Afterthe
fragments are elevated bone graft should be used for support. The
bone graft can be supplemented with screws and/or Kirschner wires
and/or small plates.
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5. Knirk JL, Jupiter JB. Intra-articular fractures of the distal end of the
radius in young adults. JBone Joint Surg [Am] 1986; 68:647–59.
6. McQueen MM, Caspers J. Colles fracture: does the anatomical result
affect the final outcome? JBone Joint Surg [Br] 1988; 70:649–51.
7. Seitz WH .Complications and problems in the management of
distal radius fractures. Hand Clin 1994; 10:117–23.
8. Trumble TE,Schmitt SR, Ve dder NB. Factors affecting functional
outcome of displacedintra-articular distal radius fractures. JHand
Surg [Am] 1994; 19:326–40.
9. Burke EF,Singer RM. Treatment of comminuted distal radius with
use of an internal distraction plate. Te ch Hand Up Extrem Surg
1998; 2:248–52.
10. Hove LM, Furnes O, Nilsen PT,etal. Closed reduction and external
fixation of unstable fractures of the distal radius. Scand JPlast
Reconstr Surg Hand Surg1997; 31:159–64.
11.Kaempffe FA,Walker KM. External fixation for distal radius
fractures: effect of distraction on outcome. Clin Orthop 2000;
380:220–5.
12. Kaempffe FA ,Wheeler DR, Peimer CA, et al. Severefractures of the
distal radius: effect of amount and duration of external fixator
distraction on outcome. JHand Surg [Am] 1993; 18:33–41.
13. McQueen MM, Michie M, Court-Brown C. Hand and wrist
function after external fixation of unstable distal radial fractures.
Clin Orthop 1992; 285:200–4.
14. Nakata RY,Chand Y, Matiko JD, et al. External fixators for wrist
fractures: abiomechanicaland clinical study.JHand Surg[Am]
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15. Cooney WP.External fixation of distal radius fractures. Clin Orthop
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16. Leung KS, Shen WY,Leung PC ,etal. Ligamentotaxis and bone
grafting for comminuted fractures of the distal radius. JBone Joint
Surg [Br] 1989; 71:838–42.
17. Weber SC, Szabo RM. Severely comminuted distal radial fracture
as an unsolved problem: complications associated with external
fixation and pins and plastertechniques. JHand Surg [Am] 1986;
11:157–65.
18. AhloborgHG, Josefsson PO .Pin-tract complications in external
fixation of fractures of the distal radius. Acta Orthop Scand 1999;
70:116–8.
19. Parameswaran AD, Roberts CS, Seligson D, et al. Pin tract infection
with contemporary external fixation: how much of aproblem?
JOrthop Trauma 2003; 29:446–51.
20. Konrath GA, Bahler S. Open reduction and internal fixation of
unstable distal radius fractures: results using the Trimed fixation
system. JOrthop Tr auma 2002; 16:578–85.
21. Orbay JL, Fernandez DL. Vo lar fixationfor dorsally displaced
fractures of the distal radius: apreliminary report. JHand Surg
[Am] 2002; 27:205–15.
22. Axelrod TS ,McMurtry RY.Open reduction and internal fixation of
comminuted, intraarticular fractures of the distal radius. JHand
Surg[Am] 1990; 15:1–11.
23. Kambouroglou GK, Axelrod TS.Complicationsofthe AO/ASIF
titaniumdistal radius plate system (pi plate) in internal fixation
of the distal radius: abrief report. JHand Surg[Am] 1998;
23:737–41.
24. Orbay J. Vo lar plate fixation of distal radius fractures. Hand Clin
2005; 21:347–54.
25. Smith DW,Henry MH. Vo lar fixed-angle plating of the distal
radius. JAmAcad Orthop Surg 2005; 13:28–36.
26. Chapman MW,Gordon JE, Zissimos AG. Compression-plate
fixationofacute fracturesofthe diaphyses of the radius and
ulna. JBone and Joint Surg [Am] 1989; 71:159–69.
27. Duncan R, Geissler W, Freeland AE, et al. Immediate internal
fixationofopen fractures of the diaphysis of the forearm.
JOrthop Trauma 1992; 6:25–31.
28. Behrens F, Johnson WD ,Koch TW,etal. Bending stiffness of
unilateral and bilateral fixator frames. Clin Orthop 1983;
178:103–10.
29. Bartosh RA, Saldana MJ. Intraarticular fractures of the distal
radius: aCadaveric study to determine if ligamentotaxis restores
radiopalmar tilt. JHand Surg [Am] 1990; 15:18–21.
30. MedoffRJ. Essential radiographicevaluation for distal radius
fractures. Hand Clin 2005; 21:279–88.
31. Ruch DS, Ginn TA,Yang CC, et al. Use of adistraction plate for
distal radial fractures with metaphyseal and diaphyseal comminution. JBone and Joint Surg[Am] 2005; 87:945–54.
32. Hanel DP,LuTS, Weil WM.Bridge plating of distal radius
fractures: the Harborview method. Clin Orthop 2006; 445:91–9.
33. Becton JL, Colborn GL, Goodrich JA. Use of an internal fixator
device to treat comminuted fractures of the distal radius: report of
atechnique.AmJOrthop 1998; 27:619–23.
34. Gartland JJ, Jr., Werley CW.Evaluation of healed Colles’ fractures.
JBone Joint Surg [Am] 1951; 33:895–907.
35. Amadio P, Beaton D, Bombardier C, et al. Measuring disability and
symptomsofthe upper limb: avalidation study of the DASH
questionnaire.JEcon Med 1996; 14:11.
36. Wolf JC, We il WM, Hanel DP,etal. Abiomechanicalcomparison of
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Spanning Plating for Distal Radius Fractures
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20
Minimally Invasive Treatment of Distal Radius Fractures
with the MICRONAIL
VirakTan and John T. Capo
Department of Orthopedics, The New Jersey Medical School, University of Medicine and Dentistry of New Jersey,
Newark, New Jersey, U.S.A.
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INTRODUCTION
Fractures of the distal radius are common injuries. The extensive
varieties of fracture patterns and patient populations in which
they occur have led to the development of numerous treatment
strategies. The treatment options include cast immobilization,
percutaneous pinning (1), external fixation(2–4),internal
fixation with plates (5–16), and acombination thereof(17,18).
Management is based on the fracture pattern, degree of displacement,other associated injuries,and theindividualpatient’s
needs anddemands.Internalfixation of thesefractures has
grown in popularity with the recognition of the importance of
stable fixation and early motion of the involved extremity (19).
Although open reduction and internal fixation with metal
implants on the surface of the distal radius has allowed better
reduction of the fracture fragments and in many cases offer
moresecure fixation (5–16), it demands more extensive surgical
exposureand soft-tissuestripping.Furthermore,hardware
problems such as hardwareprominence and tendon irritation,
canoccur in times whichoften lead to removal of the
implant (7,8,11,12,15,16,19). The MICRONAIL (Wright Medical
Technology,Inc., Arlington, Tennessee, U.S.A.) is an intramedullary (IM) device that was designed specifically to provide
stable support of distal radius fractures while minimizing softtissue complications that can occur with internal and external
fixation implants (Fig. 1). The implant utilizes the principles of
load sharing, subchondral screw divergence, and locked fixedangle fixation. It is inserted through asmall skin incision at the
radial styloid and does not further devascularize the fracture
fragments. The limited surgical dissection and rigid fracture
fixation allow for minimal postoperative immobilization and an
early return of function.
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INDICATIONS
Overall, the indications for MICRONAIL use are generally the
same as for other distal radius fixation methods. Specific
indications for the MICRONAIL include distal radial metaphyseal fractures(i )where castingorexternal fixation is not
tolerated by the patient, ( ii)when reduction cannot be maintained by closed means, or ( iii)where early motion and return to
function is essential. Fracturepatterns that are amenable to this
form of fixation include extra-articular fractures (AO Types 1B,
1C) (20), intra-articular fractures with largefragments that can
be adequately reduced with closed or percutaneous methods
(AO Types B2, B3, C1, and C2), and distal radial metaphyseal
malunions.
Fractures with multiple comminuted articular fragments
(AO Type C3) may not be suitable for MICRONAIL stabilization
alone and may require supplemental fragment-specific fixation.
Other contraindications may include medicalcomorbidities,
patient refusal to undergo surgery,and active local infection.
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PREOPERATIVE PLANNING
The evaluation of adistal radius fracture is straightforwardand
is based on the history,physical examination, and imaging
studies. Important considerations in the history include age,
hand-dominance, occupation/vocation,and mechanism of
injury.Associated injuries in other areas of the body should
be ruled out when there is ahigh-energy mechanism. Examination of the injuredarm should include the elbow and forearm
in addition to the carpus, distal radius, and distal radioulnar
joint(DRUJ). Palpationmay elicit tendernessabout the
scaphoid, scapholunate interval, or distal ulna. Careful neurovascular examination must be performed with attention to the
median nerve, as acute carpal tunnel syndrome may develop
with displaced distal radius fractures(21–23). If there is an
associated operative injury about the wrist, it may need to be
addressed at the same time of the distal radius fixation.
Initial imaging studies should include orthogonal radiographs of all involved areas.For isolated injuries of the distal
radius, theindexradiographs shouldconsist of posterior–
anterior,lateral, and oblique views centeredover the wrist.
Additional studiessuchaspost-reduction radiographsand
computed tomography scans may be obtained for better visualizationofcomminutionorarticular involvement. Trac tion
X-rays areusefultodetermine thestability of thefracture
pattern and whether it is amendable to MICRONAIL fixation.
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SURGICAL TECHNIQUE
The surgical technique starts with astandard preparation of the
arm for wrist for surgery (24). An image intensifier is used to
confirm that anear-anatomic reduction is achievable by closed
manipulation. Afterthe tourniquetisinflated,a2to3cm
longitudinal incision centered over the radial styloid is made
in the skin (Fig. 2). Blunt dissection is performed through the
subcutaneous tissue and branches of the radial sensory nerve
are retracted from the surgical field. Dissection is then carried
down to the periosteum between the first and second dorsal
extensor compartments. The periosteumiselevated and
retracted. The fracture is provisionally reduced and stabilized
withKirschnerwires (K-wires) as needed (Fig. 3). In cases
where there are large articular fragments, especially on the
ulnar corner,temporary placement of K-wires may help maintain the reduction. Using acannulated drill, cortical window is
made at the tip of the radial styloid 2to3mm proximal to the
radioscaphoid joint line (Fig. 4). The starter awl is then introduced into the radial styloid in aretrograde fashion under
fluoroscopic guidance (Fig. 5). The fracture should be held in
areduced position as the awl is advanced into the metaphysis.
The awl is removed and broaching of the bone is begun.
With theaid of an image in te nsifier,the broach is guided
across thefract uresit eand advanced proximally into the
metaphyseal–diaphyseal bone (Fig. 6) by gently tapping the end
with asmall mallet. It is critical at this step to stay radial in the
canal in order to avoid penetrating the ulnar cortex of the radial
shaft. Sequential broachingisthen done to the point where the
broach does not spin within the medullary canal, using 2-finger
pressure. Care should be taken to avoid “over-rotating” during
the broaching. The broach should be inserted to the level of the
shoulder of the broach, to ensure proper depth below the radial
cortex. Once the bone has been broached to the appropriate size,
the actual implant, attached to the insertion jig, is advanced into
the bone until it is countersunk within the radial styloid. Position
of theMICRO NAIL should be confirmedwiththe image
intensifier.Satisfactory depth of insertion can be determined by
inserting aK-wire through the most distal hole of the device. The
wire should pass within the subchondral bone, approximately
2mmproximal to thearticular surface. Thedistal locking
buttressscrewsare no winserted after drilling throughthe
guides on the jig, thereby locking the distal bone fragment to
the nail. These screws also lock into the nail, creating afixedangle device.
Attentionisturnedtoplacementofthe proximalinterlockingscrews. Minoradjustmentsinradial length an d
inclination can be done at this time. Temporary K-wirescan be
(A)
(B)
FIGURE 1 Photographs of the MICRONAIL. ( A )Frontal view and ( B )
side view. Source:Courtesy of Virak Tan, MD.
FIGURE 3 Intraoperative posteroanterior fluoroscopic view of provisional stabilizationofadistalradius fracture with K-wireswires.
The K-wires are placed so that there is no obstruction to the path of
theMICRONAIL. Abbreviations :K-wires, Kirschner-wires. Source:
Courtesy of Virak Tan, MD.
FIGURE 2 Marking for incision over radial styloid ( arrow), between the
first and second dorsal compartments, for the entry point. The other
marking ( dorsal)isfor placement of the proximal interlocking screws.
Source:Courtesy of Virak Tan, MD.
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Tan and Capo
inserted through the jig and into the proximal fracture fragment
to maintain the final reduction. The proximal interlocking screws
are placed through asingle 2to3cm longitudinal incision on the
dorsum of the wrist, using the guide and sleeve provided. These
bicortical interlockingscrews secure the distal fragment-nail
construct to the shaft fragment. After the jig is disassembled,
final fluoroscopic images confirm the position of the implant and
the alignment of the fracture.The tourniquet is deflated, the
wounds are irrigated, and the skin is closed.
Postoperatively,for AO fracture types A2, A3, B2, B3, and
C1 no splinting is necessary; For AO types C2 and C3, the wrist
is splinted fortwo to fourweeks. Finger motion is started
immediately.Patients may performhomeexercises with
active finger (and wrist motion if not splinted) as tolerated.
At two to four weeks, any splint use is discontinued and home
therapy is progressed. The decision for formal supervised hand
therapy is individualized and based on the patient’s progress.
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Case Example
The patient is an 82-year-old right hand dominant female with a
history of poor vision and difficulty ambulating, who fell on her
outstretched right hand. She was found to have adisplaced
intra-articular AO Type C2 fracturewith an associated ulnar
styloid fracture (Fig. 7). Closed reduction was performed in the
emergencyroomand asugar-tongsplintapplied. Postreduction X-rays showed incomplete restoration of the radial
length and dorsal comminution in the metaphyseal bone. A
decision was made to perform operative stabilization of the
fracture in order to minimize her dysfunction and disability.
After medicalclearance, sheunderwentMIC RONAIL
fixation of the distal radius three days after her injury (Fig. 8).
The ulnar-sided dorsal fragment was percutaneously reduced
and provisional stabilized with aK-wire before instrumenting
for the MICRONAIL. After fixation, testing of the DRUJ showed
FIGURE 4 Intraoperative posteroanterior and lateral fluoroscopic views of acannulateddrill that is used to create
acortical window at the radial styloid, 2to3mm proximal to the radioscaphoidjoint line. This can be done under
hand power. Source:Courtesy of Virak Tan, MD.
FIGURE 5 The starter awl is introduced through the cortical window at
the radial styloid in aretrogradefashion under fluoroscopic guidance. It is
guided across the fracture site with the fracture in areduced position.
Source:Courtesy of Virak Tan, MD.
FIGURE 6 The broaching of the canal is done by gently tapping the end
with asmall mallet. Adequate broaching is achieved when the broach is
fullyseated within thecanal anditdoesnot toggle with “2-finger
pressure”. Source:Courtesy of Virak Tan, MD.
Minimally Invasive Treatment of Distal Radius Fractures with the MICRONAIL
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