REVIEW ARTICLE External Fixation of Distal Radius … ARTICLE External Fixation of Distal Radius Fractures David J. Slutsky, MD From the South Bay Hand Surgery Center, Torrance, CA

REVIEW ARTICLE

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External Fixation of Distal Radius FracturesDavid J. Slutsky, MD

From the South Bay Hand Surgery Center, Torrance, CA.

External fixation has been used for the treatment of distal radius fractures for more than50 years. Although the fixator configurations have undergone considerable modificationover time, the type of fixator itself is not as important as the underlying principles thatprovide the foundation for external fixation. Although volar plate fixation is currently invogue, the indications for external fixation remain largely unchanged. Newer fixatordesigns have also expanded the traditional usage to include nonbridging applications thatallow early wrist motion. The following discussion focuses on the myriad uses for externalfixation as well as the shortcomings and potential pitfalls. (J Hand Surg 2007;32A:1624 –1637. Copyright © 2007 by the American Society for Surgery of the Hand.)Key words: External fixation, radial, distal.

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here are some important anatomical pointsthat one must bear in mind when consideringexternal fixation of the distal radius. The ar-

icular surface of the radius is triangular, with thepex of the triangle at the radial styloid. It slopes involar and ulnar direction with a radial inclination of3° (range 13–30°), a radial length of 12 mm (range–18 mm), and an average volar tilt of 12° (1–21°).1

he dorsal surface of the distal radius is convex andrregular, and it is covered by the 6 dorsal extensorompartments. The dorsal cortex is thin, which oftenesults in comminution that can lead to an abnormalorsal tilt. Lister’s tubercle acts as a fulcrum for thextensor pollicis longus tendon, which lies in aroove on the ulnar side of the tubercle. The volaride of the distal radius, which is covered by theronator quadratus, is flat and makes a smooth curvehat is concave from proximal to distal. When insert-ng the dorsal pins, it is important to engage the volarlnar lip of the distal radius where the bone density isighest, especially in osteopenic bone.2

The dorsum of the radius is cloaked by the ar-orizations of the superficial radial nerve (SRN) andhe dorsal cutaneous branch of the ulnar nerve. TheRN exits from under the brachioradialis, approxi-ately 5 cm proximal to the radial styloid, and

ifurcates into a major volar and a major dorsalranch at a mean distance of 4.2 cm proximal to theadial styloid. Either partial or complete overlap ofhe lateral antebrachial cutaneous nerve with the
RN occurs up to 75% of the time.3 The dorsal l
624 The Journal of Hand Surgery

utaneous branch of the ulnar nerve arises from thelnar nerve, 6 cm proximal to the ulnar head, andecomes subcutaneous 5 cm proximal to the pisi-orm. It crosses the ulnar snuffbox and gives off 3 to

branches that supply the dorsoulnar aspect of thearpus, small finger, and ulnar ring finger. Open pinnsertion allows identification and protection of theseranches.The proximal pins are placed at the junction of the

roximal and middle thirds of the radius. At thisevel, the radius is covered by the tendons of extensorarpi radialis longus and extensor carpi radialis bre-is as well as the extensor digitorum communis. Theroximal pins can be inserted in the standard midlat-ral position by retracting the brachioradialis tendonnd the SRN, in the dorsoradial position between thextensor carpi radialis longus and extensor carpi ra-ialis brevis, or dorsally between the extensor carpiadialis brevis and extensor digitorum communis,hich carries less risk of injury to the SRN.4

igamentotaxisxternal fixation of distal radius fractures can besed in a bridging or nonbridging manner. Bridgingxternal fixation of distal radius fractures typicallyelies on ligamentotaxis to both obtain and maintainreduction of the fracture fragments. As longitudinal

raction is applied to the carpus, the tension is trans-itted mostly through the radioscaphocapitate and

ong radiolunate ligaments to restore the radial
ength. In a similar vein, pronation of the carpus can

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David J. Slutsky / External Fixation of Distal Radius Fractures 1625

ndirectly correct the supination deformity of theistal fragment.

imitations of Ligamentotaxisigamentotaxis has a number of shortcomings whenpplied to the treatment of displaced intra-articularractures of the distal radius. First, because ligamentsxhibit viscoelastic behavior,5 there is a gradual lossf the initial distraction force applied to the fractureite through stress relaxation.6 The immediate im-rovement in radial height, inclination, and volar tiltre significantly decreased by the time of fixatoremoval.7

Traction does not correct the dorsal tilt of the distalracture fragment. This is because the stout volaradiocarpal ligaments are shorter, and they pull out toength before the thinner dorsal radiocarpal ligamentsxert any traction.8 Excessive traction can actuallyncrease the dorsal tilt.9 A dorsally directed vector istill necessary to restore the normal volar angulation.his is usually accomplished by applying manual

humb pressure over the dorsum of the distal frag-ent. With intra-articular fractures, ligamentotaxis

educes the radial styloid fragment, but for the aboveeasons, it does not reduce a depressed lunate frag-ent.10 When there is a sagittal split of the medial

ragment, traction causes the volar medial fragmento rotate, which often necessitates an open reduction.xternal fixation cannot control radial translation;

herefore, it cannot be used with an unstable distaladioulnar joint.

iomechanicalonsiderations for External Fixationracture Site Loadsxternal fixation is considered flexible fixation.11

he biomechanical requirements of external fixationor fractures of the distal radius have not been ascer-ained because, until recently, the magnitude andirection of the physiologic loads on the distal radiusere dynamic and unknown. Recent work by Rikli

t al, however, has shed new light on this point.12

sing a new capacitive pressure-sensory device, hisroup measured the in vivo dynamic intra-articularressures under local anesthesia in the radioulnocar-al joint of a healthy volunteer. With the forearm ineutral rotation, the forces ranged from 107 N withrist flexion to 197 N with wrist extension. Theighest forces of up to 245 N were seen with therist in radial deviation and the forearm in supina-

ion. Presumably, any implant or external fixator
ould have to be strong enough to neutralize these (
oads in order to permit early active wrist motion.ikli et al also identified 2 centers of force transmis-

ion. The first center was opposite the scaphoid pole,hich would represent the radial column. The second

enter, which would represent the intermediate col-mn of the wrist, took a considerable amount ofhe load and was opposite the lunate, extending ul-arly over the triangular fibrocartilaginous complexTFCC).

ixator Frame Rigidityhe strength of the fixator depends on the rigidity of

he connecting rods and the clamps. Many externalxator rods are 0.5 to 1.0 cm in diameter, althoughadiolucent rods made from polyetheretherketones,ltem resin, or carbon fiber might be larger. Increas-

ng the diameter of the rods increases the rigidity byfactor of 4. Uniplanar fixators are common, but the

igidity of the construct can be increased by adding aecond parallel rod. Placing the rod as close to thekin as possible also increases the stability againstending loads by reducing the lever arm from theeutral joint axis. Most distal radius external fixatorsse 3.0 or 4.0 mm threaded half pins. Modernhreaded pins are hence designed with a larger coreiameter and smaller core-thread diameter. If the pinhreads are buried, the larger pin diameter at the nearone interface resists bending forces, whereas themall core thread resists pullout forces at the farortex. A bicortically inserted pin with a short threadill provide the best pin–bone fixation. Theoreti-

ally, under-drilling the pin hole by 0.1 mm provideshe best pin fixation with the least risk of boneesorption and pin loosening. It is also desirable topread the force evenly across the entire shaft of theone by creating a wide separation of the fixator pins.n order to achieve stable fixation and reduce theever arm of displacing forces, the pins should benserted close to the fracture site. One pin is hencenserted close to the fracture site, while the second islaced as far away as possible.13

onstruct Rigidityncreasing the rigidity of the fixator does not appre-iably increase the rigidity of fixation of the individ-al fracture fragments.14 There are a number ofays, however, in which to augment the stability of

he construct. After restoration of radial length andlignment by the external fixator, percutaneous pinxation can lock in the radial styloid buttress andupport the lunate fossa fragment.15 A fifth radialtyloid pin attached to the frame of a spanning AO
Synthes, Paoli, PA) external fixator prevents a loss

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1626 The Journal of Hand Surgery / Vol. 32A No. 10 December 2007

f radial length through settling and leads to im-roved wrist range of motion as compared to a 4-pinxternal fixator.16 The addition of a dorsal pin at-ached to a sidebar easily corrects the dorsal tiltound in many distal radius fractures.17,18

K-wire fixation enhances the stability of externalxation. The combination of an external fixator aug-ented with 1.6-mm (0.62 in) K-wires approaches

he strength of a 3.5 mm dorsal AO plate (Synthes,aoli, PA).19 Supplemental K-wire fixation is moreritical to the fracture fixation than is the mechanicaligidity of the external fixator itself.14 Stabilizing aracture fragment with a nontransfixing K-wire that isttached to an outrigger is just as effective as a-wire that transfixes the fracture fragments.20

ridging External Fixationemporary External Fixation: Indicationss compared to conventional plate fixation, bridging

xternal fixation can be used in a temporary mannerr it can be used for definitive management of theistal radius fracture. Bindra has listed the followingndications for this technique:21

. Initial management of severe grade open fractureswith extensive soft tissue loss

. Temporizing measure to resuscitate a polytrauma-tized patient

. Pending transfer to a tertiary referral facility fordefinitive fracture management

Rikli et al use temporary bridging external fixationor complex fractures to both aid in the provisionalracture reduction and to allow a better computedomography (CT) evaluation of the fracture charac-eristics prior to double plate fixation.22

efinitive External Fixation: Indications

. Unstable extra-articular distal radius fractures

. Two-part and selected 3-part intra-articular frac-tures without displacement

. Combined internal and external fixation

ontraindicationsridging external fixation should not be used as the

ole method of stabilization in the following situa-ions:

. Ulnar translocation due to an unstable distal ra-dioulnar joint

. Intra-articular volar shear fractures (Bartons, re-verse Bartons)

. Disrupted volar carpal ligaments/radiocarpal dis-
locations r
. Marked metaphyseal comminution

Combined index and middle finger metacarpalractures preclude the use of this technique due to thenterference with distal pin site placement.

omplicationsixator loosening with loss of fracture position cane avoided by periodically checking and tighteninghe fixator connections. Fixator failure by itself isncommon, but many commercially available fix-tors are approved for single use only due to the riskf unrecognized material fatigue or failure of anyocking ball joints. Pin site complications includenfection, loosening, and interference with extensorendon gliding. The risk of injury to branches of theuperficial radial nerve mandate open pin-site inser-ion. Bad outcomes associated with external fixationre often related to over-distraction. One biome-hanical study documented the effect of distractionf the wrist on metacarpophalangeal (MCP) jointotion. More than 5 mm of wrist distraction in-

reases the load required for the flexor digitorumuperficialis to generate MCP joint flexion for theiddle, ring, and small fingers. For the index finger,

owever, as much as 2 mm of wrist distraction sig-ificantly increases the load required for flexion athe MCP joint.23 Many cases of intrinsic tightnessnd finger stiffness that are attributed to reflex sym-athetic dystrophy are a consequence of prolongednd excessive traction, which can be prevented byimiting the duration and amount of traction andnstituting early dynamic MCP flexion splinting evenhile in the fixator.The degree and duration of distraction correlates

ith the amount of subsequent wrist stiffness.24 Dis-raction, flexion, and locked ulnar deviation of thexternal fixator encourage pronation contractures.istraction also increases the carpal canal pressure,25

hich may predispose to acute carpal tunnel syn-rome. Metaphyseal defects should be grafted toiminish bending loads and to allow fixator removalfter 6 to 7 weeks, which minimizes the fixatorelated complications.

esultsargaliot et al performed a meta-analysis of 46

rticles with 28 external fixation studies (917 pa-ients) and 18 internal fixation studies (603 patients).hey did not detect a clinically or statistically sig-ificant difference in pooled grip strength, wrist
ange of motion, radiographic alignment, pain, and

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hysician-rated outcomes between the 2 treatmentrms. There were higher rates of infection, hardwareailure, and neuritis with external fixation and higherates of tendon complications and early hardwareemoval with internal fixation. Considerable hetero-eneity was present in all of the studies, which ad-ersely affected the precision of the meta-analysis.26

Westphal and colleagues performed a retrospec-ive comparative study of 166 of 237 patients whoad surgery for AO/ASIF A3 or C2 distal radiusractures. The fractures were treated with either ex-ernal fixation or open reduction and internal fixationsing palmar or dorsal plates. Open reduction andnternal fixation, in particular palmar plate fixation,emonstrated the best radiological and functionalesults.27

External fixation falls short when used as the solereatment for displaced intra-articular fractures. In atudy of 27 patients with comminuted, displacedntra-articular fractures of distal radius that werereated exclusively by external fixation, Arora ando-authors concluded that although the external fix-tion is reliable in maintaining the reduction in dis-laced comminuted intra-articular fractures, it is in-dequate in restoring articular congruity in manyases.28

ugmented External Fixationhe use of supplemental K-wire fixation can expand

he indications for external fixation. As noted earlier,-wire fixation not only enhances the reduction of

he fracture fragments but also increases the rigidityf the entire construct. Many authors have stressedhe importance of using the external fixator as aeutralization device rather than as a traction device.igamentotaxis is used to obtain a reduction of the

racture fragments, which is then captured with per-utaneous K-wire fixation. The traction on the fixatoran then be reduced, which allows positioning of therist in neutral or slight extension.9 This serves to

educe extensor tendon tightness and facilitates fin-er motion. In a study of intrafocal pinning, Trumblend colleagues noted that in patients over 55 years ofge and in younger patients with comminution in-olving 2 or more surfaces of the radial metaphysisor �50% of the metaphyseal diameter) bridgingxation was necessary in addition to percutaneousin fixation to prevent late fracture collapse.29 In-part fractures where there is a sagittal split of theedial fragment, longitudinal traction accentuates

he palmar translation and rotation of the volar me-
ial fragment. Dorsal to volar K-wire placement car- r
ies the risk of injury to the volar neurovascularundles, especially with K-wire migration. For theseeasons, any sagittal split of the articular surfaceypically requires open treatment.30

ndications

. Intra-articular radial styloid fractures

. Three-part intra-articular fractures

. Following percutaneous reduction of a depressedlunate fragment

. Arthroscopic aided reduction of distal radiusfractures

ontraindications

. Marked metaphyseal comminution

. Volar/dorsal intra-articular shear fractures

esultsreder et al compared the results of open reduction

nd internal fixation (ORIF) versus external fixationnd pinning.31 A total of 179 adult patients withisplaced intra-articular fractures of the distal radiusere randomized to receive indirect percutaneous

eduction and external fixation (n � 88) or ORIFn � 91). There was no statistically significant dif-erence in the radiological restoration of anatomicaleatures or the range of movement between theroups at 2 years. The patients who had indirecteduction and percutaneous fixation, however, had aore rapid return of function and a better functional

utcome than those who had ORIF, provided that thentra-articular step and gap deformity were mini-ized.Grewal and co-authors noted the superiority of

xternal fixation and K-wire fixation over internalxation with a dorsally placed Pi plate for displaced

ntra-articular fractures of the distal radius. The plateroup also had higher levels of pain at 1 year whenompared with the external fixator group; however,his equalized after hardware removal. The externalxator group showed an average grip strength of7% when compared with the normal side versus6% in the dorsal plate group.32

omplicationsn one study of 70 cases of external fixation andercutaneous pinning, 34 cases lost more than 5° ofolar tilt following reduction at the 6-month fol-ow-up examination despite the use of pinning. Initialeformity, patient age, use of bone graft, and dura-ion of external fixation were not predictors of loss of
eduction. No specific predictor of loss of reduction

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as noted, although there was a trend toward a lossf reduction in younger patients.33

onbridging External Fixationridging fixation does not lend itself to early wristotion. Efforts to dynamically mobilize the wristith joint-spanning fixators have been largely unsuc-

essful. This is related to the difficulty in reproducinghe complex kinematics of the carpus, as well as thenability of the fixator to maintain ligamentotaxishroughout the entire arc of motion.34,35 Good resultsave been achieved with nonbridging fixation ofxtra-articular distal radius fractures, which does al-ow early wrist motion. The final wrist range ofotion and grip strengths are superior to those at-

ained with bridging external fixators.36,37

xtra-Articular Fracturesndicationsonbridging external fixation is indicated in any

xtra-articular fracture where there is a high risk of

igure 1. Biomechanical studies using the Fragment Specificixator (South Bay Hand Surgery LLC, Torrance, CA).

igure 3. (A) Displaced 3-part distal radius fracture. (B) Dorshe size of the medial fragment. (D) Lateral CT demonstraercutaneous reduction and application of nonbridging fixG) Coronal CT showing a congruent sigmoid notch. (H) Clin
xator. (J) Anteroposterior view after fixator removal at 6 weeks. (K
ate collapse. Lafontaine et al identified a number ofisk factors that were associated with secondary frac-ure displacement despite a satisfactory initial reduc-ion. These included the presence of dorsal tilt �20°,omminution, intra-articular involvement, an associ-ted fracture of the ulna, and age greater than 60ears. If 3 or more of these factors were present,here was a high likelihood of fracture collapse.38

hen there is significant displacement on the injurylms, there is a high likelihood of collapse even if the

nitial reduction is satisfactory. Trumble recom-ends supplemental internal and/or external fixation

n younger patients for fractures with �2 mm ofadial shortening and �15° of dorsal tilt following alosed reduction, especially if there is comminutionf 2 or more cortices.39 Although this is easier ifone early on, the fracture site can be still be freed upith a percutaneous elevator as late as 3 weeks,hich then allows a reduction of the distal fragmentsing the dorsal fixator pins.

ontraindicationsonbridging external fixation is contraindicatedhen the distal fragment is too small for pin place-ent. At least 1 cm of intact volar cortex is required

or pin purchase. Dorsal comminution does not pre-lude a successful result. This technique is not appli-able to volar displaced or volar shear fractures andn children with open epiphyses.40

igure 2. Cutaway view of sawbones demonstrating the 3-di-ensional pin fixation.

f the joint surface. (C) Anteroposterior CT scan highlightinge sagittal split of the medial fragment. (E) AP x-ray after

F) AP CT view demonstrating closure of the coronal gap.pearance of fixator after reduction. (I) Active wrist flexion in

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omplicationsin pullout due to fracture of the distal fragment canccur if the distal fragment is too small or osteopenicr if the reduction is too vigorous. If this occurs, thexator can be converted to a bridging construct. An

ncomplete reduction is also possible, especially withascent malunions. Over-reduction of the fracturean also occur, especially when there is volar com-inution.

esultscQueen et al performed a prospective study of 641

atients with unstable fractures of the distal radiusreated with external fixation. Of these cases, 378ere treated with nonbridging external fixation,ostly in AO type A3.2 and C2.1 fractures. Patients

reated with nonbridging external fixation had statis-ically significant better radiological results through-ut the period of review (p �0.001). In particular,his technique consistently restored the volar tilt andarpal alignment. Radiological improvement wasirrored by functional improvement. Most func-

ional indices were statistically better at an earlytage (p �0.040), whereas wrist flexion and griptrength remained significantly better at the finaleview (p �0.012). Complication rates were similaretween the 2 groups.40

ntra-Articular Fracturesarly wrist motion following intra-articular fracturesrovides a number of possible benefits, includingiminished stiffness, stimulation of cartilage repair,41

nd decreased osteopenia of the distal fragments.42

n order to accomplish this with nonbridging externalxation, the construct must be able to withstand theorces generated during active and passive wrist mo-ion.

iomechanical Considerationshe author undertook a biomechanical study to ex-mine the feasibility of nonbridging external fixationf simulated 3- and 4-part intra-articular fracturesDJ Slutsky, QG Dai, personal communication, Sep-ember 2003). The study was performed in 3 phases.n the first phase, this method was tested in a 3-partntra-articular fracture model using either 1 or 2

igure 4. Arthroscopic guided pinning and nonbridging exteB) Anteroposterior CT view reveals the extent of the intra-artihe degree of comminution. (D) Percutaneous reduction of dF) Fluoroscopic view after arthroscopic reduction. (G) Appli
estored radial height and tilt. (I) Congruent joint space with neutr
xternal fixators applied in a nonbridging fashion.ive fresh-frozen cadaver arms had biomechanical

esting using single and double nonbridging fixatoronfigurations. During the second phase, the maxi-um static force that could be withstood during

imulated passive-assisted wrist extension and simu-ated gripping without causing articular displacementn a 4-part fracture model was examined in 8 cadaverrms. All of the fractures were stabilized using aingle, custom, nonbridging external fixator, whichas an integrated dorsal sidearm (the Fragment Spe-ific Fixator, South Bay Hand Surgery LLC, Tor-ance, CA) (Fig. 1). In the third phase, the authorxamined the effects of cyclical loading on a 3-partntra-articular fracture model with dorsal comminu-ion as described by Dodds et al.43 All of the frac-ures were stabilized with the Fragment Specific Fix-tor.

The specimens were mounted vertically with an9-N (20-lb) preload 44 applied via gravity tractiony hanging 5-lb metal plates from the wrist tendons.ctive wrist motion was simulated by manually

anging the wrist through a complete flexion andxtension arc. Passive-assisted wrist motion was sim-lated by applying an additional load to the carpusith a servohydraulic materials testing machine (In-

tron 1321 Biaxial Hydraulic System, Instron Corpo-ation, Canton, MA). Gripping was simulated byirect axial loading of the lunate fossa. There was aide variation in the stiffness of the constructs dur-

ng phases 1, 2, and 3. Despite this, fragment-specificxternal fixation was able to maintain articular con-ruity with forces that exceed physiologic loading.he stiffness of the construct stabilized with the

ragment-specific fixator averaged 149 N in axialoading with an intact TFC and 117 N with a cutFC. These values compared favorably with thetiffness data of 5 commercially available distal ra-ius plates, which ranged from 95.5 N to 136 N. 45 Inhe third phase of the study, there was no observablerticular displacement in any of the wrists after 200ycles of wrist flexion and extension with loads of upo 145 N. The study conclusion was that nonbridgingxternal fixation with new fixator designs could bepplied to the treatment of intra-articular fractures.

xation. (A) Comminuted intra-articular distal radius fracture.ragmentation. (C) Arthroscopic view of joint surface showingtilt. (E) Arthroscopic view following reduction and pinning.of nonbridging external fixator. (H) Result at 6 months with

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utnam et al have shown that for every 10 N of griporce, 26 N is transmitted through the distal radiusetaphysis. They have recommended that the reha-

ilitation grip forces should be kept under 140 N withxternal fixation in order to prevent or minimize

igure 5. Volar plating with nonbridging external fixation. (A)nd dorsal tilt of articular fragments. (C) Volar and dorsal plateD) Lateral view shows reconstitution of joint surface “sandw

weeks. (F) Anteroposterior view at 8 weeks after fixator remoint reduction.

igure 6. Volar shear fracture with dorsal comminution. (A)-ray shows a volar shear pattern with dorsal comminution.olar articular fragment. (D) Lateral CT highlights the markeE) Distraction with joint bridging external fixation clarifies teduce the articular incongruity. (G) Volar locking plate app
ntermediate column. (I) Articular congruity is restored.
xation failure.46 This also appears to be a safe limits it pertains to nonbridging external fixation.

When using the Fragment Specific Fixator (Southay Hand Surgery LLC, Torrance, CA), the 3.0-mmxator pins are used in place of K-wires and have

articular fracture with metaphyseal extension. (B) Depressionn with application of uniplanar nonbridging external fixator.between volar and dorsal plates. (E) Clinical appearance at

(G) Lateral view demonstrating maintenance of a congruent

articular fracture with marked radial shortening. (B) Lateralteroposterior CT reveals an undisplaced sagittal split of the

iarticular dorsal comminution that precludes plate fixation.ture anatomy. (F) Ligamentotaxis alone, however, does noto the radial column. (H) Second volar plate applied to the

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ual roles. They provide interfragmentary fixation,ut when attached to the fixator, they also act likelade plates to resist bending moments and buttresshe fracture fragments (Fig. 2). The immediate sub-hondral position of the pins supports the joint sur-ace and is critical in maintaining articular congruityuring fracture healing. Ligamentotaxis through jointridging can be avoided in order to allow early wristotion. Similar to a fixed-angle plate, the biome-

hanical rationale for the Fragment Specific Fixators to transfer load from the fixed support of therticular surface to the intact radial shaft, bypassingny metaphyseal comminution. Unlike a fixed-anglelade plate, the fixator pin angle is freely adjustableo that it can be adapted to the fracture site plane,hich may diminish fracture malalignment.

ndicationsonbridging external fixation is ideally suited for the

reatment of 2- and 3-part intra-articular fractures ofhe distal radius provided there is good bone densitynd a stable distal radioulnar joint (DRUJ). Its useollowing an arthroscopic-aided reduction and K-ire fixation of an intra-articular fracture permits

arly, protected wrist motion, although bridging fix-tion is warranted in the presence of marked articularomminution (Figs. 3A–3K).

ontraindicationsolar and dorsal marginal fractures (Bartons and

everse Bartons) are excluded and should be treatedith internal fixation. Fractures with extensive me-

aphyseal/diaphyseal comminution require supple-ental internal fixation.

aveatsonbridging external fixation of intra-articular distal

adius fractures should be reserved for manually ac-ive patients with good bone quality and withoutvidence of prior wrist arthritis. The lunate fragmentust be sufficiently large to support two 3.0-mm

ins. A CT scan with anteroposterior, lateral, andoronal views is helpful to assess the fracture lineatterns in order to aid pin insertion.

omplicationshe immediate complications consist of injury toranches of the superficial radial nerve or dorsalutaneous branches of the ulnar nerve. Loss of fixa-ion due to poor pin placement or interference withxtensor tendon gliding can be minimized by carefulechnique and open rather than percutaneous pin
nsertion. The use of many standard external fixator r
rames applied in a nonbridging manner can result inrticular incongruity. Late collapse after fixator re-oval can occur in osteopenic bone, which often

equires subchondral support beyond the 6 weeks ofxator application. Due to the risk of late collapse,djuvant internal fixation with locking plates is ad-ised in elderly and osteopenic patients because frac-ure site settling may occur for up to 6 months.33

esultseports of nonbridging external fixation (or radio-

adial external fixation) for the treatment of intra-rticular fractures are sparse and mostly restricted tohe European literature. Krishnan et al reported alinical trial of 30 patients with Frykman type 7 andfractures who were treated with the nonbridgingelta Frame External Fixator (Mathys Medical Ltd.,ettlach, Switzerland).47 Although favorable wristotion was reported, the median intra-articular stepas 2.8 mm (range 0–9.1 mm) with a median intra-

rticular gap of 1.8 mm (range 0–13.4 mm).42

Gradl et al examined 25 consecutive patients withractures of the distal radius who were treated withonbridging external fixation for 6 weeks.48 Thetepwise surgical technique comprised a preliminaryoint-bridging construction for reduction purposes,he subsequent insertion of 3 to 4 K-wires in theistal fragment, the assembling of the K-wires to aorsal outrigger bar that was nearly parallel to theracture line, and finally the removal of the joint-ridging part. Clinical and radiologic evaluation waserformed on the first and seventh days, at 6 weeks,nd 2 years after surgery. All fractures united with aalmar tilt of �0° and articular step-off of �2 mm.loss of radial length occurred in 4 patients in which

nly 3 K-wires were inserted in the distal fragment.o radial shortening was seen in fractures with 4K-wires inserted in the distal fragment. The func-ional results at 2 years after surgery showed anverage extension of 55° and flexion of 64° withoutotable differences between extra-articular and intra-rticular fractures. There were no instances of exten-or tendinitis or pin loosening in the distal fragment;owever, there were 3 cases of proximal pin tracknfections.48

rthroscopic Assisted Reductionnd Nonbridging External Fixationndications

ore than 2 mm of articular displacement or gap areypical indications for surgical treatment. Isolated
adial styloid fractures and simple 3-part fractures are

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ost suited to this technique. Four-part fractureshould be tackled only after one has gained experi-nce with simpler fracture patterns. After reductionnd percutaneous pin fixation, many authors use aridging external fixator as a neutralization device orpply a volar locking plate. In many instances, it haseen my preference to use the Fragment Specificixator (South Bay Hand Surgery LLC, Torrance,A) in a nonbridging application to allow early wristotion (Figs. 4A–4I).

ontraindicationsarge capsular tears, which carry the risk of markeduid extravasation, active infection, neurovascularompromise, and distorted anatomy are some typicalontraindications. Marked metaphyseal comminu-ion, shear fractures, and volar rim fractures requirepen treatment, although the arthroscope can be in-erted to check the adequacy of the joint reduction.

lnar Styloidractures and DRUJ Instabilitylnar styloid fractures may or may not be associatedith disruption of the deep foveal insertion of theFCC and secondary DRUJ instability. Many au-

hors recommend initial fixation of the distal radiusracture and then assessment of the DRUJ for insta-ility because fracture reduction often restores DRUJnstability. If there is more than 5 mm of anteropos-erior displacement of the distal ulna during stressesting, wrist arthroscopy is beneficial. Basi-styloidractures carry the risk of TFCC detachment, but inn arthroscopic study of the soft tissue lesions asso-iated with distal radius fractures, Lindau noted thathe TFCC is more commonly avulsed off its radialnsertion.49 Any peripheral TFCC tear is repairedrthroscopically, using an outside-in technique. Ifhe articular disc has normal tension to palpation, thetyloid fracture is ignored or excised if there is theorry of late carpal impingement. The deep fibers of

he DRUJ can be directly assessed through a volarRUJ portal.50 If there is a disruption of the deepbers of the TFCC, an open foveal repair can beerformed.51 If the TFCC remains well attached tohe ulnar styloid fragment, ORIF of the styloid using-wires and tension band fixation, cannulated

crews, or bone anchors is performed.Ruch et al described the use of a dorsal outrigger

ttached to a bridging external fixator in cases ofssociated DRUJ instability.52 They found that pa-ients in whom the ulnar styloid can be reduced and
aintained in supination can be treated effectively t
ith fixed supination using an outrigger attached tohe external fixator. This method resulted in a statis-ically significant improvement in supination (p

0.05) as well as a lower rate of distal radioulnaroint complications, and it required fewer secondaryrocedures.

ombined Fixationombined fixation can be performed with the fixatorpplied in either a bridging or a nonbridging mode.n many instances, the Fragment Specific FixatorSouth Bay Hand Surgery LLC, Torrance, CA) ispplied in a nonbridging radial uniplanar configura-ion in conjunction with a combination of a volarnd/or dorsal plate (Figs. 5A–5G). In these instances,he fixator acts as a “third plate,” which replaces theadial styloid plate. Alternatively, this can be com-ined with a bridging uniplanar configuration whenhere is marked periarticular dorsal comminutionFigs. 6A–6I.).

ndicationsespite the plethora of volar plate designs, fixationf a small radial styloid fragment is often tenuous.he Fragment Specific Fixator can be applied in aniplanar radial application when there is a smalladial styloid fragment that cannot be adequatelyaptured with a plate. Any sagittal split of the medialragment that cannot be successfully reduced withercutaneous or arthroscopic methods is treated withragment-specific implants. Joint bridging fixation isndicated when there is central comminution to helpnload the articular fragments.

ontraindicationsnadequate or unstable soft tissue coverage orarked swelling would preclude the use of multiple

kin incisions and implants.

omplicationshe complications are similar to those describedarlier. There is a greater risk of hardware interfer-nce with tendon gliding and cutaneous nerveranches as the number of plates increase. The volarnd dorsal exposure can also devascularize smallragments that can lead to delayed healing or lateollapse, which is the rationale for the use of lockinglates rather than conventional mini-plates. In elderlyopulations with osteopenic bone, some fracture siteettling cannot be avoided, even following bonerafting, external fixation, and locking plates.Although it is currently not in vogue, ligamento-

axis still has its uses, especially in situations that

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ould preclude internal plate fixation. Novel fixatoresigns are opening new horizons, but multicenterlinical trials are necessary in order to determinehether the superior results obtained with nonbridg-

ng fixation of extra-articular fractures can be dupli-ated with intra-articular fractures. The combinationf external fixation with limited internal fixation is aseful adjunctive technique with multifragmentedractures. Gaining an understanding of the principlesnd limitations of external fixation allows one to beexible and adapt the fixation to the specific fractureattern in order to maximize the chances for ancceptable outcome.

eceived for publication June 4, 2007; accepted September 12, 2007.The author has an ownership interest in South Bay Hand Surgery LLC,

hich markets the Fragment Specific Fixator.Corresponding author: David J. Slutsky, MD, South Bay Hand Surgery

enter, 3475 Torrance Blvd., Suite F, Torrance, CA 90503; e-mail:[email protected] © 2007 by the American Society for Surgery of the Hand0363-5023/07/32A10-0019$32.00/0doi:10.1016/j.jhsa.2007.09.009

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Documents

REVIEW ARTICLE External Fixation of Distal Radius … ARTICLE External Fixation of Distal Radius Fractures David J. Slutsky, MD From the South Bay Hand Surgery Center, Torrance, CA