03-capo:capo 6-06-2012 11:51 Pagina 3 RivChirMano-Vol.49(1 ... · EXTERNALFIXATIONTECHNIQUESOFDISTAL RADIUSFRACTURES:DOESITWORKINPLATESERA? J.T. CAPO1, B. SHAMIAN1, M. RIZZO2 1DepartmentofOrthopaedics

EXTERNAL FIXATION TECHNIQUES OF DISTALRADIUS FRACTURES: DOES IT WORK IN PLATES ERA?

J.T. CAPO1, B. SHAMIAN1, M. RIZZO2

1Department of Orthopaedics - Division of Hand andMicrovascular Surgery - UMDNJ-New Jersey Medical School - Newark, NJ2Mayo Clinic, Department of Orthopaedics - Rochester,MN

Riv Chir Mano - Vol. 49 (1) 2012

SUMMARY

Fractures of the distal radius are common injuries. Low- or high-energy mechanisms may be involved. Unstabledistal radius fractures present a challenge to the treating orthopaedic surgeon. External fixation is a valuable in-strument for fracture reduction and stabilization. Limited open incisions, early range of motion and management ofcomplex wounds are a few of the benefits of external fixation. Fixators may be spanning or non-bridging, and maybe used alone or in combination with other stabilization methods to obtain and/or maintain distal radius fracturereduction. Augmentation with percutaneous wires is beneficial for optimal fracture stabilization. Moderate distrac-tion at the carpus does not create post-operative stiffness. The distal radioulnar joint must be assessed, and complica-tions of external fixation must be anticipated. In this manuscript we review the principles, indications, and tech-niques of external fixation, as it applies to the treatment of distal radius fractures.Riv ChirMano 2012; 1: 3-18

KEY WORDS

Digital radius fractures, external fixation, orthopaedic surgeons

Tecniche di fissazione esterna nelle fratture del radio distale: attuali anche nell’era delle placche?RIASSUNTO

Le fratture del radio distale sono lesioni comuni. Possono essere coinvolti meccanismi a bassa o ad alta energia. Lefratture instabili del radio distale rappresentano una sfida per il chirurgo ortopedico. La fissazione esterna è unostrumento prezioso per la riduzione e la stabilizzazione della frattura. Limitate incisioni aperte, un’iniziale rangedi movimento e gestione delle ferite complesse sono solo alcuni dei vantaggi della fissazione esterna. I fissatori pos-sono essere radio-radiale o radio-carpico, e possono essere usati da soli o in combinazione con altri metodi di stabi-lizzazione per ottenere e/o mantenere la riduzione della frattura distale del radio. L’aumento della stabilità con filipercutanei è vantaggiosa per la stabilizzazione ottimale della frattura. Una distrazione moderata del carpo noncrea rigidità post-operatoria. Deve essere valutata l’articolazione radio-ulnare distale e devono essere anticipate lecomplicazioni della fissazione esterna. In questo lavoro vengono rivisti i principi, le indicazioni e le tecniche di fis-sazione esterna e la loro applicazione al trattamento delle fratture del radio distale.

PAROLE CHIAVE

Fratture radio distali, fissatore esterno, chirurgia ortopedica

Corrispondence: John T. Capo,MD, 90 Bergen St, DOC 1200, Newark, NJ 07103 - Tel. 973 972-0763 - Fax 973 972-3897E- mail: [email protected]

INTRODUCTION

Distal radius fractures are extremely commoninjuries and tend to occur in a bimodal age distrib-

ution with a peak in younger patients and a secondpeak in older individuals. The mechanism of injuryis unique to each group, with high-energy injuriesbeing more common in the younger group and

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J.T. CAPO, B. SHAMIAN, M. RIZZO

low-energy injuries being more common in theolder group. They are also seen most frequentlyseen in children and again later in life in elderly,osteopenic women (1). Such injuries account forapproximately one-sixth of fractures treated in USemergency departments (27).Most distal radius fractures are low-energy frac-

tures, the result of a fall, and may be treated non-operatively with some form of closed immobiliza-tion. High-energy distal radius fractures are morecommon in younger adults. In each of these subsetsof patients the need for operative stabilization mayarise. The high-energy fractures frequently have ar-ticular comminution and displacement that requireopen means to reduce. A percentage of some of thecomminuted, osteoporotic low-energy fracturesmay be unstable injuries that require operative sta-bilization. The need for operative fixation of distalradius fractures in the elderly is becoming morecommon as the life expectancy in society increasesand the elderly population stays more active andphysiologically healthier.The use of external fixators in the treatment of

distal radius fractures is a common modality. Ex-ternal fixation can be used for various injuriesabout the wrist and in combination with other fix-ation methods (9). Currently the trend is towardsopen reduction and internal fixation and away fromexternal fixation. We believe the external fixator isa still a valuable tool for fracture treatment andthrough this review will demonstrate its effective-ness. This manuscript will focus on the differenttechniques of external fixation by reviewing thepeer reviewed literature and describing personaltechniques. We have focused our literature searchto peer review studies in the orthopaedic literaturethat have added clinically useful information to thecurrent state of external fixation.

PATHOPHYSIOLOGY AND ETIOLOGY

Distal radius fractures constitute up to 15% ofall extremity fractures (28). The mechanism of in-jury is usually a fall on an outstretched hand. Themost simple fracture mechanism is a bending frac-

ture, typical in an elderly woman. This usuallyleaves the articular surface intact but creates a frac-ture in the metaphysis. There may be a degree ofmetaphyseal comminution based on the amount ofenergy absorbed by the extremity. High-energyfractures can occur from various mechanisms, in-cluding falls from a significant height and motorvehicle accidents (5). These fractures can combinemetaphyseal and articular comminution. The distalradius has two articular surfaces, the radio-carpaljoint with the scaphoid and lunate facets, and thesigmoid notch that articulates with the distal ulna.Both of these articular surfaces must be realignedproperly for optimal function.

DIAGNOSIS

A distal radius fracture usually presents withpain and swelling at the wrist over the fracturedbone. There is often an angular deformity at thewrist, and it may assume the classic “dinner-fork”deformity with apex-volar angulation. Tendernessin the anatomic snuffbox should also be examinedfor, as fractures and dislocations of the carpus maycoexist with a distal radius fracture. Anteroposteri-or (AP) and lateral plain radiographs are usuallysufficient to characterize the distal radius fracture.If there is severe shortening of the radius or ulna,then an elbow radiograph should be obtained toevaluate for forearm instability or elbow fractures.Computed tomography (CT) scans of the radiusare occasionally helpful to learn more about the ar-ticular involvement of the radius. This informationmay help in planning operative approaches to bet-ter gain access to the most displaced and unstablefragments. Reduction of the distal radioulnar jointshould also be evaluated to ensure forearm stability.A triangular fibrocartilage injury may manifest it-self as distal radioulnar joint subluxation by show-ing dorsal displacement of the ulna (10). In a truelateral radiograph the pisiform sits between thevolar limits of the scaphoid and volar cortex of thecapitate. With this true lateral radiograph the dis-tal ulna sits in the dorsal half of the radius, withthe dorsal cortices co-linear.

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MANAGEMENT OPTIONS

Treatment options for the care of distal radiusfractures span a wide spectrum of operative to non-operative methods. For a nondisplaced extraarticu-lar fracture, a short arm cast may be sufficient. Asdisplacement increases, the need for closed reduc-tion increases. The exact values for inadequate re-duction are debated, and vary for age, handednessand occupation of the patient. Radiographic valuescan be used as guidelines for inadequate reductionof the fracture (Tab. 1) (8, 16).If closed reduction is successful in realigning the

fracture, then immobilization usually is extendedabove the elbow. This can be a long arm cast orsugar-tong type splint. Long arm immobilizationlimits rotation of the forearm and minimizes thepull of the brachioradialis. If closed reduction doesnot restore or maintain these alignment values,then operative intervention is warranted. Con-traindications for surgical repair include patientsthat cannot tolerate general or regional anesthesiaand poor bone stock that can not accept screws orpins for fixation. Some fractures may be deemedunstable at presentation. An unstable distal radiusfracture can be defined by several criteria (Tab. 2)(13, 17). The parameters usually represent mechan-ical instability, and often these fractures benefitfrom operative treatment. Closed treatment ofthese fractures have shown instability with a ten-dency to redisplace (13, 17).Other indications for operative treatment in-

clude: patients with lower extremity injuries whoneed weightbearing through the upper extremity;associated fractures of the ipsilateral upper extrem-ity that demand stable fixation of the radius to re-

habilitate the arm; and open injuries to allow prop-er treatment of the bony and soft-tissue injury.Operative management options may involve a

wide range of surgical techniques. These includepercutaneous pinning, external fixation, externalfixation augmented with K wires, intramedullaryfixation, and formal open reduction and internalfixation (ORIF) with plates and screws. Variouscombinations of the preceding methods can beused and give the surgeon great flexibility in hissurgical tactic.Regardless of the treatment option, Restoration

of the distal radius anatomy is crucial. Guidelinesfor acceptable reduction are (1) radial shortening<5 mm, (2) radial inclination >15°, (3) sagittal tilton lateral projection between 15° dorsal tilt and 20°volar tilt, (4) intra-articular step-off <2 mm of theradiocarpal joint, and (5) articular incongruity <2mm of the sigmoid notch of the distal radius (28).

SURGICAL TECHNIQUES

The goals of treatment of distal radius fracturesinclude: (1) restoration of length, (2) reduction ofarticular step off, (3) restoration of palmar tilt, (4)restoration of ulnar inclination, (5) and mainte-nance of a stable distal radioulnar joint. Externalfixation of distal radius fractures is a widely usedtool for initial or definitive management. The clini-cal situations where external fixator use is effectivein the wrist include several different fracture types

EXTERNAL FIXATION TECHNIQUES OF DISTAL RADIUS FRACTURES: DOES IT WORK IN PLATES ERA? 5

Table 1. Criteria for inadequate reduction after closed re-duction (8, 16).

Radiographic parameter Value

Articular step off >2 mmDorsal tilt >10 degreesRadial shortening > 5 mmUlnar inclination < 15 degrees

Table 2. Criteria for instability of distal radius fractures atpresentation (13, 17).

Radiographic parameter Value/Type

Comminution >50% from dorsal to volarAngulation >20 degrees dorsal tiltShortening >10 mmFracture Pattern Shearing, carpal fracture

dislocation (Barton’s)Combined pattern Radiocarpal fracture

dislocationDisplacement >100% loss of opposition

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(Tab. 3). The advantages of external fixators in-clude their ease of application, access to soft-tissue,and their versatility which easily allows combina-tion with other fixation techniques.Fixator frames function by maintaining length

and neutralization of compressive, torsional, andbending forces across the fracture site (3). Ligamen-totaxis is used for indirect reduction of fracturefragments. Distraction, ulnar deviation, and slightflexion can aid in reducing fragments that have cap-sular attachments. This can reduce large peripheralfragments but is ineffective in reducing impactedcentral (die-punch) articular pieces. Flexion alonecannot restore volar tilt as the dorsal capsular liga-ments are more expansile than the volar ligamentsand cannot rotate the fracture fragments effectively(2). With moderate distraction external fixators arean excellent method of unloading the carpus to al-low tenuous articular fragments, osteopenic meta-physeal bone and inserted bone graft to heal (4). Inrecent years the use of external fixator has decreasedin frequency and seems to be falling out of favor.However, the fixator is a technique that is wellproven in the orthopaedic literature and it shouldnot become a forgotten tool (7, 14, 21).

EXTERNAL FIXATION IN THE WRIST

The utility of external fixation includes the abili-ty to stabilize the fracture at a distance from thesite of injury, allow unimpeded access to the injurysite for wound care or additional procedures, ad-

justable length and alignment after application,and mobilization of the involved extremity. Therigidity of the fixator-bone construct increases withcrossbar proximity to the bone, pin-fracture prox-imity, increased pin diameter, and increasing pinspread. In addition, stacking of crossbars andplacement of pins in more than one plane also in-creases construct stiffness (3). These principlesshould be considered when using external fixationas a temporizing measure or definitive fracturemanagement. If the fixator is to be used only astemporary spanning frame or combined withORIF, then the radial shaft pins should be distantenough from the fracture site to allow plate place-ment away from the pin tracts.

BRIDGING EXTERNAL FIXATION

Radiocarpal spanning external fixation is a wide-ly used method of distal radius fracture stabiliza-tion. Ligamentotaxis is used to indirectly reducefracture fragments. Good and excellent results ofdistal radius fractures treated with unaugmentedexternal fixation have been reported (7, 26). Theamount of distraction applied and its effect onstiffness is a topic of much debate. In a recentstudy we evaluated the effects of distraction acrossthe wrist on the clinical outcome of 24 patientswith distal radius fractures treated with bridgingexternal fixator plus percutanous K-wires. We wereable to show that moderately increased distractionof the carpus at the initial fracture reduction is cor-

6

Table 3.External fixation uses in wrist injuries.

Purpose of fixator Reduction forces

Definitive reduction of fracture Length, moderate volar flexion, ulnar inclinationUnload carpus for ORIF of distal radius Length, axial distractionReduction tool for augmented fixation Overdistraction, hyperflexion and ulnar deviation; return to neutral

alignment after percutaneous pins placedStabilize carpal dislocations and ligamentous Length and neutral alignmentinjuries, sub-acute perilunate injuriesFracture stabilization during management Length and neutral alignmentof complex open wounds

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related with improved clinical outcome and doesnot have an adverse affect on subsequent wristrange of motion. Our data showed, based on func-tional rating by the Gartland and Werley evalua-tion system, 11 excellent, 10 good, 3 fair, and nopoor outcomes, for an 88% rate of good or excel-lent results (29).A standard technique for applying a bridging

external fixator is described below.Proximal threaded half pins, 3.0 to 4.0 mm, are

placed approximately one hand’s breadth proximalto the radial styloid tip, at the bare area of the radi-al shaft. This bare area lies just proximal to themuscles of the first and third compartments (theoutrigger muscles). A single 3 to 4 cm incisionshould be used for both proximal pins, with caretaken to identify and protect the tendons of themobile wad and the superficial branch of the radialnerve. Blind, stab incisions place these structures atrisk and are to be avoided. The extensor carpi radi-alis longus and brevis interval is used. This isslightly more dorsal than the brachioradialis exten-sor carpi radialis longus interval and thus lies fur-ther away from the superficial branch of the radialnerve. Also, this interval provides a tendon bufferon either side of the pins and has less nerve irrita-tion because the nerve typically exits between thebrachioradialis and extensor carpi radialis longus.These tendons are not usually irritated postopera-tively because the wrist extensors are immobilizedby the frame while the brachioradialis still hassome excursion. Distal pins are placed in the proxi-mal metaphyseal flare and shaft of the secondmetacarpal. These pins should have a smallerthread diameter (2.5 mm) to help avoid fracturingthe metacarpal. Open pin placement will helpavoid injury to the first dorsal interosseous muscleand dorsal branch of the radial artery. In addition,pins should not be transfixed into the thirdmetacarpal to avoid damage to the second in-terosseous muscle and the motor branch of the ul-nar nerve. Both sets of pins should be bicorticaland placed 45-degrees in the radial-dorsal plane.Placing the frame in this plane allows full retropul-sion of the thumb and aids in achieving unob-structed lateral radiographs (Fig. 1).

The most efficient technique is to next close allthe incisions at the pin sites. This is easier at thetime of pin insertion than at the close of the proce-dure where spanning bars and other exposed hard-ware make closure tedious. After pins and bars areplaced, but before tightening of clamps, the frac-ture must be reduced. It is tempting to apply trac-tion and excessive volar flexion to reduce the defor-mity of the usually dorsally displaced fracture.Volar flexion greater than 40° may be needed toobtain radiographic reduction. However, this de-gree of positioning results in elevated carpal tunnelpressures and may induce carpal tunnel syndrome(24). Instead traction, palmar translation and onlymild (<10°) flexion of the carpus should be applied.In addition, ulnar deviation should not exceed 20°because this may place excessive strain on the tri-angular fibrocartilage complex (9). If one cannotachieve fracture reduction within these parameters,then additional reduction or fixation techniques areneeded. A small subset of distal radius fractures canbe treated with a spanning, non-augmented frame.With this configuration, the fixator pins need to beclose to the fracture site to effectively control re-duction. At the close of the procedure, the positionof the wrist and degree of distraction must be criti-cally assessed. Flexion should not be more than 10°because this prevents power grip of the hand andcan induce median nerve compression. Full passiveflexion of the fingers into the palm should be easilyachieved. If this is impossible or the fingers havesignificant rebound, then the distraction is exces-sive and needs to be reduced. This prevention offlexion is caused by tension of the extensor digito-rum communis tendons and will seriously jeopar-dize final finger ROM. Examination of the finalfluoroscopy image should show even distractionacross all the carpal joints. There should not beasymmetrical widening of the midcarpal joint com-pared with the radiocarpal joint. This can also bemanifested as distraction of the scaphoid in rela-tion to the lunate, signifying a scapholunate tear.Again, distraction should be moderated if this isseen. In the AP and lateral views the carpus shouldbe concentrically reduced, with the lunate andscaphoid in there respective fossa.


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J.T. CAPO, B. SHAMIAN, M. RIZZO8

AUGMENTED EXTERNAL FIXATION

Distal radius fractures often require additionalfixation methods after placement of the externalfixator. The addition of K wires to an external fixa-tion construct has been proven in the lab to haveincreased rigidity (6, 25). In addition, the use of k-wires will likely help avoid loss of fracture reduc-tion over time. This may be required if fracture re-duction can not be obtained by ligamentotaxis withthe fixator alone, or if an excessive, non-physiologicposition of the wrist is needed for fracture reduc-tion. In this latter case the fixator can be used as aprovisional reduction tool. Often the fracture re-quires hyperflexion, ulnar deviation, and significantpalmar translation. After this is achieved the re-

duction can be held with crossed Kirschner wires(0.062” or 0.054”), one or two placed in the radialstyloid and an additional pin placed in the ulnarcorner of the radius. The radial side pins pass fromstraight radial to ulnar or slightly volar to dorsal,while the ulnar corner pin is placed obliquely fromdorsal to volar. Biomechanical investigations haveshown that crossed pins of a 0.062” size provideoptimal construct stability (20). Once the pins areplaced, the external fixator is adjusted back to amore neutral and physiologic alignment. Supple-mental Kirschner wires may also be used as a re-duction joy-stick to move articular fragments intoanatomic position before final pin positioning. Thistechnique can improve alignment of articular frag-ments in comminuted fractures (Fig. 2).

Figure 1. (A) The proximal fixator pins are placed throughone open incision. The pins are placed between the tendonsof the radial wrist extensors. The superficial radial nervecan be seen volar to this interval. (B) Half pins with a2.5mm thread diameter are placed in the second metacarpal.The proximal pin is placed at the metaphyseal flare and thedistal pin is placed in the shaft. (C) Placement of proximaland distal half-pins in a 45 degree dorsal-radial plane.

A

B

C

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Augmented fixation can also be beneficial dur-ing the postoperative course. With the presence ofdual fixation, either the fixator or K wires can beremoved earlier if they become problematic. Thiscan be especially helpful in the presence of a pintract infection or to initiate early range of motiontherapy. The fixator may need to be removed earlyif there is pin irritation or infection and some ofthe smooth pins can be left in place as early motionis begun. Augmented external fixation avoids openexposures to the distal radius and becomes an at-tractive option for unstable distal radius fractures.The ability of augmented external fixation to ob-tain good results has been well documented in theliterature (12, 23, 26).Zanotti et al. (26) prospectively studied the sub-

jective, functional and radiographic outcomes of20 patients with unstable distal radius fracturestreated with external fixation alone or in combina-tion with percutaneous pins. All patients weretreated with the Wrist Jack (Hand BiomechanicsLab, Sacramento, CA) adjustable external fixatorand followed up for a minimum of 2 years. Pins

and frame were removed, on average, approxi-mately 7 weeks postoperatively. Final intraopera-tive radiographs showed an average radial length,radial inclination and palmer tilt to be 11.1 mm,20.3°, and 6.5°, respectively. At final followup, fi-nal measurements for length, inclination, and tiltwere 12.3 mm, 18.7°, and 3.7°, respectively. Out-comes were rated as excellent in one patient, goodin 15 patients, fair in four patients, and poor innone.When analyzed by mechanism, patients whosustained a high-energy injury were more likely torequire supplemental fixation (percutaneous pins)and in general had a poorer outcome. Those withfair results were shortened an average radial lengthof 3.5 mm, a radial inclination of 12.3° and apalmer tilt of 4.5°. Restoration of length appearedto correlate with rated outcome. The authors con-cluded that external fixation with supplemental Kwires is a viable treatment option for high-energydistal radius fractures. However, modest resultsshould be expected for those patients with high-energy complex injuries, regardless of treatmentmethod.

Figure 2. (A) APview of distal radiusfracture treated withaugmented externalfixation. The carpusis reduced on the dis-tal radius and thereis no over-distrac-tion at the radio-carpal or midcarpaljoints. (B) Lateralview of the wrist inthe external fixatorshowing neutralalignment of thecarpus and goodrestoration of thevolar tilt of distalradius.

A B

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NON-BRIDGING EXTERNAL FIXATION

Nonbridging external fixation is a recently de-scribed technique for unstable distal radius frac-tures (11, 18, 19, 22). In theory, this method allowsfor more direct control of the distal fracture frag-ments, more stable fixation, and earlier, improvedROM of the wrist. The distal fragment is pur-chased with two threaded half-pins and can be ma-nipulated directly into flexion and ulnar deviation.The intervals used distally are typically betweenthe first and second compartments and in the thirdcompartment after retracting the extensor pollicislongus tendon. The pins are placed slightly conver-gent from dorsal to volar. A crucial element of thetechnique is to gain purchase in the volar cortex toincrease the moment arm for reduction of the frag-ment. The proximal pins are placed in a similar in-terval as a spanning frame but can be placed slight-ly more dorsal to attach the frame. A standard fixa-tor set can be used to connect the frame in a deltaconfiguration or a custom distal Y or T type clampcan be used to simplify the frame. Extra-articulardistal radius fractures are ideal situations for treat-ment with a nonbridging frame that can be madeinto a very low-profile design.Tapio et al. (22) treated 52 patients with a non-

bridging fixtor. Distal pins were inserted in the dis-tal radius via a transverse incision over the thirddorsal compartment. The fixator remained in placefor an average of 48 days; average followup was 16months. The authors reported good radiographicreduction and maintenance of reduction. Function-al results were good, with ROM and grip strengthrestored to approximately 90% the contralaterallimb. Somewhat surprisingly, however, subjectiveresults were less favorable, with 27 good, 11 fair,and seven poor results. This was perhaps secondaryto a relatively high (19%) infection rate and rela-tively short follow-up.

COMBINED TECHNIQUES

An external fixator can be used as one compo-nent in the fixation hardware of a distal radius frac-

ture. This is ideal for severe high-energy fracturesthat have metaphyseal and articular comminution.The external fixator is used to buttress the meta-physeal fragmentation while small plates or percu-taneously placed wires are used to align and fix thearticular fragments. Ideally, the fixator is placed firstin the standard 45° dorsal-radial position and trac-tion is applied. This position allows access for adorsal, volar, or radial approach to the radius. Ex-cessive traction and angulation can be applied tohelp align fragments for fixation by supplementarymeans. When the fragments are secured and bonegraft applied when necessary, then the fixator canbe backed off to a physiologic position. The tractionserves to provide mild distraction, which unloadsthe carpus from the distal radius. This fixator canbe removed early (3-5 weeks), because of the stabil-ity provided by the other hardware, and wrist ROMmay be initiated. High-energy distal radius fracturecan be effectively treated with a combination of ex-ternal fixation, volar plating, and percutaneous pin-ning (Figg. 3, 4).

STABILIZATION OF DRUJ

The importance of addressing the distal radioul-nar joint cannot be overstated. Indeed, distal ra-dioulnar joint injury occurs in approximately 10%of patients with distal radius fractures and is a ma-jor cause of discomfort after successful healing ofthese fractures (10). At the completion of distal ra-dius fixation, the distal radioulnar joint should beassessed for stability. This is done with elbowplaced on the hand table and flexed at 90°. The ra-dius is stabilized and the ulna is stressed volarlyand dorsally. This maneuver is done in neutral ro-tation and again in full pronation and supination.If there is abnormal translation or a significantclick or sense of subluxation, the distal radioulnarjoint should be stabilized. If the ulna is unstable ina dorsal direction then the forearm is placed insupination, if the ulna subluxates volarly thenpronation usually stabilizes the ulnar head. If ad-dressed acutely, the distal radioulnar joint can bereduced and immobilized by above elbow splinting

10

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Figure 3. A) AP and (B) lateral views of an open, severely comminuted and displaced distal radius fracture. C) AP and (D)lateral x-rays showing initial stabilization of an external fixator. The distal most, proximal pin is near the fracture site whichmay interfere with future plate placement.

BA

DC

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Figure 4. A) Intra-operative AP and (B) lateral x-rays demonstrating restoration of the joint surface with a small volar plateand additional percutaneous wires placed in the styloid. C, D) radiographs at 6 month follow-up showing healing of the frac-ture, reduction of the carpus and articular congruity at the distal radius.

BA

DC

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or casting. Alternatively the DRUJ can be immobi-lized with percutaneous ulno-radial pins (Fig. 5),or by inclusion of the ulna in the external fixatorconstruct (Fig. 6). Fixation of forearm rotationshould be maintained for 6 to 10 weeks, and thenprogressive motion is started under guidance of atherapist.If associated distal radioulnar instability is not

treated at initial injury, progressive subluxation ofthe ulna and joint incongruity with limitation ofactive rotation will soon develop. This problemwhen addressed chronically is much more complexand usually requires open reduction and ligamentreconstruction.

AFTERCARE

Pin tract irritation and infection may occur. Theimportance of daily pin care must be reinforced topatients. Care-givers responsible for elderly or in-firm patients must also understand the importanceof compliance with pin care. After the first postop-

erative dressing change, pin site care is begun.Cleaning is usually twice daily and can utilize ei-ther one-half strength hydrogen peroxide, alcohol,soap and water or saline. After the pin insertionsites are dry some practioners allow their patientsto shower with the external fixator.Equally important are daily exercises of the in-

volved extremity. Formal therapy is used in approx-imately 2/3 of our patients. The decision for thera-py is made in the first few weeks after fixation. Ex-ternal fixation across the wrist allows for early andfree digital and elbow ROM. Forearm rotation canalso be initiated if there is no distal radioulnar jointinstability. Non-bridging external fixators allow ad-ditional motion at the radiocarpal joint. The goal isto have complete digital and elbow ROM at thetime of fixator removal.

COMPLICATIONS

Complications associated with external fixationof distal radius fractures are common, ranging from

Figure 5. A) Lateral post-operative x-ray ofdistal radius stabilized with an external fix-ator demonstrating dorsal subluxations of theulna. The patient had a prominent distal ul-na and difficulty with forearm rotation. B)AP x-ray showing two 1.6 mm K-wiresholding the reduced DRUJ. C) lateral viewdemonstrating reduction of DRUJ.

A

B

C

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Figure 6. A) AP and (B) lateral view of a comminuted dis-tal radius fracture. C) Post-operative x-ray showing stabi-lization of fracture with volar plating, dorsal pin fixationand an external fixator. D) the external fixator construct isextended to the ulnar shaft with an outrigger bar to stabi-lize the DRUJ.

BA

D

C

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20 to 85% in published series (7, 21). The majorityof noted complications include minor pin tract in-fections and transient neuropraxias. However, moreinvolved infections requiring débridement are notuncommon, as are nerve irritation, tendon rupture,loss of reduction and complex regional pain syn-drome. Wrist and finger stiffness are also complica-tions that may be associated with external fixators.Harley et al. (12) performed a prospective ran-

domized trial comparing augmented external fixa-tion versus percutaneous pinning and casting forunstable distal radius fractures. Forty-one patientswere followed up for 6 months. They noted no dif-ference in clinical outcome between the twogroups, though they did note percutaneous pinsand casting were more likely to result in articulargaps and defects. There was a trend towards morefrequent pin tract infections, reflex sympathetic dy-strophy, and nerve injuries in the external fixatorgroup. One may conclude from this study that ex-ternal fixation, though minimally invasive, is not abenign procedure, and alternative treatment op-tions might be reasonable in the low demand or el-derly patient. Pins and casting has potentially few-er complications, but may result in an inferiorlong-term result in high demand patients. The twogroups had no difference in postoperative ROM.Kaempffe and Walker (19) have suggested a

causal relationship between fixator induced carpaldistraction and postoperative ROM deficits. Thisoften quoted study, however, did not show a statis-tically significant adverse effect of the amount dis-traction on functional outcome. Only duration ofexternal fixation was statistically correlated withdecreased wrist ROM. If properly used and exces-sive distraction is avoided, the fixator itself doesnot seem to lead to stiffness. When viewing thefluoroscopic view during the external fixator place-ment, the radiocarpal and midcarpal joints shouldhave similar and only mild distraction. It appearsthat stiffness in fractures treated by external fixa-tion is more a function of the injury rather than thedistraction induced by the fixator.Superficial pin tract infections after external fix-

ation are a well-known postoperative development.Most can be treated with meticulous pin care and

oral antibiotics. However, occasionally pin tract in-fections require débridement or fixator pin re-moval. In such cases, the presence of augmentationsuch as K wires can be very valuable for maintain-ing the reduction. The rate of pin tract infections,superficial and deep, is about 20% (21). Some haveadvocated delaying surgery 7 to 10 days before pinplacement to allow swelling to subside and poten-tially decrease the rate of pin tract infections, withrelatively lower rates of infection (26). The use of awrist splint to support the fixator may relieve someof the tension on the pins and help minimize pin-tract drainage and infection.Complex regional pain syndrome or neuritis also

can occur after external fixation of distal radiusfractures. Rates of 10 to 22% have recently been re-ported (4, 12, 18). It is unclear if this is due to thenature of the injury or a complication of the treat-ment. Also, the incidence of nerve irritation maybe significant but the occurrence of true complexregional pain syndrome is relatively rare. The im-portance of open pin placement cannot be over-stated. Others have implied that it is the degree ofthe soft tissue injury itself that is most directly re-lated to complications and therefore patient out-come (19).

DISCUSSION

Distal radius fractures are common fractures thatare seen in all age groups. These fractures representa large percentage of nearly all orthopedists’ clinicalpractice. The choice of the appropriate treatmentfor distal radius fractures depends on the personali-ty of the fracture and the patient, and also the ex-perience of the surgeon. Many fractures can betreated nonoperatively with alignment that is notideal, but that may provide function that is ade-quate for a low demand patient.As patients’ functional demands and activity lev-

el increase, the necessity for anatomic reduction ismore critical. External fixation is a tool that canhelp in achieving this required reduction. The useof an external fixator is often adequate by itself orcan be combined with other fixation methods. One


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of the advantages of standard external fixators isthe flexibility it provides with choice of pin place-ment location. Pins may be placed out of the zoneof injury, may be extended to the ulna to stabilizethe DRUJ or extended to different areas of thehand to fixate associated injuries. Through this re-view several conclusion can be made concerningthe use of external fixation in the wrist.Several clinical and biomechanical studies sup-

port the use of augmented fixation.The inability of ligamentotaxis via external fixa-

tion alone to restore distal radial volar tilt was de-scribed by Bartosh et al. (2) in the early 1990s andalso indicates the need for supplementary fixation.The biomechanics of augmented external fixationhas also been studied in the lab. Wolfe et al. (25)performed a cadaveric study comparing os-teotomized distal radii stabilized with external fix-ator alone or with various supplemental K wireconfigurations. Both fracture transfixion wires aswell as outrigger wires placed into the distal frag-ment and secured to the external fixator were supe-rior to external fixation alone in reducing fracturemotion. A single wire was enough to gain appre-ciable stability, and additional wires did not im-prove stability further.Early ROM is one of the goals after successful

fracture reduction and stabilization. However, anoverly aggressive approach to therapy may poten-tially lead to fracture motion and loss of reduction.The increased stability provided by augmented ex-ternal fixation and the ability to remove the fixatorearly and free the wrist joint assist in increasingeventual motion. Dunning et al. (6) studied unsta-ble cadaveric distal radius fracture stability by usinga computer-controlled wrist-loading device used togenerate simulated finger and forearm motions.Specimens were stabilized using spanning externalfixation with or without radial styloid pins or witha dorsal distal radius plate. They showed that sup-plemental K wires reduce fracture fragment motionwhen compared with external fixation alone. Thestability gained by this construct approached thatreached with dorsal plating technique.An alternate method of augmented external fix-

ation was recently described by Werber et al. (23)

They performed a randomized, prospective studycomparing external fixation of distal radius frac-tures using the standard four pin technique with afive pin external fixator that included an additionalpin placed in the radial styloid and attached to thefixator. Kirschner wires were used to help joy-stickfracture fragments but all supplementary wireswere removed at the end of the index procedure.Fifty patients were followed up clinically and radi-ographically for 6 months. The authors found thatthe five-pin fixator was better at restoring andmaintaining radial inclination, length, and volartilt. There was no difference in articular step-offbetween the groups. In addition, and most impor-tantly, the five-pin group had a better clinical out-come. These patients had better ROM, better gripstrength, and better overall clinical scores whencompared with the four-pin group.With this compelling evidence it seems prudent

to always combine a fixator with supplementarypercutaneous pins. The fracture is more directlyheld, and a more anatomic reduction can beachieved. The fixator can also be used as a reduc-tion tool as the pins are placed. With the pinsholding the fracture in a reduced position the fixa-tor can be backed off to a more physiologic posi-tion. This promotes early finger and elbow range ofmotion. With augmented fixation the spanningfixator can be removed at a relatively earlier time tobegin radio-carpal motion.The use of low profile and nonspanning fixators

decreases the complications and increases the toler-ance of frame wear. The literature has demonstrat-ed the improved effectiveness of non-spanningframes over spanning, non-augmented frames.McQueen (18, 19) supports the use of non-

bridging external fixation. She has reported im-proved initial and maintained reduction, and betterfunctional outcomes using this method. In aprospective, randomized study (18) of 60 patientswith unstable extra-articular distal radius fractures,the author was able to obtain an average of 5° volartilt using a nonbridging technique versus 3.6° dor-sal angulation in the spanning group. Importantly,in the nonbridging group, the reduction was main-tained at 1 year postoperatively, compared with the

16

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spanning external fixator group, where the reduc-tion deteriorated to an average of 12.2° apex volar.Radial length and alignment were also obtainedbetter and maintained in the nonbridging group. Inaddition, the nonbridging group was reported tohave better grip strength and ROM at final follow-up. However, the nonbridging group had two pa-tients with extensor pollicis longus ruptures, possi-bly because of irritation by the distal pins. Thiscomplication must be considered and emphasizesthe need for open pin placement, particularly withdistal radius pins. The spanning external fixatorgroup had two episodes of reflex sympathetic dys-trophy, whereas the nonbridging group had none.In a similar fashion to augmented fixation, non-

spanning frames have a more direct hold on thedistal fracture fragment. The application of non-spanning frames is technically demanding and of-ten the fragment can not adequately accept stan-dard half pins. Augmented fixation is technicallyeasier and appears to have similar results.The recent trend for fixation of distal radius frac-

tures has been towards more open reduction and in-ternal fixation with rigid plating systems. Lockedplates have been advocated for dorsal, volar or radialand ulnar column placement. These plating tech-niques have shown good results in the short term.However, there is a definite incidence of hardwareirritation, tendonitis and tendon rupture with allplating techniques in the distal radius. To adequate-ly compare the performance of external fixation ver-sus these modern plating systems a prospective ran-domized study comparing the two with similarfracture patterns should be undertaken.The external fixator is a technique that has been

well known to orthopaedic surgeons for many yearsand should not become a forgotten skill. With at-tention to the details of anatomy and fracture re-duction as described in this article, it can be a safe,effective, and useful tool.

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Documents

03-capo:capo 6-06-2012 11:51 Pagina 3 RivChirMano-Vol.49(1 ... · EXTERNALFIXATIONTECHNIQUESOFDISTAL RADIUSFRACTURES:DOESITWORKINPLATESERA? J.T. CAPO1, B. SHAMIAN1, M. RIZZO2 1DepartmentofOrthopaedics