Percutaneous Pinning of Distal Radius Fractures: An
Anatomic Study Demonstrating the Proximity of
K-Wires to Structures at Risk
Benjamin Chia, BA, Louis W. Catalano III, MD, Steven Z. Glickel, MD, O. Alton Barron, MD,Kristen Meier, BS
Purpose Closed reduction and percutaneous pinning is a reliable technique for treating 2- and3-part distal radius fractures. There are currently no data that demonstrate the proximity ofat-risk nerves and tendons during percutaneous placement of 5 commonly used K-wires.Whereas the previous literature notes the risk of superficial radial nerve injury with K-wireinsertion into the radial styloid, the current study provides specific distances, not only to thesuperficial radial nerve (SRN) but also to the tendons of the first through fifth extensorcompartments during K-wire insertion.
Methods K-wires (1.5 mm or 0.059 in) were placed percutaneously into the distal radius of15 cadaver specimens, simulating fixation of a distal radius fracture. After dissection, thedistance from the K-wires to the extensor tendons and branches of the SRN were measuredand tabulated.
Results The volar radial styloid K-wire was an average distance of 1.47 mm � 1.7 from theclosest branch of the SRN. One penetrated a branch of the SRN. The dorsal radial styloidK-wire was an average distance of 0.35 mm � 0.64 from the closest branch of the SRN. Notendons in the first compartment were found penetrated by or touching the K-wires. Thetransverse radial K-wire was an average distance of 1.07 mm � 1.57 from the branches ortrunk of the SRN. One K-wire was found piercing the volar branch of the SRN, and 1 K-wirewas found piercing the abductor pollicis longus. The dorsal rim K-wire was an average of2.94 mm � 2.11 from the ulnar aspect of the extensor pollicis longus and an average of 1.44mm � 1.65 from the radial aspect of the extensor digitorum communis. The dorsoulnarK-wire was an average distance of 1.88 mm � 1.6 ulnar or radial to the extensor digiti quintiproprius and penetrated it in three specimens.
Key words Anatomic study, cadaver, distal radius fracture, percutaneous pinning,superficial branch of radial nerve.
From the C.V. Starr Hand Surgery Center, St. Luke’s-Roosevelt Hospital, New York, NY.
Received for publication October 15, 2008; accepted in revised form April 7, 2009.
No benefits in any form have been received or will be received related directly or indirectly to the
Corresponding author: Louis W. Catalano III, MD, Department of Orthopaedic Surgery, ColumbiaCollege of Physicians and Surgeons; C.V. Starr Hand Surgery Center, Roosevelt Hospital, 1000 TenthAvenue, 3rd Floor, New York, NY 10019; e-mail: [email protected].
0363-5023/09/34A06-0006$36.00/0
subject of this article. doi:10.1016/j.jhsa.2009.04.004
MANY TECHNIQUES ARE used to treat displaced,unstable distal radius fractures. The currenttrend for treating displaced distal radius frac-
tures that require surgery is open reduction and internalfixation with volar plate fixation. However, several recentarticles have demonstrated complications with distal radiusplate systems including tendon ruptures, tenosynovitis, andadhesions.1–4 Closed reduction and percutaneous pinninghas been performed successfully for years with patientsexperiencing few complications,5–8 and, when complica-tions or infections do arise, removal of the K-wires hasbeen shown to help resolve the problem.9–12 In addition,closed reduction and percutaneous pinning is minimallyinvasive, simple, and cost efficient.9 Moreover, a recentCochrane Review documented no important differencesbetween distal radius fractures treated with open reductionand internal fixation or closed reduction and percutaneouspinning.13
Closed reduction and percutaneous pinning can beused to treat extra-articular and intra-articular fractures,classified as AO/ASIF type A2 and A3 and type C1 andC2. A minimum of 3 K-wires in an orthogonal config-uration, with 2 radial styloid K-wires and 1 or 2 fromthe dorsal rim of the distal radius just distal to Lister’stubercle, can provide reduction and stabilization of thefracture.14,15 However, some 3-part fractures may re-quire a transverse subchondral radial K-wire to buttressa depressed intra-articular fracture. A dorsoulnar K-wire is often used to fix a fracture of the dorsoulnaraspect of a lunate facet.9,12
K-wires that are placed for fixation are often in closeproximity to important structures such as the tendons ofthe first, third, fourth, and fifth extensor compartments andto the superficial branch of the radial nerve. There areseveral studies that note risk of injury to the superficialradial nerve during K-wire insertion.16–19 The currentstudy differs from previous studies in that it providesspecific distances not only to the superficial radial nerve(SRN) but also to the tendons of the first through fifthcompartments. The purpose of this study was to demon-strate the proximity to potential at-risk structures of 5K-wire entrance sites that are commonly used in a percu-taneous pinning technique. The 5 K-wire entrance sitesinclude a dorsal radial styloid longitudinal wire, volarradial longitudinal wire, transverse radial styloid wire, dor-sal rim K-wire, and a longitudinal K-wire at the dorsoulnarmargin of the distal radius.5–19
MATERIALS AND METHODSFifteen fresh-frozen cadaver upper extremities with anaverage age of 61 years were dissected after simulation
of our technique of percutaneous pinning. There were 6
JHS �Vol A, July
right and 9 left upper extremities from 8 men and 7women, with no evidence of disease or trauma. Theplacement of 5 percutaneous K-wires (1.5 mm; Syn-thes, Monument, CO) was performed via Small BatteryDrive (Synthes, West Chester, PA) under fluoroscopicguidance.
Three board-certified and fellowship-trained handsurgeons inserted the K-wires, obtained fluoroscopyimages, performed the dissections, and measured theappropriate distances. Each of the 3 surgeons was re-sponsible for 5 cadaver specimens each, resulting in atotal of 15 completed specimens. Percutaneous inser-tion of the K-wire was performed using standard ana-tomic landmarks and verified with fluoroscopy. All 5K-wires were inserted prior to dissection and removalof skin to ensure no movement of underlying structureswhen identifying structures. The technique used to sim-ulate the percutaneous pinning of a distal radius fractureis briefly described here and is explained in more detailelsewhere.9,12
Two radial styloid K-wires, volar (RS-V) or dorsal(RS-D) to the first compartment, were placed first. TheK-wires typically start in the radial styloid and aredriven across the fracture site into the proximal radialcortex. Use of 2 K-wires is standard for fixation of theradial styloid fracture fragment. The radial styloid K-wires were placed through the skin without an incision,assessed fluoroscopically to ensure correct anatomicposition at the tip of the radial styloid, and directed at anoblique angle toward the ulnar cortex of the radius witha K-wire driver.
A third K-wire, a transverse radial (R-Trans) K-wire,was driven transversely from the radial styloid acrossthe distal radial metaphysis just proximal to the sub-chondral bone. This K-wire is used clinically to buttressany depressed intra-articular fracture fragments. TheR-Trans K-wire is driven until it engages the ulnarcortex of the radius in the area of the sigmoid notch butdoes not extend beyond the cortex into the distal radio-ulnar joint.
The fourth K-wire, a dorsal rim (DR) K-wire, wasplaced perpendicular to the horizontal plane of the ra-dial styloid K-wires to provide orthogonal fracture fix-ation. We used a distance of 3.5 mm ulnar and justdistal to Lister’s tubercle to standardize the entry pointof the DR K-wire. The starting point on the dorsal rimof the distal radius was confirmed with fluoroscopy; theK-wire was then driven obliquely from dorsal to volarin a proximal direction to engage the volar cortex of theradius.
A fifth K-wire was then inserted at the dorsoulnar
margin of the distal radius (DU K-wire) to simulate
–August
ropos
1016 PINNING OF DISTAL RADIUS FRACTURES
fixation of a fracture fragment involving the dorsoulnaraspect of the lunate facet. The entry site is on the dorsalrim of the radius and is driven from dorsal to volar toengage the volar cortex.
Anteroposterior and lateral radiographs were ob-tained via C-arm fluoroscopy for each specimen toconfirm proper K-wire placement and direction (Fig. 1).
All dissections and measurements were done imme-diately after the placement of all 5 K-wires. Dissectionwas performed under 3.5� loupe magnification withcare taken to not disturb any of the anatomic relation-ships. Two incisions were used: a longitudinal incisionwas made centered over the radial styloid as well as astandard dorsal midline longitudinal incision. Measure-ments from the edge of the 3 radial K-wires to theclosest branch of the SRN and first dorsal compartmenttendons were performed first. Next, measurements fromthe DR K-wire to the extensor pollicis longus andextensor digitorum communis were performed and re-corded. Measurements were then taken from the edgeof the DU K-wire to the extensor digiti quinti propriusand extensor digitorum communis and recorded.
All measurements were obtained and recorded usingVernier digital caliper (no. 101-101; Tresna, Guangxi,China) with a resolution of 0.01 mm and an accuracy of�0.03 mm. The caliper, a light and durable handheldinstrument with sharp pinpoint caliper tips, was used tomeasure between the edge of the K-wire and the struc-ture at risk. Measurements were taken from the edge ofthe K-wire to the closest border of the tendon and/ornerve. A research assistant handled the caliper to main-tain consistency and correctly calibrate the caliper foreach measurement. Measurements were then averaged,and the range and standard deviation were calculatedusing Microsoft Excel (version 11.3.6; Microsoft, Red-
FIGURE 1: Radiographs showing A ante
mond, WA).
JHS �Vol A, July
RESULTS
The SRN was identified in all 15 of the specimens witha variable number of branches. In specimens with 2branches they were labeled as volar and dorsal and with3 branches as volar, middle, and dorsal. In 4 of the 15specimens, the RS-V K-wire was found touching abranch of the SRN. Three of the 4 RS-V K-wires werefound touching the volar branch of the SRN on theradial/dorsal border, and 1 K-wire was found touchingthe middle branch. In 1 of the 15 specimens, the RS-VK-wire was found piercing the volar branch of the SRN.No RS-V K-wires were found touching or piercing anytendons in the first dorsal compartment. The RS-VK-wire was an average distance of 1.47 mm (range, 0[touching or piercing a branch] to 5.13 mm; SD, 1.7)from the closest branch of the SRN. In 10 of the 15specimens, the RS-D K-wire was found touching thevolar, middle, and/or dorsal branch of the SRN. In 1specimen (Fig. 2), the RS-D K-wire was found betweenthe middle and dorsal branch of the SRN, touching butnot piercing both branches. The RS-D K-wire was anaverage distance of 0.35 mm (range, 0–1.76 mm; SD,0.64) from the closest branch (volar, middle, and/ordorsal) of the SRN. No tendons in the first compartmentwere found to be penetrated by the RS-D K-wire.
The R-Trans K-wire was in proximity to the trunkand branches of the SRN and to tendons of the firstdorsal compartment (Fig. 3). In 7 of the 15 specimens,the R-Trans K-wire was found touching a branch ortrunk of the SRN. Four of the 7 K-wires were foundtouching the trunk of the SRN. Of the 4 K-wires touch-ing the trunk, 1 K-wire was also found tenting the volaredge of the trunk of the SRN. Also, of the 15 speci-mens, 1 R-Trans K-wire was found piercing the abduc-
terior and B lateral views of a left wrist.
tor pollicis longus (Fig. 4), and in a separate specimen,
–August
PINNING OF DISTAL RADIUS FRACTURES 1017
1 K-wire was found piercing the volar aspect of thevolar branch of the SRN. The R-Trans K-wire was an
FIGURE 2: A lateral view of the radial aspect of a leftforearm. The dorsal radial styloid K-wire (black arrow) isbetween and touching the middle and dorsal branches of theSRN. The volar radial styloid K-wire (white arrow) istouching the volar branch of the SRN.
FIGURE 3: A lateral view of the radial aspect of a leftforearm. The black arrow points to a transverse radial K-wiretouching the volar aspect of the trunk of the SRN.
average distance of 1.07 mm (range, 0–4.74 mm; SD,
JHS �Vol A, July
1.57) from either the volar/dorsal branches or the trunkof the SRN.
The DR K-wire was in proximity to both the exten-sor pollicis longus and the extensor digitorum commu-nis. In 9 of 15 specimens, the DR K-wire was actuallycloser to the extensor digitorum communis than to theextensor pollicis longus (Figs. 5, 6). The DR K-wirewas an average of 2.94 mm (range, 0–7.55 mm; SD,2.11) from the ulnar aspect of the extensor pollicislongus and an average of 1.44 mm (range, 0–4.12 mm;SD, 1.65) from the radial aspect of the extensor digito-rum communis. In 3 of the 15 specimens, the DRK-wire was touching the extensor pollicis longus, andin 5 of 15 specimens, the DR K-wire was touching theextensor digitorum communis tendon.
The DU K-wire was in proximity to the extensordigiti quinti and extensor digitorum communis. On av-erage, in 15 specimens, the distance was 1.88 mm(range, 0–6.12 mm; SD, 1.6) ulnar or radial to theextensor digiti quinti proprius. In 4 of 15 specimens, theDU K-wire was ulnar to the extensor digiti quinti pro-prius, and in 8 of 15 specimens, the DU K-wire wasradial to the extensor digiti quinti proprius. The exten-sor digiti quinti proprius was penetrated by the DUK-wire in 3 of 15 specimens (Fig. 7). In 5 of the 15specimens, the DU K-wire was within 5.00 mm of the
FIGURE 4: A lateral view of the radial side of a right forearm.The thick black arrow points to the transverse radial K-wirepiercing the abductor pollicis longus (thin black arrow). Thetransverse radial K-wire was 4.74 mm dorsal from the trunk ofthe SRN (gray arrow).
extensor digitorum communis. On average, in the 5
–August
compartment.
the extensor digitorum communis tendons.
1018 PINNING OF DISTAL RADIUS FRACTURES
JHS �Vol A, July
specimens with K-wires in proximity to the ulnar sideof the extensor digitorum communis, the distance was2.27 mm (range, 0.65–4.41 mm; SD, 1.4).
DISCUSSIONThis study of the percutaneous placement of 5 K-wiressimulating pinning of a distal radius fracture in 15cadaver wrists demonstrates that nerves and tendons areat risk for injury. Several authors have reported resultson incidence of injury to nerves and tendons, compli-cations, and anatomic distances of K-wire placementthrough the radial styloid,5,6,7,8,14 but there are no ca-daver models that combine the study of 2 radial styloidK-wires, a transverse radial K-wire, a dorsal rim K-wire, and a dorsoulnar K-wire simultaneously. A ca-daver study by Hochwald et al. only used 2 K-wires,through Lister’s tubercle and the radial styloid, showingthe incidence of injury and distances to tendons andnerves. The study was a comparison of percutaneousinsertion of 44 K-wires at Lister’s tubercle and 44K-wires at the tip of the radial styloid and demonstrateda high incidence of displacement and piercing of nervesand tendons.16 Habernek dissected 10 cadaver handsafter drilling 3 K-wires and revealed the followingstructures exposed: the superficial radial nerve, the ce-phalic vein, and the tendons of the extensors. Theyfound in a follow-up of 80 patients no tendinous lesions
FIGURE 7: A dorsal view of a left wrist. The black arrowpoints to the dorsoulnar K-wire piercing the extensor digitiquinti proprius.
FIGURE 6: A dorsal view of a right wrist. Another example ofthe dorsal rim K-wire (black arrow) touching but not piercingthe extensor digitorum communis tendons of the fourth dorsal
FIGURE 5: A dorsal view of a left wrist. The thin black arrowpoints to the extensor pollicis longus; the dorsal rim K-wire(thick black arrow) was 4.48 mm perpendicular from the distalulnar edge of the extensor pollicis longus. The dorsal rim K-wire is in the fourth compartment touching but not piercing
(eg, tendon rupture) or serious complications.6 Stein-
–August
PINNING OF DISTAL RADIUS FRACTURES 1019
berg et al. studied placement of 3 K-wires through thesnuff box of 20 cadavers with only 1 entrance locationat the radial styloid and found the snuff box to be adangerous region for percutaneous hardware place-ment, with a high incidence of nerve injury. The studydefines a safe zone through the snuff box and estab-lishes a technique for percutaneous placement of hard-ware consisting of palpation, longitudinal stab incision,blunt dissection, and drill guide.17 This current cadaverstudy thoroughly documents the distances between 5frequently used K-wire entrance sites and the multiplestructures at risk. This differs from the aforementionedsources in that a dorsal radial styloid longitudinal wire,a volar radial styloid longitudinal wire, a transverseradial styloid wire, a dorsal rim K-wire, and a longitu-dinal K-wire at the dorsoulnar margin of the distalradius were all studied on a cadaver specimen in suc-cession.
Radial styloid K-wires: The common pattern of the SRNshown in a specimen in Figure 2 is similar to theconfiguration described in Abrams et al.20 Our findingscorroborate those of other studies that demonstrate SRNbranch damage caused from K-wires inserted into theradial styloid.16–19 Other studies have demonstratedthat multiple K-wires inserted into a single location canincrease risk of nerve injury.6,16 Because of this con-cern, the authors make a 1.5-cm incision over the radialstyloid prior to K-wire placement to avoid injury to theSRN branch or first compartment tendons.
Transverse radial K-wire: Like the radial styloid K-wires,the R-Trans K-wire is at risk to pierce the trunk orbranches of the SRN or tendons of the first compart-ment. Our results showed that the abductor pollicislongus and volar branch of the SRN could be injured.However, although it was found that 4 K-wires weretouching the trunk, no specimens showed the trunkbeing pierced. We recommend extending the radialstyloid incision proximally to minimize damage to ad-jacent nerves and tendons during placement of thesetransverse K-wires.
Dorsal rim K-wire: The distance of 3.5 mm ulnar fromLister’s tubercle and distal toward the dorsal rim wasused to avoid impaling the extensor pollicis longus. It ishypothesized that if the K-wire is inserted too close toLister’s tubercle, the extensor pollicis longus tendon isat risk of being pierced. Hochwald et al. also mentionthe risk of injuring the extensor pollicis longus whenusing the Lister’s tubercle as a “safe area.”16 The datadocumented in our study demonstrate that the DR K-wire was actually on average closer to the extensor
digitorum communis than to the extensor pollicis lon-
JHS �Vol A, July
gus. Care must be taken not to place the dorsal K-wiresmore than 5 mm ulnar to Lister’s tubercle to avoidextensor digitorum communis injury.
Dorsoulnar K-wire: When inserting the DU K-wire, theextensor digiti quinti proprius was at the greatest risk ofbeing injured. As the DU K-wire pierced the extensordigiti quinti proprius in 3 of the 15 specimens, thesurgeon should consider a small incision over the dor-soulnar radius prior to K-wire placement in thislocation.
The major study limitation was that these measure-ments were performed in specimens with an intactradius. Although the measured distances may change inthe setting of a fracture, the K-wires are inserted onlyafter an adequate reduction has been achieved. Anotherlimitation of the study is that 3 different surgeons per-formed the measurements. Prior to measurements, how-ever, the surgeons standardized the measurement pro-cess.
Not all of the 5 K-wires are necessary for fixation ofall fractures; the R-Trans K-wire is used to buttress anydepressed intra-articular fractures, and the DU K-wireis used to fix a fracture of the dorsoulnar facet of thelunate fossa. We chose to study all 5 K-wires in suc-cession to thoroughly evaluate all possibilities of frac-ture fixation.
We recommend a 1- to 2-cm incision just distal tothe radial styloid prior to insertion of the radial styloidK-wires. If an R-Trans K-wire is used, we recommendthat the surgeon extend the radial styloid incision prox-imally another 1 to 2 cm to protect the SRN andabductor pollicis longus. The DR K-wire must be be-tween 2 to 5 mm ulnar to Lister’s tubercle to avoidextensor pollicis longus or extensor digitorum commu-nis injury. Lastly, a 1- to 2-cm incision should beconsidered prior to placement of the DU K-wire toavoid injury to the extensor digiti quinti proprius ten-don.
ary to the AO/ASIF titanium distal radius plate without associatedplate failure: a case report. Am J Orthop 2000;29:789–791.
2. Schnur DP, Chang B. Extensor tendon rupture after internal fixationof a distal radius fracture using a dorsally placed AO/ASIF titaniumpi plate. Ann Plast Surg 2000;44:564–566.
3. Benson EC, DeCarvalho A, Mikola EA, Veitch JM, Moneim MS.Two potential causes of EPL rupture after distal radius volar platefixation. Clin Orthop Relat Res 2006;451:218–222.
4. Al-Rashid M, Theivendran K, Craigen MA. Delayed ruptures of theextensor tendon secondary to the use of volar locking compressionplates for distal radius fractures. J Bone Joint Surg 2006;88B:1610–1612.
5. Clancey GJ. Percutaneous Kirschner-wire fixation of Colles frac-
tures. A prospective study of thirty cases. J Bone Joint Surg 1984;66A:1008–1014.
–August
1020 PINNING OF DISTAL RADIUS FRACTURES
6. Habernek H, Weinstabl R, Fialka C, Schmid L. Unstable distalradius fractures treated by modified Kirschner wire pinning: ana-tomic considerations, technique, and results. J Trauma 1994;36:83– 88.
7. Mah ET, Atkinson RN. Percutaneous Kirschner wire stabilisationfollowing closed reduction of Colles’ fractures. J Hand Surg 1992;17B:55–62.
8. Kreder HJ, Hanel DP, Agel J, Mckee M, Schemitsch EH, TrumbleTE, et al. Indirect reduction and percutaneous fixation versus openreduction and internal fixation for displaced intra-articular fracturesof the distal radius: a randomised, controlled trial. J Bone Joint Surg2005;87B:829–836.
9. Glickel SZ, Patel MM, Catalano LW. Closed reduction and percu-taneous pinning for distal radius fractures. Atlas Hand Clin 2006;11:175–185.
11. Rosati M, Bertagnini S, Digrandi G, Sala C. Percutaneous pinningfor fractures of the distal radius. Acta Orthop Belg 2006;72:138–146.
12. Glickel SZ, Catalano LW, Raia FJ, Barron OA, Grabow R, Chia B.Long-term outcomes of closed reduction and percutaneous pinning
for the treatment of distal radius fractures. J Hand Surg. 2008;33A:1700–1705.
JHS �Vol A, July
13. Handoll HHG, Madhok R. Surgical interventions for treating distalradial fractures in adults. Cochrane Database Syst Rev 2003;(1):CD003209.
14. Naidu SH, Capo JT, Moulton M, Ciccone W II, Radin A. Percuta-neous pinning of distal radius fractures: a biomechanical study.J Hand Surg 1997;22A:252–257.
15. Rogge RD, Adams BD, Goel VK. An analysis of bone stresses andfixation stability using a finite element model of simulated distalradius fractures. J Hand Surg 2002;27A:86–92.
16. Hochwald NL, Levine R, Tornetta P III. The risks of Kirschner wireplacement in the distal radius: a comparison of techniques. J HandSurg 1997;22A:580–584.
17. Steinberg BD, Plancher KD, Idler RS. Percutaneous Kirschner wirefixation through the snuff box: an anatomic study. J Hand Surg1995;20A:57–62.
18. Glanvill R, Boon JM, Birkholz F, Meiring JH, van Schoor AN, GreylingL. Superficial radial nerve injury during standard K-wire fixation ofuncomplicated distal radius fractures. Orthopedics 2006;29:639–642.
19. Singh S, Trikha P, Twyman R. Superficial radial nerve damage dueto Kirschner wiring of the radius. Injury 2005;36:330–332.
20. Abrams RA, Brown RA, Botte MJ. The superficial branch of theradial nerve: an anatomic study with surgical implications. J Hand
