Learning Objectives: After reviewing the article, the participant should be ableto: (1) Describe the anatomy of the extensor tendons at the level of the forearm,wrist, hand, and fingers. (2) Recognize variations in the anatomy. (3) Master thehand examination and define the relevant findings in acute injuries of theextensor tendon(s). (4) Delineate the techniques for extensor repair in bothacute and secondary (delayed) management.Summary: Extension of the fingers is an intricate process that reflects thecombined action of two independent systems. The interossei and lumbricalsconstitute the intrinsic musculature of the hand. These muscles innervated bythe median and ulnar nerves extend the proximal interphalangeal and distalinterphalangeal joints and flex the metacarpophalangeal joints. The extrinsicextensors are a group of muscles innervated by the radial nerve, originatingproximal to the forearm. The extrinsic digital extensor muscles include theextensor digitorum communis, extensor indicis proprius, and extensor digitiquinti. The digital extensors function primarily to extend the metacarpopha-langeal joints, but also extend the proximal interphalangeal and distal inter-phalangeal joints. Normal extensor physiology reflects a delicate balance be-tween these two unique extensor systems. In the injured hand, a functioningintrinsic system may potentially compensate for an extrinsic deficit. An under-standing of the relevant anatomy and an appreciation for the complex interplayinvolved in extensor physiology is necessary to recognize and manage theseinjuries. (Plast. Reconstr. Surg. 121: 109e, 2008.)
ANATOMY
ForarmThere are two compartments of muscles, com-
prising a superficial layer and a deep layer. Themuscles of wrist extension, the extensor carpi ra-dialis brevis, extensor carpi radialis longus, andthe extensor carpi ulnaris, originate on the lateralcondylar ridge and lateral epicondyle of the distalhumerus. These muscles along with the extensordigiti quinti make up the superficial layer.
The deeper layer of muscles includes the fin-ger and thumb extensors. These muscles have abroad origin, including the lateral epicondyle, theproximal radius, the proximal ulna, and the in-terosseous membrane.1,2
WristThe tendons enter the hand through six com-
partments formed by the extensor retinaculum.The first compartment contains the extensor pol-licis brevis and the abductor pollicis longus; thesecond, the extensor carpi radialis longus and ex-tensor carpi radialis brevis; the third, the extensorpollicis longus; the fourth, the four tendons of theextensor digitorum communis plus the extensorindicis proprius; the fifth, the extensor digiti quinti;and the sixth, the extensor carpi ulnaris (Fig. 1).The extensor indicis proprius and extensor dig-iti quinti typically lie deep and ulnar to theextensor digitorum communis at the metacar-pophalangeal joints.
Disclosure: None of the authors has a financialinterest in any of the products, devices, or drugsmentioned in the article.
www.PRSJournal.com 109e
HandSeveral anatomical studies have analyzed the
extensor anatomy in zone VI, the dorsum of thehand. This area represents the region of greatestvariability in extensor anatomy. The juncturaetendinum or intertendinous connections are fi-brous connections between the extensor tendonsof the fingers proximal to the metacarpophalan-geal joints. There are three juncturae, which ex-hibit a high degree of variability. Junctura A con-nects the extensor tendons of the index and longfingers. Junctura B connects the long and ringfinger extensor tendons. Finally, junctura C con-nects the ring and small finger tendons (Fig. 2).Von Schroeder et al. classified the patterns of junc-turae tendinum into three types3: type 1, filamen-tous band; type 2, fibrous band; and type 3, ten-dinous band.
In a recent study, Hirai et al. analyzed 548 ca-daveric upper extremities and found the most com-mon pattern of intertendinous connections to betype 1 in the second intermetacarpal space and type3 in the third and fourth intermetacarpal spaces.4The functions associated with the juncturae includespacing of the extensor digitorum communis ten-dons, force redistribution, coordination of exten-sion, and stabilization of the metacarpophalangealjoints.5 A lacerated extensor tendon may be over-looked if digital extension is partially maintainedthrough intact juncturae tendinum. This often oc-curs in zone VI, where lacerations proximal to the
juncturae allow for retained function through anadjacent extensor digitorum communis tendon(Fig. 3).6
FingersThe extrinsic extensors are the sole extensors
of the metacarpophalangeal joint but can also pro-duce extension at the interphalangeal joints, pro-vided that hyperextension is controlled (Fig. 4).
Fig. 2. The three major juncturae tendinum of the hand link-ing the index to the middle fingers, and the middle to smallfingers.
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The extensor digitorum communis tendons passover the metacarpophalangeal joint and are heldin position by the sagittal bands. The sagittal bandswraps around the metacarpophalangeal joint toattach to the volar plate by an encircling series offibers by means of the transverse metacarpal lig-ament. It is this attachment that allows the exten-sor digitorum communis to extend the metacar-pophalangeal joint and thereby extending theproximal phalanx. These sagittal bands maintainthe extensor tendon in the midline over the meta-carpophalangeal joint and, along with the intrin-sic muscles, prevent hyperextension (Fig. 5).
Distal to the metacarpophalangeal joint, theextensor digitorum communis trifurcates. Thecentral portion continues distally and attaches
to the base of the middle phalanx (central slip).The central slip is joined by a medial band ofoblique fibers from the lumbricals and interos-sei. Together, they extend the proximal inter-phalangeal joint.7 The lateral slips of the exten-sor tendon pass on either side of the proximalinterphalangeal joint and join with the lateralbands of the intrinsic muscles to form the con-joined lateral bands. They reunite distally as theterminal tendon and insert into the distal pha-lanx (Fig. 6).
IntrinsicsThe interossei and lumbricals constitute the in-
trinsic musculature of the hand. The three palmarinterossei arise with a single head each from thesecond, fourth, and fifth metacarpals. The musclesare bipennate, measuring between 45 and 55 mm inlength.8 The volar interossei have no bony attach-ments; rather, they insert onto the lateral band anddorsal aponeurosis of the finger from which theyarise. They adduct and flex the proximal phalangesand extend the interphalangeal joints. The dorsalinterossei, apart from the third, have two musclebellies. The superficial or dorsal belly inserts ontothe base of the proximal phalanx. This belly func-tions as an abductor and weak flexor of the proximalphalanx. There is no direct effect on interphalan-geal extension. The deep or volar belly continues asthe lateral tendon and forms the lateral band of thedorsal aponeurosis. It flexes and abducts the prox-imal phalanges, and extends the interphalangealjoints. Both palmar and dorsal interossei pass dorsalto the deep transverse metacarpal ligament, whichseparates them from the lumbrical tendons.
The lumbricals are unique muscles in that theyarise from a flexor tendon and insert onto an ex-tensor tendon. They arise from the flexor digitorumprofundus and insert onto the radial band of eachfinger. The lumbricals function as the prime intrin-sic interphalangeal extensors.9 The exact action ofthe lumbrical is dependent on simultaneous con-traction or relaxation of its parent flexor digitorumprofundus. Flexor digitorum profundus contractionwill flex the interphalangeal joints, provided that thelumbrical relaxes. Conversely, lumbrical contractionwill produce interphalangeal joint extension if theprofundus tendon is relaxed. The interossei con-tribute to interphalangeal extension only when themetacarpophalangeal joints are flexed simulta-neously. The interossei, with their large cross-sec-tional area, are the predominant metacarpophalan-geal joint flexors.
Fig. 3. Laceration of the middle finger extensor digitorum com-munis (EDC) proximal to the junctura tendinum still allows forextensor digitorum communis extension by means of the junc-tura tendinum to the small finger.
brevis, and extensor pollicis longus tendons inserton the bases of the first metacarpal, proximal, anddistal phalanges, respectively (Fig. 7). The exten-sor pollicis longus tendon acts with relative inde-pendence across all three joints through the at-tachments of the dorsal apparatus. The tendon ofthe abductor pollicis brevis also forms a broadexpansion that fuses with the extensor pollicis lon-gus tendon. To this effect, the extensor pollicislongus is maintained in a central fashion by con-traction of the opposing muscle groups.10 In theevent the extensor pollicis longus is divided distal tothe metacarpophalangeal joint, it will be maintainedout to length by these attachments. The thumb hasno lumbricals or interosseous muscles. The only in-trinsic muscle function is derived from the adductormuscle and thenar muscles: the abductor pollicisbrevis, opponens pollicis, and flexor pollicis brevis.
ANATOMICAL VARIATIONSAnatomical variations in the anatomy of the
extensors are common.
First CompartmentGonzalez et al. reported septation in the first
compartment in 31 of 66 hands and multipleabductor pollicis longus slips in 38 hands. In thefirst dorsal compartment, septation occurs in 20to 60 percent of specimens. The abductor pol-licis longus may have multiple slips in 56 to 98percent of dissections.11
Second CompartmentWood reported the presence of a third radial
wrist extensor, the extensor carpi radialis inter-medius, in 12 percent of cadaveric specimens.12
Third through Fifth CompartmentsVon Schroeder and Botte detailed these varia-
tions in a cadaveric study. Common variations in theextensors to the fingers reported by von Schroederand Botte include a double extensor indicis pro-prius, double or triple extensor digitorum commu-nis to the long finger, single or triple extensor digi-torum communis to the ring finger, and single ordouble extensor digitorum communis to the smallfinger.
The extensor digitorum communis to the littlefinger may be absent in as many as 56 percent ofcases.13 In the case of absence of the little fingerextensor digitorum communis, a juncture fromthe ring finger will pass to the extensor hood at themetacarpophalangeal joint of the little finger.Gonzalez et al. noted that both the extensor digi-torum communis tendon and a junctura were ab-sent in 6 percent of cases.14 Transfer of the ex-tensor digiti minimi in these cases could result inloss of extension of the little finger.
In a separate study, Gonzalez and colleaguesidentified variations in the extensor indicis pro-prius in 19 percent of specimens. They noted du-plication of the extensor indicis proprius in 10 of66 hands and duplicate slips of the extensor digi-torum communis in two specimens.
ACUTE INJURIESKleinert and Verdan described a classification
system for extensor tendon lacerations accordingto eight zones in the hand, wrist, and forearm.15
Mallet Finger (Zone I)Green describes the hallmark of the mallet
finger as a loss of active extension at the distalinterphalangeal joint. The mechanism of disrup-tion involved in these injuries is most often a sud-den, forced flexion of the distal interphalangealjoint in an extended digit. The injury itself can beeither open or closed but is most often a closedinjury. These injuries are classified into four types:
Type I: Closed, with or without avulsion fracture.Type II: Laceration at or proximal to the dip joint
with loss of tendon continuity.Type III: Deep abrasion with loss of skin, subcu-
taneous soft-tissue coverage and, in addition,tendon substance.
Fig. 5. Extensor apparatus anatomy of the digit. EDC, extensordigitorum communis; MCPJ, metacarpophalangeal joint.
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Type IV:A. Transepiphyseal plate fracture in children.B. Hyperflexion injury with fracture of the ar-
ticular surface of 20 to 50 percent.
C. Hyperextension injury with fracture of thearticular surface usually greater than 50 per-cent and with early or late palmar subluxa-tion of the distal phalanx.
Management of these injuries is varied, rang-ing from simple immobilization to aggressive openreduction and internal fixation. Extension splintingof just the distal interphalangeal joint has becomethe standard of care for most mallet injuries (Fig. 8).Splinting is continuous for a period of 6 to 8 weeks.After this initial phase of continuous splinting, thepatient should be slowly weaned from the splint. Atthe first sign of regression (extensor lag), the patientshould be returned to continuous splinting. Mostauthors report a success rate of approximately 80percent with this strategy.
Indications for operative treatment are contro-versial. The three most common indications citedinclude (1) open injuries (types II and III), (2) thoseindividuals who are noncompliant or unable to tol-erate a splint, and (3) in cases where there exists alarge dorsal fragment with palmar subluxation of thedistal phalanx (type IV). Several techniques havebeen described for treatment of the mallet finger,including mattress sutures, pull-out wires, runningsutures or wires, and fixation with Kirschner wires(Fig. 9). Doyle describes Kirschner wire fixation ofthe distal interphalangeal joint for 6 weeks followedby nighttime splinting for 2 weeks.
Chronic Mallet FingerMany patients accept the deformity associated
with a mallet injury and never, in fact, seek medicalattention. The appearance alone, however, is of-ten enough for patients to seek treatment, evenseveral months after the initial injury. Other com-mon reasons patients may seek delayed treatmentinclude pain in the joint, secondary deformitiesincluding a swan-neck deformity, and a hookeddeformity in which the finger may get in the way.
Splinting should still be considered the first lineof treatment in those patients who present late. Sev-eral authors have provided evidence that immobili-zation, even in those patients presenting late, is al-ways beneficial.16–18 The initial work was performedby Abouna and Brown, in which 17 of 25 patientswith recurrent mallet deformities were treated withfurther immobilization. Their results demonstratedthat further immobilization is always beneficial, andthat the longer it can be maintained, the better theresult.
Surgery has traditionally been the therapy ofchoice for patients who initially fail conservativemanagement or for those individuals that presentwith recurrent, chronic mallet deformities. Thereare many surgical options that address the chronicmallet deformity. These include the following:
1. Immobilization with transarticular Kirsch-ner wire fixation across the affected joint.
2. Excision of tendon-scar unit and fixation inhyperextension.
3. Fowler’s central slip release.
Salvage techniques include distal interphalan-geal joint arthrodesis or amputation.
Middle Phalanx (Zone II)Injuries are typically seen with sharp lacerations,
saw injuries, and crush injuries. Doyle recom-mended a running core suture oversewn with aSilfverskiold epitendinous stitch. Acute lacerationswith extensor lag present on examination necessi-tate exploration and repair. Active extension withsome weakness against resistance is treated withsplinting for 3 to 4 weeks.
Proximal Interphalangeal Joint and BoutonniereDeformity (Zone I)
AbnormalityAbnormality begins with injury to the central
slip. Initially, active extension is retained by means ofthe lateral bands. Over time, however, the head ofthe proximal phalanx herniates through the centralslip defect, stretching or even tearing the triangularligament. The result is volar migration of the lateralbands. This, in effect, transforms the lateral bandsfrom proximal interphalangeal extensors into prox-imal interphalangeal flexors. In addition, the volarpositioning of the lateral bands increases the tensionon the bands, producing distal interphalangeal jointhyperextension. The initial deformity is often reduc-ible; however, without treatment, it rapidly becomesa fixed flexion deformity contraction. Green pro-vides three reasons for this contraction:
1. The transverse retinacular ligaments contract,holding the lateral bands in a fixed positionvolar to the proximal interphalangeal joint axisof rotation.
2. The oblique retinacular ligaments contractsimilarly, accentuating the distal interpha-langeal joint hyperextension.
3. The volar plate and accessory collateral lig-aments contract to create a fixed flexiondeformity at the distal interphalangeal joint.
Figure 10 demonstrates operative manage-ment of a chronic type 2 boutonniere deformity.
CauseCauses include the following:
1. Closed: includes crush injuries and volar dis-locations. The mechanism entails forced flex-
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ion of an actively extended proximal interpha-langeal joint, thereby detaching the centralslip and possibly avulsing the dorsal base of themid phalanx.
2. Open: involves laceration of the central slipand may include open wounds with tendonnecrosis and also burns.
3. Infected: subcutaneous and intraarticular in-fections with tissue necrosis or devitalizedtendon can result in disruptions of the cen-tral slip.
4. Inflammatory: rheumatoid arthritis andother inflammatory disorders are commonlyassociated with this deformity.
TreatmentThe treatment of acute injuries is designed to
prevent the boutonniere deformity. If a laceration
to the central slip is diagnosed at the time ofinjury, reapproximation of the central slip shouldbe undertaken. Closed injuries should be treatedwith splinting alone.
than 50 percent and complete lacerations arerepaired with a modified Kessler technique. Sev-eral studies have evaluated the various repairtechniques in zone IV. Newport and colleaguesdemonstrated that the modified Kessler stitchwould not shorten the tendon or limit flexion atthe proximal interphalangeal and distal interpha-langeal joints.19 The rehabilitation following repairis discussed below.
Fig. 8. Aluminum foam splint and stack splint for conservative treatment of a mallet deformity.
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Dorsal Hand (Zone VI)Injuries through or just distal to the juncturae
tendinum may be difficult to diagnose because ofthe minimal extensor lag associated with these in-juries. Injuries occurring proximal to the juncturaemay result in retraction of the proximal stump, mak-ing repair technically more challenging.
The tendons in this zone are very superficial,covered only with thin paratenon and scant sub-cutaneous tissue. Degloving injuries are not un-common and may require grafting, or local versusdistant flap coverage.
zone VII may have the worst prognosis. Injuries atthis level usually produce mass healing of tendonsto the underlying joint capsule and surroundingretinaculum. This may impair ultimate excursionafter healing and frequently results in a tenodesisof the tendons at the wrist.
Injuries in the wrist often necessitate releasingthe retinaculum for visualization and repair. At
least a portion of the extensor retinaculum shouldbe preserved to prevent bowstringing of the ten-dons. Early dynamic splinting may prevent or min-imize postoperative adhesions.
Forearm (Zone VIII)Injuries in the forearm may involve extensor
muscle bellies, tendons, or the musculotendinousjunctions. Actual muscle injuries should be re-paired with liberal figure-of-8 stitches. Both inju-ries should warrant static mobilization for 5 to 6weeks with the wrist extended to approximately 45degrees (see below).
REHABILITATIONConventional therapy has mandated immobi-
lization for acute extensor tendon repairs. How-ever, in recent years, the literature has supportedearly motion protocols after extensor tendon re-pairs. These protocols seek to promote tendongliding, achieve a return in extensor strength, andprotect the repair and prevent deformity and ex-tensor lag.
Zone INonoperative ManagementThe patient is placed in a volar static finger
extension splint with the affected digit in approx-imately 10 degrees of hyperextension. In the pres-ence of a pseudo–swan-neck deformity at the prox-imal interphalangeal joint, a tripoint splint can beincorporated into the distal interphalangeal joint.Immobilization is continued over a course of ap-proximately 6 weeks.
Exercises begin with blocking exercises of theprofundus, involving proximal interphalangealjoint active motion only.20 This regimen is contin-ued for approximately the first 6 weeks.
At week 6, gentle active flexion of the distalinterphalangeal joint is allowed to 30 degrees. Al-though full active extension is permitted, thereremains no passive flexion. At weeks 7 and 8, activeflexion is increased from 60 degrees to full. It is atweek 10 and beyond that resistive exercises arebegun. It is important to monitor for the presenceof extensor lag throughout this period.
Postoperative ManagementPostoperatively, the hand is placed in a hand-
based, static, volar positioning splint. The splintshould include the involved digit’s metacarpopha-langeal and proximal interphalangeal joints. Im-mobilization is constant over the first 6 weeks, withexercises not being started until the sixth andseventh weeks.
Fig. 9. Preoperative radiograph of a type IVB mallet injury fol-lowed by closed reduction and percutaneous pinning using theIshiguro technique.
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Fig. 10. Surgical correction of a chronic type 2 boutonniere deformity.
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Zone III
Stage I: Nonoperative ManagementThe affected digit is placed in a static finger
extension splint (Fig. 11). During the initial 6weeks, the proximal interphalangeal joint is im-mobilized completely. Exercises during this timefocus on the distal interphalangeal joint. Activeflexion and extension is repeated in the splint,with repetitions of 10 held for a count of 10seconds.
At week 6, the splint is modified to allow forproximal interphalangeal joint active flexion to 30degrees. Full active extension is permitted at thistime; however, there remains no passive flexion.Gradually, the range of motion is increased to fullover the course of the next 1 to 2 weeks. At week10 and beyond, graded resistive exercises are ini-tiated.
Stages II and III: Nonoperative ManagementThe following regimen may be initiated in the
clinical scenario in which there is tightness asso-ciated with the oblique retinacular ligament or inthe event that full passive proximal interphalan-geal joint extension is not attainable. Serial castsin extension are applied and changed frequentlyto stretch contractures until the affected joint ap-proximates neutral. The patient is asked to flex thedistal interphalangeal joint every 2 hours to keepthe oblique retinacular ligament stretched. Serialcasting may be required of the metacarpophalan-geal, distal interphalangeal, and proximal inter-
phalangeal joints in advanced stage II, zone IIIinjuries.
Postoperative ManagementThe affected extremity is placed in a hand-
based volar positioning splint with the involveddigit immobilized completely. During the initial 6weeks, there is complete immobilization of theaffected digit. The patient is simply monitored forsplint fit and wear.
At week 6, active flexion is initiated to 30 de-grees. At this time, full active extension is permit-ted. Again, no passive flexion is allowed at anytime. Over the ensuing 2 to 3 weeks, active flexionis increased gradually to full range of motion. Atweek 10, graded resistive exercises are initiated.
Zones IV and VIIPostoperative ManagementIt is imperative that the surgical team effectively
communicates and documents the exact type, loca-tion, and quality of the extensor repair. Likewise, itis critical to document the repair of any vessels ornerves that may affect the timing of rehabilitation.
Postoperatively, the patient is placed in avolar positioning splint. In the first 3 weeks,passive extension is allowed in the splint. In theevent of a six-strand repair, gentle active rangeof motion can be initiated early (as soon aspostoperative day 3).
At week 4, gentle active extension is moni-tored. Again, no passive flexion is allowed at anytime. In the next 2 weeks, active flexion is initiatedand graded resistive exercises are added to theregimen. During the entire time, the patient isevaluated continuously for the presence of exten-sor lag.
Zones V and VIEarly MobilizationAfter repair of the extensor tendons, the pa-
tient is placed in a dynamic extension splint forearly mobilization (Fig. 12). During the initial 4weeks, the patient is allowed to perform activeflexion to 30 degrees of metacarpophalangealjoint motion with passive extension by means ofrubber band traction. The range of motion is in-creased gradually over the ensuing several weeksto full by week 5. After 5 weeks, the dynamic ex-tension splint can be discontinued, provided thereis no extensor lag or other complications presentto interfere with motion. Once the splint is dis-continued, the patient may begin active extensionand flexion. Eventually, graded resistive exercisesare begun to augment strength and mobility.
Fig. 11. Conservative treatment of a boutonniere deformitywith proximal interphalangeal joint splinting.
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Mowlavi et al. studied dynamic versus staticsplinting of simple zone V and zone VI extensortendon repairs. In a prospective, randomized, con-trolled study, they demonstrated that dynamicsplinting provided improved functional outcomesat 4, 6, and 8 weeks when compared with staticsplinting. However, there was no difference at 6months and beyond. The authors therefore con-cluded that dynamic splinting should be offered toselect patients who are motivated and desire ear-lier return to full functional capacity.21
Thumb (Zones I through III)The affected extremity is initially placed in a
thumb spica splint. During the first 3 weeks, thewrist is positioned to 30 degrees of extension. Thethumb, carpometacarpal, metacarpophalangeal,and interphalangeal joints are all held in an ex-tended manner (Fig. 13).
At week 3, gentle active extension of the in-terphalangeal, metacarpophalangeal, and carpo-metacarpal joints of the thumb is initiated. Atweeks 4 to 5, there is continued gentle active ex-tension with the addition of gentle active flexionof the same joints. At week 6 and beyond, gradedresistive exercises are initiated.
SUMMARYIn the past several years, the extensor system has
received considerable attention as we have come tounderstand the complexity involved in extensor ten-don anatomy and appreciate the coordinated, com-plex interplay involved in upper extremity physiol-ogy. Until recently, extensor tendon injuries wereoften overlooked, with repairs being performed inemergency rooms, often by untrained professionals.The recent literature would support the notion thatthe extensor tendon system is challenging, with man-agement necessitating a thorough understanding ofboth anatomy and the relevant physiology.
Michael Saint-Cyr, M.D.Department of Plastic Surgery
University of Texas Southwestern Medical Center5323 Harry Hines Boulevard
ACKNOWLEDGMENTSThe authors thank Holly Smith and Margaret Wise,
who helped prepare this article. CPT codes commonlyused in extensor tendon surgery are listed in Table 1.
Fig. 12. Dynamic extension splint for extensor digitorum com-munis and extensor pollicis longus lacerations.
Fig. 13. Static extension splint for an extensor pollicis longuslaceration.
Table 1. CPT Codes Commonly Used in Extensor Tendon Surgery
CPTCode Descriptor
25270 Repair, tendon or muscle, extensor, forearm and/or wrist; primary, single, each tendon or muscle25272 Repair, tendon or muscle, extensor, forearm and/or wrist; secondary, single, each tendon or muscle25274 Repair, tendon or muscle, extensor, forearm and/or wrist; secondary, with free graft (includes obtaining
graft), each tendon or muscle26410 Repair, extensor tendon, hand, primary or secondary; without free graft, each tendon26412 Repair, extensor tendon, hand, primary or secondary; with free graft (includes obtaining graft), each tendon26418 Repair, extensor tendon, finger, primary or secondary; without free graft, each tendon26420 Repair, extensor tendon, finger, primary or secondary; with free graft (includes obtaining graft), each tendon26426 Repair of boutonniere; using local tissue, including lateral bands, each finger26428 Repair of boutonniere; with free graft (includes obtaining graft), each finger26433 Repair of extensor tendon, distal insertion, primary or secondary; without graft26434 Repair of extensor tendon, distal insertion, primary or secondary; with free graft (includes obtaining graft)
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REFERENCES1. Schneider, L. H. Hand Clinics: Extensor Tendon Injuries. Phil-
adelphia: Saunders, 1995.2. Green, D. P. Green’s Operative Hand Surgery, 5th Ed. Philadel-
phia: Elsevier Churchill Livingstone, 2005.3. von Schroeder, H. P., Botte, M. J., and Gellman, H. Anatomy
of the juncturae tendinum of the hand. J. Hand Surg. (Am.)15: 595, 1990.
4. Hirai, Y., Yoshida, K., Yamanaka, K., Inoue, A., Yamaki, K.,and Yoshizuka, M. An anatomic study of the extensortendons of the human hand. J. Hand Surg. (Am.) 26: 1009,2001.
5. von Schroeder, H. P., Botte, M. J., and Gellman, H. Anatomyof the juncturae tendinum of the hand. J. Hand Surg. (Am.)15: 595, 1990.
6. von Schroeder, H. P., and Botte, M. J. The functional sig-nificance of the long extensors and juncturae tendinum infinger extension. J. Hand Surg. (Am.) 18: 641, 1993.
7. Tubiana, R., and Valentin, P. The anatomy of the extensorapparatus of the fingers. Surg. Clin. North Am. 44: 897, 1964.
8. Schmidt, H. M., and Ulrich, L. Surgical Anatomy of the Hand.New York: Thieme, 2004.
9. Backhouse, K. M., and Catton, W. T. An experimental studyof the functions of the lumbrical muscles in the human hand.J. Anat. 88: 133, 1954.
10. Kaplan, E. B. Anatomy, injuries and treatment of the extensorapparatus of the hand and the digits. Clin. Orthop. 13: 24, 1959.
11. Gonzalez, M. H., Sohlberg, R., Brown, A., and Weinzweig, N.The first dorsal extensor compartment: An anatomic study.J. Hand Surg. (Am.) 20: 657, 1995.
12. Wood, V. E. The extensor carpi radialis intermedius tendon.J. Hand Surg. (Am.) 13: 242, 1988.
13. Schenck, R. Variations of the extensor tendons of the fingers:Variations and multiplicity. Surgical significance. J. Bone JointSurg. (Am.) 46: 103, 1964.
14. Gonzalez, M. H., Gray, T., Ortinau, E., and Weinzweig, N.The extensor tendons to the little finger: An anatomic study.J. Hand Surg. (Am.) 20: 844, 1995.
15. Kleinert, H. E., and Verdan, C. Report of the Committee onTendon Injuries (International Federation of Societies forSurgery of the Hand). J. Hand Surg. (Am.) 8: 794, 1993.
16. Abouna, J. M., and Brown, H. The treatment of mallet finger.Br. J. Surg. 55: 653, 1968.
17. Garberman, S. F., Diao, E., and Peimer, C. A. Mallet finger:Results of early versus delayed closed treatment. J. Hand Surg.(Am.) 19: 850, 1994.
18. Patel, M. R., Desai, S. S., and Bassini-Lipson, L. Conservativemanagement of chronic mallet finger. J. Hand Surg. (Am.) 11:570, 1986.
19. Newport, M. L., Blair, W. F., and Steyers, C. M. Long-termresults of extensor tendon repair. J. Hand Surg. (Am.) 15: 961,1990.
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