Hand and Wrist Surgery - part 6 ppsx

dis-Nonsurgical Management The concept of the “box” formed about the head of the proximal phalanx by thevolar plate and the accessory and true collateral ligaments of the PIP joint is us

PEARLS

• While the patient is under

digi-tal block at the time of

reduc-tion, assess the integrity of the

central slip insertion by

resis-tance to PIP flexion with the

MP joint flexed

• Begin motion as early as

pa-tient comfort will allow

• Assure a concentric reduction:

incarceration of the collateral

ligaments within the joint will

preclude their healing at an

Christopher H Martin and Steven Z Glickel

History and Clinical Presentation

A 43-year-old man caught his left small finger in the coat button of a coworker andthe digit was forcefully deviated ulnarward He felt a snap, and noticed an angulardeformity through the proximal interphalangeal (PIP) joint and an inability to fullyextend the finger

Diagnostic Studies

Radiographic evaluation in the emergency room showed a lateral dislocation of theproximal interphalangeal joint (Fig 46–1) Initial clinical examination showed sen-sory function to be intact on both sides of the digit, with brisk capillary refill Adigital block was placed and the dislocation was reduced with gentle longitudinaltraction Radiographic examination confirmed a concentric reduction of the PIPjoint with a symmetric joint space

Physical Examination

While still anesthetized, the finger was examined to assess stability of the joint andintegrity of the extensor system The patient was able to actively move the digitthrough a full range of motion There was no subluxation noted The integrity ofthe extensor mechanism and central slip insertion was then tested by having the pa-tient extend the PIP joint against examiner resistance with the metacarpophalangeal(MP) joint flexed There was full extension with normal strength compared with theuninjured digit

The digit was splinted with the PIP joint in full extension The patient was seenweekly for the next 2 weeks with radiographs confirming maintenance of the reduc-tion After 2 weeks, the digit was buddy taped to the adjacent ring finger and range

of motion was begun Due to some mild laxity in the healing radial collateral ment, the digit was buddy taped for a total of 4 weeks, after which a full, painlessrange of motion had been achieved

liga-Differential Diagnosis

Volar PIP rotary dislocationLateral PIP dislocationPIP joint fracture dislocationPIP joint sprain

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Figure 46–1 Posteroanterior (PA) radiograph of the small finger

shows a lateral dislocation of the proximal interphalangeal (PIP)

joint The proximal and middle phalanges are both in the same

plane, suggesting that there is not a major rotatory component to

the dislocation.

Radiographic examination of the laterally dislocated proximal interphalangeal joint

is sufficient to diagnose this injury Depending on the plane of the radiograph, ever, confusion between the true lateral dislocation and the volar rotatory dislo-cation is relatively common This distinction is important because the extensormechanism is disrupted in the volar rotatory dislocation as the head of the proximalphalanx protrudes through the triangular ligament between the lateral band andcentral slip The rotatory component of the volar dislocation can be suggested onplain x-rays if one view of the digit shows a true lateral of the proximal phalanx with

how-an oblique radiograph of the middle phalhow-anx (Fig 46–2) This chow-an help the tioner to distinguish between these injuries In the straight lateral dislocation, theextensor mechanism may or may not be injured

practi-Figure 46–2 Lateral and oblique radiographs of the injured digit show an incongruous PIP joint The proximal and middle phalanges are in nearly the same plane in the radiograph on the left, suggesting that this is a simple lateral dislocation.

Diagnosis

Lateral Dislocation of the PIP Joint

Lateral dislocations usually result from laterally directed or torsional forces acting on

an extended proximal interphalangeal joint The radial collateral ligament is injuredsix times more frequently than the ulnar collateral ligament True lateral dislocations

of the PIP joint are relatively rare when compared with dorsal and volar rotatory locations However, the patient himself or an athletic trainer prior to presentationprobably reduces some of these dislocations, like the more common dorsal disloca-tion The clinician must be wary of any significant injury to the PIP joint, as stiff-ness, pain, and limited use may supervene even with appropriate treatment Thesesymptoms may continue to improve after the injury, so education of the easily frus-trated patient is particularly important to optimize the result of treatment

dis-Nonsurgical Management

The concept of the “box” formed about the head of the proximal phalanx by thevolar plate and the accessory and true collateral ligaments of the PIP joint is usefulwhen considering the pathoanatomy of dislocations of this joint Lateral disloca-tions may occur after injury to the volar plate and at least one collateral ligament.Both collateral ligaments may also be ruptured

Biomechanical studies of the constraints about the PIP joint have demonstratedthat the collateral ligaments may fail at any point along their course, including anavulsion fracture from the phalanges The location of ligament failure is dependent

on the rate at which the lateral stress is applied Failure of the proximal portion ofthe ligament is most common After reduction and while under digital block anes-thesia, the degree of injury to the collateral ligaments may be assessed by the extent

to which the joint opens upon the application of lateral stress Opening over 20 grees is associated with a 100% chance of complete failure of the collateral ligament,whereas opening less than 20 degrees is associated with only a 53% chance of com-plete rupture Although this information is not useful in cases of documented dis-location, it may become useful in those instances in which the patient reports aninjury to the PIP joint that he or she has self-reduced

de-An intact lateral band will extend the PIP joint, and may mask an injury to thecentral slip Therefore, it is important to isolate the central slip when testing for in-juries to the extensor mechanism to whatever extent possible Flexion of the MPjoint places the lateral bands at a mechanical disadvantage, allowing preferential as-sessment of the integrity of the central tendon insertion Missed injuries of the cen-tral slip insertion may result in a boutonniere deformity, which is potentially one ofthe major pitfalls in the management of injuries to the PIP joint

Due to the bony architecture of the PIP joint, concentric reduction usually vides sufficient stability to allow for early motion within the limits of reasonablecomfort The arc through which the joint is stable should be assessed at the time

pro-of injury to avoid subluxation or redislocation This is best done when the joint isanesthetized, preferably with a digital block

Those factors that need to be considered in selecting the optimal position of jointimmobilization include the volar plate, the collateral ligaments, and the extensormechanism In lateral dislocations the volar plate is generally avulsed from thebase of the middle phalanx, so splinting in 20 to 30 degrees of flexion would seem

Im-be splinted in full extension to avoid the complication of a boutonniere formity Regardless of the position of immobilization, motion should be instituted

de-as early de-as possible The common complication of injuries to the PIP joint is ness, not laxity Volar plate and collateral ligament injuries can be mobilized as soon

stiff-as the patient is comfortable, providing the joint is stable Central tendon injuriesshould be protected longer, for about 3 weeks, and then mobilized, protecting theextensor mechanism with a dynamic extension splint

Surgical Management

Repair of the injured collateral ligaments and volar plate in the acute setting doesnot improve the outcome and may result in increased stiffness of the joint Acutesurgical intervention is reserved for cases of incongruent reductions, generally fromtissue interposed within the joint Stern has described a Stener-type lesion after lat-eral dislocation of the PIP joint in which the collateral ligament was incarceratedbetween the lateral band and the central slip, necessitating operative intervention.Although this lesion would seem more likely in volar rotatory dislocations, in whichthe triangular ligament between the lateral band and central slip is ruptured, it may

be seen in true lateral dislocations

Complications

Stiffness is a much more common sequela of injuries to the PIP joint than symptomatic joint laxity The surgical management of stiffness has included everything from

percutaneous release of the accessory collateral ligament to open complete excision

of the collateral ligaments Motion should be instituted as early as possible to avoidjoint stiffness

Laxity of the PIP joint is rare but can be very difficult to manage if it occurs The

re-sults of collateral ligament reconstruction are unpredictable and may have the lessthan desirable effect of exchanging the problem of laxity for that of stiffness Excision

of both ligaments in the lax joint, followed by early motion, may restore stability aseach ligament is allowed to reform in a more balanced situation

Suggested Readings

Bowers WH The proximal interphalangeal volar plate I: an anatomical and

biome-chanical study J Hand Surg [Am] 1980;5A:79–88.

Diao E, Eaton RG Total collateral ligament excision for contractures of the

proxi-mal interphalangeal joint J Hand Surg [Am] 1993;18A:393–402.

Eaton RG Joint Injuries of the Hand Springfield, IL: Charles C Thomas; 1971.

Kiefhaber TR, Stern PJ, Grood ES Lateral stability of the proximal interphalangeal

joint J Hand Surg [Am] 1986;11A:661–669.

Minamikawa Y, Horii E, Amadio PC, Cooney WP, Linscheid RL, An K-N Stability

and constraint of the proximal interphalangeal joint J Hand Surg [Am] 1993;18A:

198–204

Rhee RY, Reading G, Wray RC A biomechanical study of the collateral ligaments

of the proximal interphalangeal joint J Hand Surg [Am] 1992;17A:157–163.

Stanley JK, Jones WA, Lynch MC Percutaneous accessory collateral ligament

re-lease in the treatment of proximal interphalangeal joint flexion contracture J Hand

Surg [Br] 1986;11B:360–363.

Stern PJ Stener lesion after lateral dislocation of the proximal interphalangeal

joint-indication for open reduction J Hand Surg [Am] 1981;6A:602–604.

Dorsal Dislocations of the Proximal Interphalangeal Joint

Rosa L Dell’Oca and Amy Ladd

History and Clinical Presentation

A 40-year-old right hand dominant mechanic presented with a painfully swollenincongruent proximal interphalangeal (PIP) joint of his right index finger after atire exploded while he was increasing the air pressure Closed reduction, althoughsuccessful, resulted in an unstable joint

Physical Examination

The PIP joint demonstrated 15 degrees of ulnar deviation with considerable edemaand a volar laceration Tenderness was elicited over the volar and radial aspects ofthe joint Pain limited full active flexion, and the middle phalanx subluxed dorsally

at 10 degrees of active extension

Differential Diagnosis

Dorsal dislocation of the PIP jointLateral dislocation of the PIP jointVolar dislocation of the PIP jointFracture of the distal proximal phalanxFracture of the proximal middle phalanxSprain of the PIP joint

Lateral dislocation: greater than 20 degrees of angulation with ulnar/radial stress

of the PIP joint; radial or ulnar joint tenderness with or without volar plate derness; anteroposterior (AP) radiograph may demonstrate lateral displacement.Volar/lateral dislocation: lateral radiograph exhibits middle and distal phalanges

ten-at an oblique angle as compared with the proximal phalanx

Volar dislocation: tenderness of the dorsal aspect of the base middle phalanx; eral radiograph reveals a fracture of the dorsal aspect of the base of the middlephalanx

lat-Fractures: AP, lateral, and oblique (condyles) radiographs may display fractures ofthe head of the proximal phalanx or the base of the middle phalanx

Diagnosis

Dorsal Proximal Interphalangeal Joint Dislocation

Dorsal PIP dislocations are probably common but underreported, because manyhigh-paid athletes play with fresh injuries set in the field, or present with old un-treated injuries that may be painful, unstable, or fused Estimated at 9/100,000/year,the incidence of dorsal PIP fracture dislocations is much higher

History, physical examination, and radiographs reveal the diagnosis and nosis, and facilitate treatment History divulges the mechanism of injury and sug-gests the final configuration of the joint despite memory lapse or spontaneous ordeliberate reduction The joint may assume the characteristic bayonet configura-tion or an obvious posture of hyperextension but occasionally subtle subluxationrequires radiographic elucidation Palpation delineates the injured structures andactive range of motion may reveal instability with progressive extension Althoughpain and edema typically limit flexion, a torn volar plate interposed within the

Figure 47–1 Continued The full extent of the injury is appreciated best on lateral exam (C) and only after reduction (D), where the 50% involvement of the articular surface and the severely comminuted fragments may be appreciated.

PEARLS

• Obtaining perfect lateral

radi-ographs to detect the subtlest

incongruity

• Obtaining prompt attention by

hand specialist, or

knowledge-able practitioner and to not

ignore this common injury

PITFALL

• Disregarding the injury as a

simple sprain without

ade-quate physical and

radi-ographic examination

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joint must be considered If radiographic evaluation displays joint congruity, thensubtle instability may be elucidated by passive range of motion facilitated by adigital block

Stability on physical exam reflects the extent of injury to the primary (volar platecollateral ligament complex) and the secondary (flexor and extensor system) stabi-lizing forces, where certain sizes and configurations of fractures of the volar base ofthe middle phalanx compromise these forces Their vulnerability to hyperextension

or longitudinal loading defines their order and characteristic of injury

A simple sprain, recognized by a moderate amount of tenderness over the bruisedbut stable joint with a normal radiograph represents a partially torn ligament.Despite the check rein ligaments, proximal detachment of the volar plate occurs ex-perimentally with slow hyperextensile forces Conversely, longitudinal accelerated hy-perextensile forces cause distal rupture of the transversely oriented fibrocartilaginousfibers of the volar plate This injury alone allows greater than the normal 10 degrees

of hyperextension Typically, in these hyperextension injuries there is no history ofabnormal joint position, no evidence of instability on active and passive range ofmotion, and no articular incongruity or fracture on radiographs Even with an incom-plete longitudinal split in the collateral ligament, the remaining intact accessory col-lateral ligament imparts some stability

Higher energy forces produce tears between the thin accessory collateral ligamentand the thick primary collateral ligament in addition to volar plate disruptions Ex-periments suggest that partial volar plate tears represent areas of potential weakness

at risk of rupture with repeated stress Typically, these injuries present with a history

of joint misalignment and radiographs may demonstrate a small volar fragment.Part of the weak volar central trabecular base of the middle phalanx may remain at-tached to the volar plate, otherwise known as an avulsion injury Larger volar frag-ments typically result from greater longitudinal rather than hyperextensile forces,where the proximal phalanx shears off the volar base of the middle phalanx Smallervolar fragments (<30–50%) retain support from the remaining accessory collateralligaments and a portion of the primary collateral ligament (Eaton and Dray’s “stabledislocations”), whereas larger fragments portend relying solely on the extensor tendonand dorsal capsule for stability in flexion and have no support in extension, whichexplains the propensity to redislocate after reduction (Eaton and Dray’s “unstable dis-locations”) A direct correlation exists between the percent of volar middle phalanxsurface fractured and the likelihood of dorsal subluxation/dislocation Maximumcontact between the articular surfaces of this ginglymus joint, and the action of theflexor and extensor tendons pulling axially through a column consisting of the middlephalangeal base, resting on the proximal phalangeal condyles stabilized by the inter-digitation of the intercondylar sulcus and eminence, resist dislocation even in the face

of collateral ligament and volar plate disruption With intraarticular fractures, theresidual middle phalangeal dorsal articular surface and shaft form an inclined planethat tends to slide dorsally and proximally as the extensor and flexor tendons pullthe distal portion of the middle phalanx volarly and the proximal end of the middlephalanx dorsally, creating a zigzag posture Furthermore, the slightly different radii ofcurvature of the condyles allow some rotation despite the inherent lateral stability,which explains disproportionate injury to radial versus ulnar collateral ligaments.Classification systems with varying emphasis on the degree of ligamentous in-tegrity, the percentage of articular involvement, or the degree of subluxation exist tofacilitate the correct treatment The history of injury, the point and degree of insta-bility, and radiographic evaluation are adequate determinants in our opinion

Treatment

The injured athlete often reduces the dislocated finger If not, usually gentle tion will suffice to reduce the subluxated PIP joint Reduction of a true dislocationrequires reproduction of the original angle of injury to realign the joint surfaces andtraction on the middle phalanx with volarly directed pressure at its base Regionalblocks, muscle relaxants, finger-trap traction and arm-loaded countertraction fa-cilitate the difficult reductions, unless there is a hindering soft tissue entrapment.The ease of reduction is proportional to the quantity of intact ligament and in-versely proportional to the size of the fragment Fragments greater than 40% of thebase herald instability Joint congruity takes precedence over anatomic reduction

trac-of the fracture, for the subtlest incongruities may lead to chronic pain, degenerativechanges, and ankylosis The goal is stable, smooth, and pain-free range of motion ofthe affected joint This may be surprisingly difficult to attain

Nonoperative Management

After reduction or placement of the PIP joint at an acceptable angle without dence of subluxation, a period of rest is followed by protected active range of mo-tion For simple sprains, 1 to 3 weeks of splinting followed by a protected return tonormal activities within a few weeks with buddy taping, suffices

evi-An extension block splinting (EBS) regimen succeeds for hyperextension injuries, yet

some might buddy tape for 3 weeks or implement dorsal splinting for 7 to 14 dayswith an additional 2 weeks for residual volar instability followed by active andpassive range of motion Similar injuries, with radiographic evidence of minor sub-luxation that achieves congruity with manipulation fall into the same category butrequire hypervigilance with weekly radiographic confirmation of joint congruity forseveral weeks, followed by active and passive range of motion in a splint worn for anadditional 1 to 2 weeks

A known dislocation, demonstrating instability at less than 30 degrees of flexionwith or without a nondisplaced intraarticular fracture involving less than 50% of thevolar lip, may be treated successfully by closed reduction and EBS for 3 weeks, withactive range of motion commencing at 7 days followed by 3 weeks of buddy taping

Operative Intervention

Dislocations involving large volar fractures or those irreducible, unstable, or congruous joints, regardless of fracture size, require operative intervention In largedisruptions of the middle phalanx volar surface, without the stabilizing collateralligaments, the proximal phalangeal condyles sink into the volar plate and the dis-tal inserting flexor digitorum superficialis (FDS) and flexor digitorum profundus(FDP) bend the middle phalanx rather than produce gliding palmar rotation of thearticular base The joint fails to remain congruent and parallel with the proximalphalangeal head through flexion As a result, the joint hinges or angles For these ten-uous fractures, a transarticular Kirschner wire (K wire) may be placed through thePIP joint flexed at 40 degrees or more to diminish the subtle fracture articular siteincongruities associated with eventual failure and EBS initiated after K-wire removal

in-at 3 weeks Failure of closed reduction leaves open intervention or constant traction

as subsequent options Open reduction with internal fixation and EBS mobilization

at 3 weeks have been successful for tenuous fractures using such means as a single

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K wire with or without a tension band, an interfragmentary screw or an interosseouswire with the well-known complications of malunion, pin tract infection, tenodesis,and posttraumatic arthritis Other treatments include osteotomy with bone grafting,volar plate arthroplasty, secondary PIP arthroplasty, and arthrodesis

For fracture-dislocations involving greater than 70% of the volar lip, neitheradvancing the volar plate nor neocollateralization will successfully maintain reduc-tion Only reconstruction of a competent volar buttress restraint will prevent redis-location Yet attempts at realigning the large volar fragment by osteotomy and bonegrafting usually fail, requiring PIP joint salvage through replacement arthroplasty orarthrodesis In fact, regardless of the intervention(s), many ultimately end up with apain-free ankylosis or require silicone arthroplasty

For comminuted, impacted, and some irreducible fractures, treatment includesvolar plate arthroplasty, dynamic force coupling devices, and transarticular K-wireplacement Secondary options include custom external fixation or placement of aninterosseous wire through the volar plate to reduce the subluxed middle phalanxand mobilization with EBS Typically the comminuted fragments are too small forfixation and are debrided

In compound (open) dislocations involving a volar transverse tear in the skinwith occasional protrusion of the head of proximal phalanx through skin and/orflexor tendon involvement, Stern and Lee found that the joint could not be stablyreduced if the volar plate was not repaired distally, whereas Green and Posner foundthat it was not necessary with proximal tears

Acutely treated injuries enjoy better outcomes than those that present late, that is,greater than 4 weeks after the injury Injuries limited to volar plate avulsion withflexion deformity less than 30 degrees allow late primary repair, which may decreasethe chance of severe flexion contractures

For a subacute, greater than 10 days postincident, volar plate injury with eral ligament injuries and persistent subluxation, restoration of range of motionmay require excision of the contracted and normal primary and accessory collateralligaments and dorsal capsule with immediate active range of motion, for excision ofonly the contracted ligaments will not restore full range of motion Sparing part ofthe accessory collateral ligaments affords some stability

collat-Delayed treatment of large fractures requires release of the collateral ligaments toallow fragment reduction and possibly additional volar plate arthroplasty for com-minuted fragments Osteotomy of the proximal middle phalanx may provide an ad-ditional 40 degrees range of motion as the volar lip of the middle phalanx tilts toembrace the volar proximal phalanx

For severe articular damage, failed reconstruction, persistent deformity, and pain,salvage procedures may be necessary Arthrodesis in the radial digits to stabilizepinch, and replacement arthroplasty for the little and ring fingers to allow powergrasp, may provide significant improvement in function and appearance

Extension Block Splinting

Based on early range of motion within a stable arc, this straightforward, easily tuted and monitored method requires readily available and inexpensive materialsand enjoys great success for stably reduced dislocations or as a means of protected

insti-range of motion after an open procedure Although indicated for stable fractures of less

than 10 to 15% involvement of the volar base, fractures constituting <40% of the base are still considered in the ideal group, and success has been found with some fractures

as great as 70% Once adequately reduced, a digital, hand, or forearm-based splint

ensures that the digit remains well opposed to the splint and maintains flexion ofthe PIP joint blocked at 10 to 20 degrees greater than the point of demonstrable in-stability Although McElfresh et al allowed up to 60 degrees of flexion to obtain sta-bility, most accept a maximum of 30 degrees This guideline prevents the chance ofirreversible flexion contracture and delegates cases requiring greater than 30 degrees

to other treatments Lateral radiographs within the splint confirm this optimalpoint of flexion where the articular surfaces are absolutely congruent, for the PIPjoint may become incongruous slowly, gradually, and subtly with extension Someembark on immediate active range of motion, whereas others allow 1 week of rest.After 1 week of mobilization and radiographic and clinical confirmation of sus-tained congruity at rest and in maximum flexion, the degree of flexion is reduced byone third and the joint reassessed by a lateral radiograph If radiographs demon-strate incongruity, extension is increased by only one half of the potential extension.After the usual interval to full extension (6–8 weeks), the splint is removed and gripand massage exercises are started, but pinch to the involved finger and stretching ofthe involved joint is avoided until grip strength is 50% Full rehabilitation is com-plete by the third month postinjury

Conversion to other forms of treatment is straightforward without delay in the all process Complications, such as flexion contractures are rare and salvageable Afterthe appropriate period of treatment has ended, for flexion contractures less than 10 de-grees, a trial of active use equal to the period of splinting is usually sufficient and forcontractures greater than 10 to 15 degrees, dynamic extension splinting is warranted

over-Open Reduction and Internal Fixation

Eaton and Malerich describe an elegant volar radial, rather than dorsal, approach

to preserve the skin flaps should open reduction prove futile and be abandoned for

a volar plate arthroplasty After excising the sheath between the A2 and A4 leys, the volar plate is detached distally from the middle phalangeal fragments andlaterally from the accessory collateral ligaments to open and shotgun the floor of thejoint Drilling a hole distal to the fracture allows introduction of a probe to elevateand reduce the fragments Whichever method of fixation is used, the hardwareshould exit close to the central slip insertion without tenting the dorsal skin or pen-etrating the lateral bands or retinacular structures Once the fracture is stabilized,extension block splinting may be instituted as above

pul-Volar Plate Arthroplasty (VPA)

Introduced by Eaton in 1967, VPA finds application in the following: acute dislocations displaying volar proximal middle phalangeal fractures of greater than60% or those with excessive comminution and/or impaction; and chronic fracture-subluxation of the PIP, where there are degenerative changes or joint stiffness.Utilizing the volar radial approach described above, the crucial step relies on cre-ating a symmetric trough in the volar base of the middle phalanx to allow the volarplate to slip easily into the defect Asymmetry usually prevents successful fracturereduction Introducing a pullout wire Kessler style allows the ends to exit the distalcorners of the volar plate and secure it to the radial and ulnar aspects of the middlephalanx through holes drilled laterally into the trough The author (A.L.) employstissue anchors, an updated version of this technique Securing the wires to produce

fracture-no more than 30 degrees of flexion reduces and stabilizes the joint, fills the volar fect, and decreases lateral angular deviation By flexing the PIP and DIP joints while

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Figure 47–2 Dynamic force coupling device The axis of rotation of the proxi- mal interphalangeal (PIP) joint is equidistant from the distal dorsal and palmar ar- ticular surfaces at the origin

of the primary collateral ligament.

passing the pullout sutures dorsally, the lateral bands subluxate volarly, avoid trapment, and thus lessen DIP stiffness Embedded fragments of bone or cartilagecan be left in place A transarticular K wire is placed for joint stability and for verylarge disruptions (50–80%); an external fixator may be required for ~1 to 2 weeks.After K-wire removal at 2 weeks, EBS commences and the pullout wire is removed

en-1 week later, with unrestricted extension beginning at 4 weeks

Complications include redislocation with an inadequately secured K wire, gular deformity with an undercorrected asymmetric trough or inadequate medial-lateral reduction, and flexion contracture after 6 weeks with immobilization inexcessive flexion or inadequate collateral ligament release

an-Aside from acutely reducing the dislocated joint, VPA maintains congruous PIPjoint reduction by providing a volar restraint, resurfaces the damaged articular sur-face of the middle phalanx with compatible vascularized material, fibrocartilage, andmay be responsible for later joint remodeling and continuously improving range

of motion even years later

Dynamic Force Coupling

Robertson et al corrected the zigzag deformity by placing K wires to apply tractiondorsally on the distal proximal phalanx and volarly on the proximal middle phalanx

to realign the joint and axially on the distal middle phalanx to counteract flexorand extensor pull Beasley used a static, bulky device incorporating distal tractionwith a volar splint to push the distal proximal phalanx dorsally By decreasing thesize of the device and allowing movement during traction, Agee enjoyed better re-sults compared with Robertson et al and equaled those of McElfresh et al for acutefracture-dislocations and chronic fracture-dislocations

Implementation requires an adequate stable dorsal shelf of proximal middlephalangeal bone and careful K-wire placement (Fig 47–2) The K wire placedtransversely in the proximal middle phalanx must be a safe distance away fromthe fracture and volar to the lateral bands The K wire oriented perpendicular tothe middle phalanx should not be driven too far distally through the lateralbands, preventing motion of the distal phalanx, or too deeply through the pro-fundus tendon Lastly, the transverse K wire through the proximal phalanx must

be exactly through the axis of rotation to prevent hyperextension and possible

swan neck deformity Often subacute unstable cases greater than 10 days injury cannot be reduced in a closed fashion, and require release of the malposi-tioned collateral ligaments

post-Chronic Problems/Complications

Accurate diagnosis and prompt treatment are paramount in minimizing prolonged stability, chronic subluxation/dislocation, degenerative arthritis, stiffness, and pain

in-It is important to note that a minimum of 8 to 18 months may be required for edema

to subside to the point of maximum improvement, where residual permanent jointenlargement is due to scar tissue Despite adequate treatment, complications mayoccur, such as extension and flexion contractures, and swan neck and pseudobouton-niere deformities

In general, most PIP dislocations may be treated by EBS, leaving the operativetechniques for the more difficult fracture dislocations

Suggested Readings

Agee JM Unstable fracture dislocations of the proximal interphalangeal joint

Treatment with the force couple splint Clin Orthop 1987;214:101–112.

Beasley RW Hand Injuries Philadelphia: WB Saunders; 1981:165.

Bowers WH The proximal interphalangeal joint volar plate II: a clinical study of

hyperextension injury J Hand Surg [Am] 1981;6:77–81.

Bowers WH, Wolf JW Jr, Nehil JL, Bittinger S The proximal interphalangeal joint

volarplate I An anatomical and biomechanical study J Hand Surg [Am] 1980;5:

79–88

Buchanan RT Mechanical requirements for application and modification of the

dynamic force couple method Hand Clin 1994;10:221–228.

Donaldson WR Chronic fracture-subluxation of the proximal interphalangeal joint

J Hand Surg [Am] 1978;3:149–153.

Dray GJ, Eaton RG In: Green D, ed Operative Hand Surgery, 2nd ed New York:

Eaton RG, Malerich MM Volar plate arthroplasty of the proximal

interpha-langeal joint: A review of ten years’ experience J Hand Surg [Am] 1980;5:260–

268

Green SM, Posner MA Irreducible dorsal dislocations of the proximal

interpha-langeal joint J Hand Surg [Am] 1985;10:85–87.

Hamer DW, Quinton DN Dorsal fracture subluxation of the proximal

interpha-langeal joints treated by extension block splintage J Hand Surg [Br] 1992;17:586–

590

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Hastings H II, Carroll C IV Treatment of closed articular fractures of the

meta-carpophalangeal and proximal interphalangeal joints Hand Clin 1988;4:513–

McElfresh EC, Dobyns JH, O’Brien ET Management of fracture-dislocation of the

proximal interphalangeal joints by extension-block splinting J Bone Joint Surg

[Am] 1972;54:1705–1711.

Robertson RC, Cawley JJ Jr, Faris AM Treatment of fracture-dislocation of the

interphalangeal joints of the hand J Bone Joint Surg 1946;28:68–70.

Stern PJ, Lee AF Open dorsal dislocations of the proximal interphalangeal joint

J Hand Surg [Am] 1985;10:364–370.

Swanson AB, Maupin BK, Gajjar NV, de Groot Swanson G Flexible implant

arthroplasty in the proximal interphalangeal joint of the hand J Hand Surg [Am]

1985;10A:796–805

Zemel NP, Stark HH, Ashworth CR, Boyes JH Chronic fracture dislocation of the

proximal interphalangeal joint–Treatment by osteotomy and bone graft J Hand Surg

[Am] 1981;6:447–455.

PEARLS

• In a spontaneously reduced

dis-location with an open wound,

the joint must be explored and

irrigated thoroughly.

PITFALLS

• Avoid chronic deformity and

disability by testing active

ex-tension and flexion of the DIP

joint after reduction

Figure 48–1 Lateral ograph after reduction at- tempt with persistent dorsal dislocation of distal inter- phalangeal (DIP) joint.

radi-48

Distal Interphalangeal Joint Dislocations

John D Wyrick

History and Clinical Presentation

A 24-year-old right hand dominant man injured his right small finger while playingsoftball The ball struck him on the tip of the finger and he thought he “onlyjammed” the finger He describes pulling on the finger, which made it feel a littlebetter, but always noted some deformity, which he attributed to swelling He didnot seek medical attention until 10 days after the injury When seen, he describedpersistent pain and lack of motion as the main reasons for seeking help

Physical Examination

Significant swelling diffusely throughout the right small finger is noted It is moreprominent distal to the proximal interphalangeal (PIP) joint No wounds were pre-sent Grossly, there was a prominence dorsally at the distal interphalangeal (DIP)joint and obvious deformity Due to pain his passive motion was not tested, but hisactive motion was 10 to 25 degrees Sensibility testing revealed static two-point dis-crimination of 5 mm

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Mallet injury

Avulsion of flexor digitorum profundus (FDP) tendon

PIP joint dislocation

Diagnosis

Dislocation of the DIP Joint

Dislocations of the DIP joint are not commonly seen More common is the dorsal PIPjoint dislocation, which is the result of a hyperextension injury Often these DIP jointinjuries are reduced in the field and are never seen for medical attention

Most commonly the DIP dislocations are in the dorsal direction following perextension injuries The joint is inherently quite stable because of the strong at-tachments of the two collateral ligaments and volar plate, which create a box-likeconfinement The flexor and extensor tendons as well as the tight skin add furtherstability The skin is so taut in this region that these injuries are often open with apalmar wound If this is the case, the wound needs to be explored under adequateanesthesia to be certain there is no contamination in the joint, and to irrigate it well.The diagnosis is usually straightforward The major considerations in the differen-tial diagnosis are various fractures around the DIP joint These can easily be excluded

hy-by routine anteroposterior (AP) and lateral radiographs both before and after tion Once reduction is obtained, it is very important to test the integrity of the ex-tensor and flexor digitorum profundus (FDP) tendons, as either can be injured withthe dislocation If missed, these injuries can be extremely difficult to treat later

reduc-Nonsurgical Management

It is extremely uncommon for these injuries to require surgery After obtaining theappropriate radiographs and the diagnosis is made, the next step is administering ananesthetic Lidocaine 1% without epinephrine is injected as a metacarpal block to anes-thetize the radial and ulnar digital nerves and then injected dorsally subcutaneous atthe base of the finger to block the dorsal sensory nerves Usually only ~4 to 5 cc arerequired Once the patient is anesthetized, the reduction can usually be obtained withlongitudinal traction and flexion of the DIP joint for dorsal dislocations Sometimes anexaggeration of injury (e.g., hyperextension of the joint) may be necessary to reduce it.For the volarly displaced injuries, traction and extension are used for reduction.Once the reduction is completed, the joint is first tested for stability, both passivelyand actively Most important is to actively test the extension and flexion of the DIPjoint An extensor lag can be indicative of a mallet injury and needs to be splinted ap-propriately (see Case 38, Mallet Fractures) A mallet injury would be more likely with avolar dislocation If the patient cannot actively flex the DIP joint, he or she may have

an FDP avulsion, which needs urgent treatment like any flexor tendon injury

After stability testing, AP and lateral radiographs need to be obtained (1) to firm a concentric reduction and (2) to make sure no fractures have been missed.These injuries are rarely unstable and thus need no splinting If the patient is un-comfortable, then a removable splint can be applied for approximately 1 week Ifthere is instability, a splint should be fashioned to keep the joint in slight flexion.This should not be necessary for more than 3 weeks

con-In the case presented here, attempted reduction under metacarpal block was cessful After a reduction attempt and splinting, radiographs appeared as in Figure 48–1

Surgical Management

In the unlikely event that the joint cannot be reduced, as in the case presentedhere, surgery is necessary to remove the structure blocking reduction This is mostoften due to the interposed volar plate, which is still attached to the distal phalanx.Other reported causes include entrapment of the FDP tendon, buttonholing thevolar plate, and osteochondral fractures

The surgery can be performed under metacarpal block as described above A sal H or Y incision is centered over the DIP joint (Fig 48–2) The extensor tendon

dor-is retracted and the volar plate can be teased back over the head of the middle lanx with a Freer elevator

pha-Joint stability is then tested as described above, and because the patient is awake andunder a digital block, he can demonstrate active and passive motion Radiographs arelikewise obtained

In the case presented, the joint was explored as described and the volar platewas blocking the reduction Once the joint was reduced, however, it still had a ten-dency to sublux Therefore, a 0.035-inch Kirschner wire (K wire) was placed acrossthe joint with the joint in extension (Fig 48–3)

Extensor tendon

Extensor tendon P1 P2

P2 P3

P3 Volar plate

Volar plate Incision

Figure 48–3 Lateral ograph after open reduction and pinning of DIP joint.

radi-A

B

Figure 48–2 Surgical proach for open reduction of DIP joint (A) Lateral view (B) Incision (C) Dorsal view

ap-of dislocation with volar plate blocking reduction.

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Postoperatively, the K wire was removed at 3 weeks and active and passive motionwas started It is important to have the patient moving the metacarpophalangeal(MP) and PIP joints during the time the DIP joint is immobilized

Complications

Complications from this injury are rare Stiffness can be a problem, but becausethese joints are typically stable after reduction, range of motion can be started im-mediately The other concern is missed accompanying injuries, which can be ruledout with active motion testing and appropriate radiographs

Suggested Readings

Bayne O, Chabot JM, Carr JP, Evans EF Simultaneous dorsal dislocation of

inter-phalangeal joints in a finger Clin Orthop 1990;257:104–106.

Green DP, Hotchkiss RN, Pederson WC Green’s Operative Hand Surgery 4th ed.

Philadelphia: Churchill Livingstone; 1998

Inoue G, Maeda N Irreducible palmar dislocation of the distal interphalangeal

joint of the finger J Hand Surg [Am] 1987;12A:1077–1079.

Palmer AK, Linscheid RL Irreducible dorsal dislocation of the distal

interpha-langeal joint of the finger J Hand Surg [Am] 1977;2:406–408.

Stripling WD Displaced intra-articular osteochondral fracture—cause for irreducible

dislocation of the distal interphalangeal joint J Hand Surg [Am] 1982;7:77–78.

Zielinski CJ Irreducible fracture-dislocation of the distal interphalangeal joint: a

case report J Bone Joint Surg [Am] 1983;65:109–110.

PEARLS

• Radiographic signs of a

com-plex dislocation:

䡩 Widened MP joint space:

interposed volar plate

䡩 Sesamoid in MP joint space

䡩 Dorsal dislocation with slight

hyperextension

• Avoid digital nerve injury by

using caution on the volar skin

incision or using the dorsal

incision

• Prevent misdiagnosis or

de-layed diagnosis by prompt

ra-diographic examination after

injury

PITFALLS

• Traction or hyperextension

dur-ing attempted closed

reduc-tion can convert a reducible

dislocation into a complex one

• Prolonged postoperative

im-mobilization leads to stiff joints

49

Dorsal Metacarpophalangeal Dislocations (Irreducible)

Benjamin Chang and Mark Katz

History and Clinical Presentation

A 12-year-old boy was playing football and caught the ball on the end of his indexfinger He noted immediate pain and deformity at the base of the finger and wasunable to move the finger He was brought to the emergency department on thesame day for treatment

Physical Examination

The patient’s index finger was slightly hyperextended at the metacarpophalangeal(MP) joint and flexed at the proximal interphalangeal (PIP) joint There was noactive motion at either joint The skin was intact The index metacarpal head wasprominently palpable in the palm Sensibility and capillary refill were normal Theremainder of the upper extremity was nontender

Radiographic Findings

Radiographs of the hand revealed slight distraction at the MP joint and ulnar deviation

of the index finger on the posteroanterior view (Fig 49–1) The lateral view clearlydemonstrates the dorsal dislocation and widened MP joint space caused by interposedsoft tissue (Fig 49–2) An oblique view was also obtained No fractures were seen

Differential Diagnosis

Sprain of the MP jointFracture of the distal metacarpalFracture of the proximal phalanxDislocation

Reducible MP jointIrreducible MP joint

Diagnosis

Complex Dorsal Metacarpalphalangeal Dislocation

Widening of the MP joint and mild hyperextension favor a complex dorsal cation of the MP joint The differential diagnosis includes subluxation of the MPjoint, but the joint is usually hyperextended at 60 to 80 degrees with subluxation.Dorsal dislocation of the MP joint usually results from a hyperextension injury.The index and small fingers are the most commonly involved digits It is important

Figure 49–1 Posteroanterior radiograph of a complex dor- sal dislocation of the index metacarpophalangeal joint.

Note the ulnar deviation

Figure 49–2 Lateral radiograph of a complex dorsal dislocation of the index metacarpophalangeal joint Note

the widened joint space, dorsal displacement, andhyperextension

to differentiate between subluxation and simple dislocation, which can be reduced

by closed manipulation, and complex dislocation, which requires open reduction.Subluxation produces a greater dorsal angulation and should be reduced by apply-ing pressure to the dorsal base of the proximal phalanx without longitudinal trac-tion or forced hyperextension to re-create the mechanism of injury A subluxationcan be converted to a complex dislocation if improperly manipulated

A complex dislocation typically presents with dorsal displacement and slight perextension of the proximal phalanx relative to the metacarpal The interphalangealjoints are slightly flexed In the index finger, the proximal phalanx is usually deviatedtoward the long finger The metacarpal head is prominent in the palm, and carefulinspection may reveal the pathognomonic skin pucker at the proximal palmar crease.However, swelling may obscure these findings; therefore, radiographs are essential forconfirming the diagnosis and excluding associated fractures

hy-The volar plate is the key structure blocking reduction in complex dislocations.Hyperextension of the MP joint avulses the volar plate from the weaker proximal at-tachment to the metacarpal neck and displaces it over the dorsum of the metacarpalhead The deep transverse metacarpal ligament is partially torn at its attachment

to the side of the volar plate In the case of the index finger, the metacarpal headbecomes trapped by the volar plate dorsally, the lumbrical radially, and the flexortendons ulnarly Longitudinal traction tightens the flexor tendon and lumbrical,creating a “noose” around the metacarpal head, thus the recommendation thatclosed reduction be performed with the wrist flexed to relax the flexor tendon andlumbrical Even with the wrist flexed, the collateral ligaments may prevent adequatedistraction of the joint to allow for escape of the volar plate and reduction of thejoint Therefore, the key to open reduction is division of the proximal portion of thevolar plate to allow the metacarpal head to slide through

Surgical Management

Closed reduction under intravenous sedation was attempted in the emergency partment by flexing the wrist and applying pressure to the dorsal base of the indexproximal phalanx No change in alignment was achieved The patient was taken tothe operating room for open reduction on the same day

de-Open reduction was performed under general anesthesia through a dorsal proach Surgical exposure was gained through an ulnarly based triangular flap overthe dorsal aspect of the index MP joint The ulnar sagittal band was incised and theextensor tendon retracted radially The dorsal joint capsule was incised longitudi-nally to expose the joint There was a 5 ⫻ 6 mm chondral fragment attached by softtissues to the dorsal aspect of the metacarpal neck (Fig 49–3) The fragment wasreflected proximally, revealing the base of the proximal phalanx with the volar plateattached and interposed over the metacarpal head The proximal portion of thevolar plate was incised longitudinally in the midline The proximal phalanx wasthen easily reduced with pressure over the dorsal aspect of the base The MP jointremained reduced from 0 to 90 degrees of flexion and there was no laxity of thecollateral ligaments with the joint flexed

ap-The chondral fragment was reduced and stabilized by closing the dorsal joint sule The ulnar sagittal band was repaired The skin was closed in layers with buriedsubcuticular sutures The hand was immobilized in a volar splint with the MP joints

cap-in 60 degrees of flexion and the cap-interphalangeal jocap-ints extended

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Figure 49–3 Dorsal view

of the index langeal joint, showing the chondral fracture fragment.

metacarpopha-Postoperative Management

Because of the chondral fracture, immobilization in the splint was maintained for

1 week Active range of motion was then begun with buddy taping to the long ger Full active extension and flexion were achieved by 8 weeks

fin-Alternative Methods of Management

Alternatives include a longitudinal incision through the extensor tendon or avolar approach The tendon-splitting approach is advocated by some to allow forearlier motion This is a valid argument, although we have not had any extensortendon subluxation from sagittal band rupture with only 1 week of postoperativeimmobilization

A volar approach can be used for open reduction of a complex dorsal MP cation For the index finger, the skin is incised at the thenar crease over the indexmetacarpal The radial digital neurovascular bundle is usually tented up by themetacarpal head and is easily injured The structures surrounding the metacarpalhead are then serially divided starting with a longitudinal incision through thevolar plate Because the volar plate is trapped dorsal to the metacarpal head, divid-ing the proximal margin may be difficult Next, the natatory ligament is dividedfollowed by the superficial transverse metacarpal ligament The primary argumentfor using the volar approach is that division of these volar structures is necessary

frac-frequently on the dorsal aspect of the metacarpal head One disadvantage of the

dorsal approach is the need to go through the extensor mechanism to expose the joint.

Complications

Complications include stiffness, degenerative arthritis, digital nerve damage, andmisdiagnosis resulting in delayed treatment Stiffness is best prevented by early mo-tion Use extension block splinting to allow for early motion if there is instabilityafter reduction If the joint is stable, buddy taping is sufficient

Degenerative arthritis may arise from articular damage as a result of the injury orthe reduction Avoid multiple attempts at closed reduction During open reduction,make an adequate incision in the volar plate to allow for easy reduction Inspect thearticular surfaces for osteochondral fractures, which may not show up on the radi-ograph, and treat them

Suggested Readings

Becton JL, Christian JD, Goodwin HN, Jackson JG A simplified technique for

treating the complex dislocation of the index metacarpophalangeal joint J Bone

Joint Surg [Am] 1975;57A:698–700.

Green DP, Terry GC Complex dislocation of the metacarpophalangeal joint

Cor-relative pathological anatomy J Bone Joint Surg [Am] 1973;55A:1480–1486 Inoue G, Miura T Locked metacarpophalangeal joint of the finger Orthop Rev

1991;20:149–153

Kaplan EB Dorsal dislocation of the metacarpophalangeal joint of the index finger

J Bone Joint Surg [Am] 1957;39A:1081–1086.

May JW Jr, Rohrich RJ, Sheppard JS Closed complex dorsal dislocation of themiddle finger metacarpophalangeal joint: Anatomic considerations and treatment

Plast Reconstr Surg 1988;82:690–693.

Nussbaum R, Sadler AH An isolated, closed, complex dislocation of the

metacar-pophalangeal joint of the long finger: a unique case J Hand Surg [Am] 1986;11A:

558–561

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PEARLS

• If the mechanism is a

hyper-extension, then think an injury

to the distal volar plate

avul-sion and plan a volar surgical

approach

• If the mechanism is a

hyper-flexion, then suspect a proximal

dorsal capsule interposition

and plan a dorsal surgical

approach

PITFALLS

• The digital nerves are displaced

by the dislocation and are

more prone to iatrogenic injury

from the volar incision.

• Prolonged postoperative

im-mobilization in the absence of

a fracture is unnecessary and

leads to stiff joints

50

Volar Metacarpophalangeal Dislocations (Irreducible)

Benjamin Chang and Mark Katz

History and Clinical Presentation

A 17-year-old boy was grabbed by the left ring finger during an altercation and thefinger was twisted He noted immediate pain, swelling, and deviation of the finger

He came to the emergency department on the same day for treatment

Physical Examination

The patient’s ring finger was ulnarly angulated, shortened, slightly hyperextended at themetacarpophalangeal (MP) joint, and flexed at the proximal interphalangeal (PIP) joint.There was no active motion at either joint The skin was intact The base of the proximalphalanx was prominently palpable in the palm and deviated to the radial side Sensibilityand capillary refill were normal The remainder of the upper extremity was nontender

Differential Diagnosis

DislocationVolar MP jointSimpleComplexDorsal MP jointSimpleComplexSprain of the MP jointFracture of the distal metacarpalFracture of the proximal phalanx

Diagnostic Studies

Radiographs of the hand revealed a fracture/dislocation of the MP joint with ulnardeviation of the ring finger and radial displacement of the base of the proximal pha-lanx on the posteroanterior view (Fig 50–1) The lateral view clearly demonstratesthe volar dislocation of the proximal phalanx relative to the metacarpal head (Fig.50–2) An oblique view was also obtained

Diagnosis

Volar Intraarticular Fracture/Dislocation of the Ring Finger MP Joint

The radial collateral ligament is presumably still attached to the small fracture ment, but the ulnar collateral ligament must be completely disrupted to permit thisdegree of displacement

Figure 50–2 Lateral ograph of a complex volar fracture-dislocation of the left ring finger metacarpopha- langeal joint.

radi-rior radiograph of a complex volar fracture-dislocation of the left ring finger metacar- pophalangeal joint.

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Volar dislocation of the MP joint is very rare and can arise from both sion and hyperflexion injuries Successful closed reduction has been reported andshould be attempted after radiographic confirmation of the diagnosis

hyperexten-The volar plate can be avulsed from the base of the proximal phalanx by extension and become interposed in the MP joint, as in this case, trapping theproximal phalanx between the flexor tendons and the lumbrical One may expectthe more common dorsal dislocation with hyperextension, but Betz et al suggestedthat volar dislocation is produced when hyperextension force is applied to an ac-tively flexing finger

hyper-The dorsal joint capsule can be avulsed proximally from the metacarpal by perflexion and become interposed in the joint, thus blocking reduction Wood andDobyns have reproduced this injury in cadavers with hyperflexion and proximaltranslation Hyperflexion force applied to the dorsum of the thumb proximal pha-lanx produces a tear of the dorsal capsule and herniation of the metacarpal headthrough the extensor aponeurosis between the extensor pollicis longus on the ulnarside and the extensor pollicis brevis on the radial side The extensor aponeurosis isthen trapped volar to the metacarpal head, preventing its reduction

hy-Surgical Management

Closed reduction under general anesthesia was attempted in the operating room

on the day of injury but was unsuccessful Open reduction was performed through

a volar zigzag incision over the ring finger metacarpal extending up to the PIP ion crease The digital neurovascular bundles were identified and retracted Thebase of the proximal phalanx was found to be displaced volar and radial to theflexor tendons There was an articular fragment missing from the radial base ofthe proximal phalanx (Fig 50–3) The volar plate and collateral ligaments were

flex-no longer attached to the proximal phalanx, but were found dorsal to the mal phalanx The base of the proximal phalanx was trapped between the flexor ten-dons on the ulnar side, the lumbrical on the radial side, and the volar plate on thedorsal side

proxi-The A1 pulley was incised and the flexor tendons returned to their normal tion volar to the proximal phalanx The base of the phalanx was then easily reduced

posi-An interosseous wire was placed through drill holes to secure the fracture fragment

to the base of the phalanx, restoring anatomic alignment (Fig 50–4) The volarplate was reattached to the proximal phalanx with 4–0 Prolene passed through theperiosteum and flexor tendon sheath at the lateral edges of the A2 pulley After re-duction and repair, the MP joint was stable through a passive range of motion be-tween 0 and 90 degrees of flexion

After skin closure, a short arm cast was applied with the wrist in slight extension,the MP joints in flexion and the PIP joints fully extended

Postoperative Management

The cast remained in place for 3 weeks Gentle active range of motion commenced

at 3 weeks The patient began passive range of motion, blocking, and strengthening

at 6 weeks At 3 months, the patient had full active motion at the interphalangealjoints and -15/80 degrees at the MP joint of the ring finger

Figure 50–4 Posteroanterior radiograph of the ring finger metacarpophalangeal joint after anatomic reduction of the fracture-dislocation.

of the left ring finger mal phalanx showing the ar- ticular fracture at the base.

proxi-V O L A R M E T A C A R P O P H A L A N G E A L D I S L O C A T I O N S ( I R R E D U C I B L E )

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Alternative Methods of Management

The volar approach is preferred for open reduction of a complex volar MP dislocation produced by hyperextension This approach allows for removal of the volar plate from

the joint and reattachment to the proximal phalanx, but carries a risk of cular injury

neurovas-The dorsal approach is preferred for volar MP dislocation produced by hyperflexion.

This approach allows for extraction of the dorsal capsule (or the extensor aponeurosis

in the thumb) from the MP joint When the mechanism of injury is not clear, onemay need to make both volar and dorsal incisions to achieve reduction

In the case of a chronic volar dislocation, open reduction should be attempted,even several months after injury If gross degenerative joint changes are present, im-plant arthroplasty or arthrodesis is a reasonable alternative

Complications

Complications include stiffness, degenerative arthritis, digital nerve damage, and

misdiagnosis resulting in delayed treatment Stiffness is best prevented by early tion If the joint is stable after reduction and there is no fracture, prompt mobiliza-tion with active range of motion is permitted

mo-Degenerative arthritis may arise from articular damage as a result of the injury orthe reduction Avoid multiple attempts at closed reduction During open reduction,perform adequate soft tissue releases to permit reduction without “prying” the jointinto place

Avoid digital nerve injury by using caution on the volar skin incision Preventmisdiagnosis or delayed diagnosis by prompt radiographic examination after injury

Suggested Readings

Betz RR, Browne EZ, Perry GB, Resnick EJ The complex volar

metacarpopha-langeal joint dislocation A case report and review of the literature J Bone Joint Surg

[Am] 1982;64A:1374–1375.

Gunther SF, Zielinski CJ Irreducible palmar dislocation of the proximal phalanx of

the thumb—case report J Hand Surg [Am] 1982;7A:515–517.

Perez-Aguilar D, Sendino M, Domenech J, del Campo M Palmar dislocation of the

metacarpophalangeal joint of the thumb: a case report J Hand Surg [Am] 1996;

21A:687–688

Renshaw TS, Louis DS Complex volar dislocation of the metacarpophalangeal joint:

a case report J Trauma 1973;13:1086–1088.

Wood MB, Dobyns JH Chronic complex volar dislocation of the

metacarpopha-langeal joint: report of three cases J Hand Surg [Am] 1981;6:73–76.

History and Clinical Presentation

A 24-year-old left hand dominant woman presents with a swollen and painful leftthumb While skiing the patient felt a sharp pain in her thumb at the metacar-pophalangeal (MP) joint when she put her hand out to stop her fall She recalls herthumb landed in an outstretched fashion in the snow and was pulled backward andout of the palm She is unable to use her thumb secondary to pain She denies anyprevious history of trauma to her hand or thumb

Physical Examination

The patient demonstrated tenderness along the ulnar collateral ligament (UCL)

of the MP joint of the thumb She has localized swelling and ecchymosis Stress