New Malunion Background

7/23/2019 New Malunion Background

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BackgroundMalunion may be defined as healing of a fracture in an abnormal (nonanatomic) position. In the hand,it presents a combination of a functional problem with an aesthetic problem. The management ofmalunion of hand fractures is more complex than the management of malunion of fractures elsewherein the skeleton.!, ", #, $%

&ood hand function depends on 'oint mobility, sensibility, good skin coerage, adeuate ascularity,and the gliding of a complex flexor and extensor tendon mechanism. *reexisting problems related toany of these factors may limit the usefulness of the digit, and surgical interention can causeadditional scarring and dysfunction. +onseuently, management of malunion in the hand is predicatedon a careful analysis of the risks and benefits of surgical interention and on the functional goals andthe likelihood that the operation can achiee them. !%

istory of the *rocedure

-ractures of the hand are among the most common fractures of the skeletal system. Most of these

fractures are acuired in the workplace or as a result of crush in'uries, falls, or sports in'uries.

Most of these in'uries can be managed nonoperatiely, but certain fractures, such as intraarticular

fractures, open fractures, unstable fractures, and displaced or angulated fractures, may reuire

surgical correction with /irschner wires (/wires), plates, or screws. If these fractures are not treated

properly, malunited fractures may result, leading to considerable loss of function and cosmetic

disfigurement. Malunited fractures inoling the 'oint surfaces can ultimately lead to

posttraumaticosteoarthritis.

*roblem

Most fractures of the hand bones occur in young, actie adults who are inoled in many arious

occupational and sporting actiities. If these fractures are not managed carefully, they may result inmalunion. This may lead to loss of function due to malalignment, malrotation, or shortening, which

may result in decreased and disordered motion of fingers and poor outcomes.

0pidemiology

-reuency

1trictly speaking, the term malunion implies union with abnormal anatomic alignment. oweer, in the

hand, this does not necessarily mean that there is a dysfunctional hand or finger, because this is not

often the case.

The freuency of malunited fractures may be high in the hands, but few of these malunions reuire

treatment. This is especially true with malunion of metacarpal neck fractures of the little fingers, which

seldom produce deformity or interfere with function and therefore typically reuire no treatment. "% In a

study by Tubiana, out of !2,222 hand in'uries, only #2 malunions reuired treatment. 3%

0tiology

Malunion of hand fractures may result from inadeuate treatment or failure of treatment. 4ccurate

anatomic restoration may not be the goal of nonoperatie treatment or een certain operatie

treatments for hand fractures. ence, inaccurate anatomic restoration after treatment may not be

considered eidence of inadeuate treatment.
http://emedicine.medscape.com/article/330487-overviewhttp://emedicine.medscape.com/article/330487-overviewhttp://emedicine.medscape.com/article/330487-overview


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*athophysiology

*atterns of malunion

Malunion is the most common bony complication of phalangeal fractures.The following four patterns

of deformity are recogni5ed6

Malrotation

7olar angulation

8ateral angulation

1hortening

Malrotation usually is seen after obliue or spiral fractures of the proximal and middle phalanges. The

best method of assessing malrotation is to ask the patient to make a fist and look for digital oerlap.

In adults with proximal phalangeal fractures, olar angulation exceeding "3#29 may result in

pseudoclawing. This deformity makes using the hand awkward and can result in a fixed flexioncontracture of the proximal interphalangeal (*I*) 'oint. The appearance may be aesthetically

unacceptable.

8ateral angulation and malrotation often occur concomitantly. If correction is considered, the

components of the deformity must be carefully identified.

1hortening may occur after a comminuted fracture is allowed to heal in a collapsed fashion or after a

long spiral fracture.

In malunion of metacarpal neck fractures, sunken knuckle may be the clinical presentation. It is more

of a cosmetic problem than a functional problem. In metacarpal shaft malunion, tendon imbalance and

intrinsic contracture of the *I* 'oint may occur: howeer, function may still be presered.

;ther aspects of malunion

Intraarticular malunion occurs when intraarticular anatomy is not restored.


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1caphoid malunion can alter carpal mechanics, leading to pain, weakness, limited motion, and

degeneratie arthritis.

Relation between metacarpal shortening and joint function

1ome authors hae performed cadaeric studies to find the relationship between metacarpal

shortening and extension of the M+* 'oint or the *I* 'oint. 1trauch et al obsered that for eery " mm

shortening of the metacarpal, there was a >9 lag in extension of the M+* 'oint. ?% oweer, this is not

seen clinically, because of the ability of the M+* 'oint to hyperextend.

7ahey et al found that for eery ! mm of shortening of the proximal phalanx, there was a !"9 lag in the

*I* 'oint extension.>% They also found that there was a linear relation between proximal phalanx

shortening and *I* 'oint extensor lag and that increased angulation of the phalangeal fracture led to

increased lag in extension of the *I* 'oint.

*resentation

istory

Malunited hand fractures are not usually difficult to diagnose. Most patients proide a history of in'ury

associated with the deformity. The form of treatment the patient receied should be noted. 1uch

treatment may include both nonoperatie measures such as splinting, immobili5ation, and

physiotherapy and operatie measures such as internal or external fixation or both.

The history must include the patient@s age, occupation, hand dominance, function and restriction of

hand function after the fracture, and the effect of the malunion on his or her actiities.

*hysical examination

+ommence the hand examination by comparing the affected hand with the unin'ured hand. Aote any

obious swelling or deformity. 8ook for the anatomic bony landmarks and their relations with each

other, and compare them with those of the healthy hand. 4bnormal positioning may indicate a

malunited fracture or tendon rupture or adherence. The deformity should be categori5ed in each

plane, to include the ulnarradial and the olardorsal plane. 4lso important is the rotational alignment.

(1ee the image below.)


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0xamination of the patient@s hand with the fingers flexed may clearly reeal a rotational deformity.

The most important aspect of the examination is the functional assessment of the hand. Because thefingers conerge with flexion and dierge with extension, certain deformities can be appreciated withthe fingers in flexion. The ability to make a complete fist must be assessed. Because the flexordigitorum profundus tendonsof the fingers work in unison, any restriction in the moement ordecrease in the length of one finger may seriously affect the power of the patient@s hand grip. ence, itmay notably interfere with normal function of the hand.

&rip strength should be measured by using a dynamometer, and the results can be compared withthose of the healthy hand. Aormal maximum grip strength is 3" k*a in men and #! k*a in women.The pinchgrip strength can be measured by using a manual pinch meter. oweer, a pinchgripanaly5er can be used to measure both pinch and grip strengths, and it may be a useful tool forob'ectiely assessing hand function.

The examination must include neurologic and ascular assessments. 4ny preious scar due tosurgery or in'ury should be assessed to facilitate the planning of incisions if surgery is contemplated.

Indications

Indications for surgery include pain, loss of function, cosmetic deformity, loss of motion in the

neighboring 'oint, and bony exostosis causing skin irritation and posing a threat of tendon attrition.

hen treating hand malunions, one must remember that the potential risks of surgery (eg, tendon

adhesions, 'oint stiffness) may outweigh any anticipated adantage.

The absolute contraindication for surgery is local infection. =elatie contraindications include

functionless limb, poor bone uality, and poor general medical condition.

maging 1tudies

Most malunited fractures of the hand can be detected with the help of plain radiography. The three

common iews (ie, anteroposterior, lateral, and obliue) yield adeuate information.

+omputed tomography (+T) and magnetic resonance imaging (M=I) may be helpful in theassessment of complex articular in'uries or carpal in'uries. In cases of carpal bone fractures,

radioisotope scanning may be useful.
http://emedicine.medscape.com/article/1245236-overviewhttp://emedicine.medscape.com/article/1245236-overviewhttp://emedicine.medscape.com/article/1241803-overviewhttp://emedicine.medscape.com/article/1238278-overviewhttp://emedicine.medscape.com/article/1238278-overviewhttp://emedicine.medscape.com/article/1245236-overviewhttp://emedicine.medscape.com/article/1245236-overviewhttp://emedicine.medscape.com/article/1241803-overviewhttp://emedicine.medscape.com/article/1238278-overview


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1urgical Therapy

The hand is a highly complex structure that reuires integrated function of extrinsic and intrinsic motor

units across a complex and limited bony and articular framework. The hand also functions as a

sensory organ and an organ of communication. 4ll these factors should be considered before

reconstruction is undertaken.

The goals of treatment are to restore disordered function and, occasionally, to correct cosmetic

deformity. 4ccordingly, the malunion should be carefully studied with an eye to understanding the

original deforming forces. Important principles in the management of malunions include the following6

=otational deformities are most disabling yet freuently not appreciated: a !29 rotational

malunion results in a "cm oerlap at the fingertip: alignment should always be checked with thefingers flexed in the palm

4n appropriate form of osteotomy and subseuent fixation must be tailored to each indiidual

deformity: familiarity with osteotomy techniues and alternatie forms of fixation affords flexibility intreating deformities

The soft tissues must be inspected carefully for scarring, adhesions, and contractures: carefulprotection of delicate structures by 'udicioustenolysisand arthrolysis may be needed at the time ofosteotomy

4ppropriate, functional, postoperatie rehabilitation is a must for good results: otherwise, een

the best surgery produces suboptimal results.

4 carefully planned osteotomy is necessary and must be executed with the least possible further

damage to soft tissues. Techniues of osteotomy must be tailored to the biomechanical reuirements

for proper realignment of the malunited fracture.

1eo et al described an osteotomy techniue for correcting malunion of the proximal phalanx that is

minimally inasie and is performed under local anesthesia. C% They reported that among the

adantages that this techniue offers is that it permits actie flexion and extension, which leads tomore accurate reduction and earlier recoery.

Malunion of phalangeal fractures

+linically significant malrotation results in functional impairment and usually necessitates osteotomy

through the phalanx or the metacarpal. (1ee the images below.)


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Distal metaphyseal malunion with volar displacement of the middle phalanx in a

9-year-old boy (same patient as in Images 7 and 8 in Multimedia!

Aote the lack of clinical deformity (same patient as in Images ? and C in Multimedia).


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in terms of function, the finger, including the portion at the distal interphalangeal 'oint, can be flexed completely as the

patient makes a fist (same patient as in Images ? and > in Multimedia).

*halangeal osteotomy corrects the malunion at its site of origin, allows simultaneous correction of

angular deformities, and permits concomitant softtissue procedures such as tenolysis or

capsulotomy. *halangeal osteotomies can be either stepcut or transerse, which are performed with

a power saw. 1tepcut osteotomies are fixed with either small 4; (Arbeitsgemeinschaft frOsteosynthese 4ssociation for the 1tudy of ;steosynthesis%) screws or /irschner wires (/wires):

transerse osteotomies can be held with a plate or with /wires.

Metacarpalbase osteotomies for malrotation correction can achiee up to !C!D9 of correction in the

index, long, and ring fingers, and up to "2#29 in the small fingers.

7olar angulation of "3#39 results in fixed flexion deformity of the proximal interphalangeal (*I*) 'oint.

This reuires correction by means of either closed or openwedge osteotomy and fixation with /pins.

The open wedge reuires a bone graft to fill the gap, whereas the closed wedge may result in

shortening of the finger.

8ateral angulation of phalangeal fracturesis corrected in the same manner as olar angulationEthatis, by performing osteotomies with a power saw.

1hortening due to a comminuted fracture that is allowed to heal in a collapsed fashion or that occurs

after a long spiral fracture can be corrected with an appropriately fashioned intercalary graft insertion.

hen a spiral fracture of the phalanx heals in a shortened position with a distal spike on the proximal

fragment, blocking flexion of the digit, careful remoal of the spike may be all that is reuired.


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Malunion of metacarpal fractures

Forsal angulation usually occurs in the second or third metacarpal and is bothersome, both

cosmetically and functionally, as it weakens the grip of the hand (see the images below). +orrection is

achieed with closed or openwedge osteotomies or fixation with /wires or 4; plates.

Metacarpal shaft malunion with dorsal angulation in the same patient as in Images #3 in Multimedia.


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Feformity of metacarpal malunion also becomes prominent when the fingers are flexed (same patient as in Images ", $,

and 3 in Multimedia).


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;bliue radiograph of the hand shows dorsal angulation (same patient as in Images ", #, and 3 in Multimedia).

4nteroposterior radiograph of the hand does not show any clinically significant deformity in that plane (same patient as

in Images "$ in Multimedia).

The closed wedge is preferred oer the open wedge for two reasons. -irst, healing of only one

surface is reuired, unlike the open wedge, in which healing of two surfaces is reuired. 1econd, the

intrinsics can accommodate some shortening with a closed wedge, whereas with an open wedge,

lengthening of the bone occurs. 1uch lengthening may aggraate the intrinsic tightness, especially

when posttraumatic intrinsic muscle contracture has occurred.

=otational malunion results from oerlapping of the affected finger oer the ad'acent finger. +osmetic

deformity is often marked, and grip is impaired. +orrection is achieed through a metacarpalbase

osteotomy. Furing the operation, a longitudinal mark is made on the metaphysis with an osteotome

prior to the osteotomy. Then, the osteotomy is performed with a power saw perpendicular to the mark.

The rotation is corrected and fixed with seeral /wires or 4; plates.

Intraarticular metacarpal malunionsare difficult to correct with osteotomies. oweer, correction can

be achieed by maintaining reduction with screws and plates or with screws and cancellous bone

grafts.#%

Malunion in carpal bones

The scaphoid is the usual site for carpal malunion. Malunion of other carpal bones is rare. Malunion of

the scaphoid is best preented. If malunion of the scaphoid is detected soon after union, correctie

osteotomy can be considered. 8ate malunion of the scaphoid is best managed symptomatically.

-inally, scaphoid cheilectomy or radial styloidectomy can be considered if symptoms persist.


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;ptimal site for osteotomy

hether osteotomy for malunion of metacarpals and phalanges in the hand should be done at the

original fracture site or at a separate site is a matter of debate. +orrection at the fracture site is

generally preferred, in that it addresses the issue at the site of pathology (ie, malunion) and thus can

correct the combined deformity (translation, rotation, and angulation). -urthermore, it enables thesurgeon to perform tenolysis and capsulolysis at the same time. It especially aoids the 5ig5ag

deformity produced by the osteotomy away from the fracture site.

4 correctie osteotomy performed at the leel of the fracture site is called a focal osteotomy, whereas

one performed away from the original fracture site is called an extrafocal osteotomy.

0xtrafocal osteotomies do not restore the normal anatomy. oweer, there are instances where this

may be preferred, as in the case of a malunion resulting from a complex or compound fracture that

can be treated by a single osteotomy rather than a focal osteotomy. The latter may hae to be

complex, and the metacarpal or the phalanx may not lend itself to such a complex procedure.

0xtrafocal osteotomy is also preferred in articular malunions when there is enough 'oint space or if the

articular fragment is too small to be interfered with.

;peningwedge s closingwedge osteotomy

Basically, an osteotomy can be a closingwedge or an openingwedge procedure. 4 closingwedge

osteotomy has the adantage of inherent stability with no additional bone graft: howeer, it shortens

the digit. 4n openingwedge procedure may need a structural bone graft, but this is not always the

case, as when secure fixation is obtained with a plate and screw, where cancellous bone graft can be

used as supplementation.

1ecuring of osteotomy

4s with any other fracture, different options are aailable, including plaster immobili5ation, /wire

fixation, plateandscrew fixation, and external fixator application. 4n osteotomy can be left alone only

if there is inherent stability at the osteotomy site, which can occur with stepcut osteotomies. Basal

osteotomies can be held with /wires. oweer, plateandscrew fixation is preferred for rigid fixation

and immediate postoperatie mobili5ation to preent stiffness and adhesions and, thereby, improe

function.

Timing of osteotomy

The timing of operatie interention is ital, especially in malaligned fractures proceeding to

established malunion. If the fracture malalignment is addressed surgically within !2 weeks, then thefracture site can be exposed, the callus can be remoed to recreate the original fracture, and the

fracture can be managed with appropriate fixation.

hen functional loss is predicted from the amount of malalignment at the time of ealuation, there is

little alue in waiting to perform the correction. oweer, in cases with milder deformities, it is better to

wait to do a correctie osteotomy until the degree of functional loss can be estimated.

*rocedural details

4deuate surgical planning reuires adeuate preoperatie assessment. The patient@s neuroascular

status should be assessed before any interention is performed. Intraoperatie fluoroscopy orradiography should be used to ensure that adeuate fixation is achieed before the patient leaes the


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operating room. Goint motion should be assessed after fixation so that postoperatie expectations can

be established.

Most surgery in the hand is undertaken to promote function. 0arly mobili5ation is essential to ensure a

good outcome. Felaying motion beyond # weeks leads to arthrofibrosis and a poor functional

outcome. ;ptimal surgical treatment should allow for adeuate postoperatie motion, and to achiee

a good outcome, patients should be encouraged to moe their fingers daily.

;utcome and *rognosis

If treated carefully, with adherence to the principles described, most phalangeal and metacarpal

malunions heal without clinically significant complications. +omplications may include recurrence of

deformity, neuroascular complications, or both.

1ome patients may deelop stiffness and decreased mobility. Most poor results are documented in

elderly patients (H?3 years) and in patients with crush in'uries or extensie softtissue contractures. 4

combination of these factors increases the risk of compromised results. *roper selection of implants

and uick rehabilitation may improe the prognosis.

In a study comparing "!C littlefinger metacarpal shaft and neck fractures treated nonoperatiely (with

no attempt at fracture reduction) with $$ treated operatiely with fracture reduction and fixation,

seerity of palmar angular deformity did not affect the outcome of nonoperatiely treated fractures."% There were no differences in outcome between operatiely treated and nonoperatiely treated

metacarpal neck fractures: and Fisabilities of the 4rm, 1houlder, and and (F41) scores and

aesthetic outcomes were better for metacarpal shaft fractures treated nonoperatiely than for those

treated operatiely.

*oten5a et al reported clinical and radiographic mediumterm results for "$ fingers in "2 patients who

underwent surgery for posttraumatic malunion of the proximal phalanx. D% In all cases, correctie

osteoclasia or osteotomy was done at the malunion site, followed by miniplate and screw fixation or

by screw fixation only. +orrectie osteoclasia was performed when malalignment was addressed

within ? weeks after in'ury. Two patients who had two fractures underwent additional surgery to

improe function and range of motion.

-inal followup occurred at a mean of "$ months after correctie surgery. D% &ood or excellent clinical

and radiographic results were obtained for all patients. 4n improement in grip strength was

demonstrated by all patients. The mean score on the F41 symptom scale was 3 points. The

researchers concluded that in situ osteotomy, in con'unction with stabili5ation by miniplates or screws,

is effectie for correcting posttraumatic malunions of the proximal phalanges of the fingers.

-uture and +ontroersies

In the future, expanded use of bioabsorbable implants made of polyglycolic acid or poly8lactic acid

may hae adantages oer the traditionally used pins, screws, and plates. These bioabsorbable

plates will help aoid the need for second procedures to remoe implants, which are the main causes

of loss of function from iatrogenic causes. -urther deelopment of lowprofile implants with high

tensile strength will allow adeuate mobility during postoperatie rehabilitation and, thereby, help

preent stiffness.

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New Malunion Background