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In diabetic patients, the incidence of neuropathy is high 30% to 50%,3 but neuropathic fractures occur less commonly, with an incidence of only 1.0% to 2.5%.2,4 Typically, neuroarthropa-

We are accustomed to thinking of

foot and ankle fractures in the

patient with diabetes as ÒCharcot

injuries.Ó Although this

terminolo-gy does describe a disease process,

it is now of historic interest only;

the term ÒneuroarthropathyÓ more

correctly describes the rapid onset

of painless and severe joint

destruc-tion This disease process was

dis-cussed by Charcot in 1868 with

ref-erence to a patient with locomotor

ataxia and posterior column

dys-function of the spinal cord (tabes

dorsalis).1 In 1936, Jordon was the

first to associate diabetes with

neu-roarthropathy.2 Fractures and

dis-locations are part of the spectrum of

this arthropathy, which has a

var-ied presentation The sine qua non

of neuroarthropathy is architectural

disruption and disorganization of

the foot either in the absence of

pain or without an appropriate

level of pain.2

In the 19th century, syphilis was

a common cause of this form of arthropathy Today, although the major cause of neuroarthropathy worldwide is leprosy, most pa-tients with neuroarthropathy in the United States have diabetes Other causes include alcohol-induced peripheral neuropathy, syringo-myelia, and congenital indifference

to pain In diabetic patients, the incidence of neuropathy is high (30% to 50%),3 but neuropathic fractures occur less commonly, with an incidence of only 1.0% to 2.5%.2,4 Typically, neuroarthropa-thy occurs in patients who have had diabetes for 10 years or more, and the incidence of this condition rises with the duration of dia-betes.2,5,6 On rare occasions, how-ever, neuroarthropathy coexists with the first presentation of dia-betes mellitus.2 Interestingly, neuro-arthropathy in the contralateral

foot occurs at a higher frequency (approximating 30%) than in the initially involved foot.2 Whether this increased propensity repre-sents a predisposition to the devel-opment of neuroarthropathy or is a result of increased load bearing in the uninvolved foot is not under-stood.7 In diabetic patients with renal disease, not only the inci-dence but also the morbidity of neuroarthropathy increases dra-matically.4,8

Pathophysiology

In the early stages of neuroar-thropathy, cartilaginous fibrillation and narrowing with subchondral and endochondral bone formation occur in the affected joint In later stages, the destructive changes are marked at the points of contact between the two articular surfaces,

Dr Myerson is Director, Foot and Ankle Service, Department of Orthopaedic Surgery, Union Memorial Hospital, Baltimore Dr Edwards was a Fellow, Department of Orthopaedic Surgery, Union Memorial Hospital.

Reprint requests: Dr Myerson, Union Memorial Hospital, Johnston Professional Building No 400, 3333 N Calvert Street, Baltimore, MD 21218.

Copyright 1999 by the American Academy of Orthopaedic Surgeons.

Abstract

Neuroarthropathy, a rapid, painless destructive process, has become increasingly

prevalent among long-lived diabetic patients It is characterized by warm,

swollen joints with a grossly disorganized radiographic appearance, in spite of

which the patient is often pain-free Neglect of this condition results in

progres-sive deformity or instability, often complicated by ulceration and infection,

which can ultimately result in loss of independent mobility, loss of the affected

limb, and even death In most cases, a plantigrade, stable, and functional foot

can be achieved with simple nonoperative techniques, such as the use of a

total-contact cast or shoe modification A few patients in whom uncontrolled

instabil-ity or major osseous prominences cause recurrent ulceration will require

recon-structive surgery (either exostectomy or osteotomy/arthrodesis) Although some

patients will have an improvement in function, ongoing vigilance is necessary.

J Am Acad Orthop Surg 1999;7:8-18

in the Foot and Ankle

Mark S Myerson, MD, and William H B Edwards, MB, BS, MS, FRACS

resulting in fragmentation of

artic-ular cartilage, destruction of

liga-ments, eburnation, and bone

ab-sorption Massive osteophytes,

loose bodies, and often periosteal

bone are formed The joint capsule

and synovium become thickened

and edematous, initially with

vas-cular spaces but later with fibrous

tissue Microscopic bone debris

and cartilage in the capsule are

considered by some to be

pathog-nomonic of the process.9

Limited sensation combined with

active use (but not necessarily

over-activity) is required for a

neuro-pathic fracture to develop.2,10,11 For

example, neuroarthropathy is seen

only in active patients with

neurop-athy, but not in inactive patients

with neuropathy (e.g., patients with

spinal injuries) Although

neuro-arthropathy seems to develop after

cumulative stress to the foot, it can

occur after a single episode of acute

trauma

Patients with neuroarthropathy

have satisfactory (but not normal)

circulation to the foot; Doppler

indices are typically greater than

0.6 in most patients.4,12 It is likely

that perfusion of the foot is in some

way related to this disease process,

which may be associated with

autosympathectomy,13 producing

increased blood flow and bone

resorption

The initial radiographic change

in acute neuroarthropathy is

usual-ly a fracture associated with joint

subluxation This sequence is not

always present, and gross

deformi-ty may develop in the absence of a

fracture, particularly in the

mid-foot This is clearly a stress-related

or overuse phenomenon in which

ligamentous failure occurs before

fracture Altered collagen

cross-linking, because of either

dia-betes14,15 or autosympathectomy,

makes ligaments brittle, inelastic,

and susceptible to trauma Minor

injury leads to disruption of the

lig-amentous support of the midfoot

and, in the absence of protective sensation, a rapidly worsening and unstable dislocation

Evaluation and Diagnosis

The typical patient with acute neuro-arthropathy presents with painless deformity of the foot, erythema, and swelling Depending on the length of time since the initial

trau-ma, minor instability, ligamentous disruption, or fracture-dislocation may be present Unfortunately, the diagnosis of acute neuroarthropa-thy is frequently delayed and is often missed completely In the acute phase, as a result of the asso-ciated erythema and swelling, patients are frequently treated for presumed infection Although most patients do not report pain, it

is important to remember that acute neuroarthropathy may be painful.2,9 If pain exists in the pres-ence of acute or chronic neuro-arthropathy, the clinician should suspect associated infection

The differential diagnosis in-cludes gout, cellulitis, and osteo-myelitis The absence of systemic signs (e.g., fever, elevated white blood cell count, and elevated sedi-mentation rate) and the presence of

a normal blood glucose level effec-tively eliminate infection as part of the differential diagnosis If the diagnosis of infection is still in doubt, a trial of 2 hours of bed rest and elevation of the limb will be helpful; the swelling associated with acute neuroarthropathy will subside rapidly,3 whereas that associated with infection will not

Patients with diabetes who pre-sent with foot deformity or find-ings suggestive of neuroarthropa-thy should be carefully examined for sensory deficit by assessment of light-touch and two-point discrimi-nation The most accurate and clin-ically applicable means of evaluat-ing sensation in the office settevaluat-ing is

testing with Semmes-Weinstein monofilaments If a patient is able

to perceive sensation when the 5.07 monofilament is used, protective sensation is present

Although most patients with neuroarthropathy have reasonable perfusion of the foot, it may be marginal or inadequate for those who require surgical procedures

A Doppler ultrasound evaluation

of the foot should be performed routinely Healing after surgery is more likely if the Doppler ultra-sound indicates pulsatile flow and the ankle-brachial index is greater than 0.45.16 In our previous re-port,4the average was 0.65, con-firming adequate perfusion in most feet

Radiographs should be obtained with the patient bearing weight; however, this is often not possible due to poor proprioception or con-tralateral amputation Radio-graphs will usually display gross disorganization related to the stage

of the arthropathy, although early

in the course of the disease these findings may be extremely subtle.2

Two patterns of neuroarthropathy have been described: (1) an atrophic pattern, with massive bone resorp-tion and joint disintegraresorp-tion, and (2) a hypertrophic pattern, with joint destruction, periarticular bone formation, fractures, osteophytes, bone debris, and migration of the bone fragments The second pat-tern is seen more often in the ankle than in the foot.17

Unless the fracture or disloca-tion is associated with an ulcer or

an open wound on the foot, osteo-myelitis is rare Magnetic reso-nance imaging can define the pres-ence (or establish the abspres-ence) of soft-tissue infection, but it does not differentiate well between neuro-arthropathy and osteomyelitis because both are associated with bone edema.2 Simultaneous indium-labeled white blood cell scanning and technetium-labeled

polyphos-phate scanning (dual-window

imaging) may be more helpful in

diagnosing infection.2

Staging and Classification

In 1966, Eichenholtz9 described a

combined clinical and

radiograph-ic staging system In stage I, the

foot is inflamed, edematous, and

erythematous, occasionally with a

precipitous onset Radiographs

typically show bone

fragmenta-tion However, this finding may

be subtle, particularly in the

pres-ence of joint subluxation or

dislo-cation, rather than fracture In

stage II, the reparative process

begins The swelling, erythema,

and warmth regress, and

radio-graphs demonstrate coalescence

and resorption of bone fragments

In stage III, inflammation is absent

(resolved), and consolidation of

the bone is radiographically

evi-dent.2,9 Stage III, therefore, implies

stability but not necessarily

chroni-city, because the foot may remain

unstable over a long period of time

despite coalition of fragments and

bone healing This scenario is

par-ticularly applicable to the hindfoot,

where bone healing may have

occurred but the foot is clinically

unstable, with a rocker-bottom

deformity; in these circumstances,

regardless of chronicity, stage III

has not been reached.3

The anatomic classification

pro-posed by Brodsky2is clinically useful

because it highlights the anticipated

duration of treatment required and

facilitates more accurate comparative

evaluation of deformity Type I (60%

of cases) involves the tarsometatarsal

and naviculocuneiform joints It is

rarely associated with chronic

insta-bility and is ultimately characterized

by symptomatic plantar osseous

prominences Although feet with

type I neuroarthropathy are stable,

they are usually deformed, which

may cause ulceration depending on

the magnitude and location of the deformity.2,3 Type II (20% of cases) involves the subtalar, talonavicular, and/or calcaneocuboid joints; the feet are often grossly deformed and unstable and need longer periods of immobilization Type IIIA produces the most severe instability, due to dis-solution of the talus and ankle, and frequently involves marked varus or valgus with a prominent malleolus, leading to ulceration and infection

Type IIIB is a pathologic fracture of the calcaneus that often leads to pro-gressive secondary pes planus and Achilles tendon insufficiency

General Principles of Management

The goal of treatment should be to create or maintain a stable, biome-chanically sound, plantigrade foot that can fit in a shoe or brace

When planning treatment, the clini-cian must consider the particular pattern of injury, the age and activ-ity level of the patient, the degree and expected progression of the consequent deformity, the stage of the disease process, and the pres-ence of complications, such as ulceration or infection.4,18 The problems caused by neuroarthrop-athy are usually due to either os-seous prominences or persistent instability.2

Although most patients can and should receive nonoperative care for neuroarthropathy, surgery may

be essential for some patients with either acute or chronic disease In all cases, patient education in

prop-er foot care and the avoidance of injury is vital Whatever treatment approach is selected, the patient must be made aware of the severity

of the disease process Because of neuropathy, however, these pa-tients simply do not recognize the harmful effect of bearing weight on the affected extremity and, despite all advice to the contrary, continue

to damage their feet The need for vigilance regarding the onset of ulceration and infection is therefore essential

Nonoperative Modalities

Most cases of neuropathy of the foot or ankle can be satisfactorily managed with nonoperative meth-ods of treatment Prolonged im-mobilization is generally the key to

an ideal outcome.2,4,10,11 The prin-ciples of this approach are to con-trol swelling, to provide skeletal stability, to protect the soft tissues for an extended period, and to ensure even distribution of forces

on the weight-bearing surface of the foot In the acute stage (Eich-enholtz stage I), closed manage-ment involves the reduction of swelling by elevation and rest; in patients with severe swelling, the use of intermittent compression may also be necessary.19 Once the severe swelling has been reduced,

a total-contact cast provides some stability, distributing pressure across the plantar weight-bearing surface of the foot more evenly than a regular cast When the swelling decreases further and stage II approaches, a removable boot or short leg cast will provide external stability for most pa-tients.20 In stage III, the goal is to provide even distribution of force over the weight-bearing surface of the foot This is usually accom-plished with a custom-made ortho-sis, an accommodative shoe, or a protective brace, such as an ankle-foot orthosis (usually necessary for the long-term management of the hindfoot)

There is the potential risk of devel-oping neuroarthropathy after an acute sprain or fracture.3,10,11,18 In general, these injuries are treated in a manner similar to that utilized for patients without neuropathy If indi-cated, surgery should not be delayed

or avoided simply because the patient is diabetic If the injury is

managed with inadequate

immobi-lization, a rapidly developing

neuro-arthropathy may ensue If the foot or

ankle fracture is nondisplaced or

minimally displaced and has a stable

configuration, closed management

with prolonged casting is an

accept-able alternative, but only with close

supervision If the fracture is

dis-placed and either considerable

manipulation is needed to reduce it

or molding is required to maintain

the reduction, an open approach with

internal fixation is recommended

Regardless of the method of

treat-ment, prolonged immobilization is

often necessary to prevent the

devel-opment of neuroarthropathy

Pa-tients with diabetes and neuropathy

may require double the normal

peri-od of immobilization, maintaining

non-weight-bearing status for 10

weeks and then weight bearing in a

cast for an additional 2 to 4 months or

until all warmth and swelling have

dissipated

Reconstructive Surgery

Reconstructive surgery in the

setting of neuroarthropathy is

tech-nically challenging If surgery is

contemplated, the risks of failure of

fixation, wound problems, sepsis,

and amputation should be made

clear to the patient Furthermore,

surgery should not be undertaken

if the surgeon is unfamiliar with

treatment of the insensate foot

Successful management requires a

sophisticated team approach,

in-volving specialists in infectious

dis-ease, vascular surgery, physical

therapy, rehabilitation, and

pros-thetics

During the acute phase, the foot

is hypervascular, soft-tissue

cover-age is potentially compromised,

and, due to osteopenia,

fragmenta-tion of bone makes fixafragmenta-tion

chal-lenging Regardless of the location

of the arthropathy, open reduction

and internal fixation alone is

gener-ally unsatisfactory, and primary

arthrodesis is usually required to

stabilize the foot further.4 In the acute stage, surgery is needed pri-marily to prevent soft-tissue dam-age (i.e., skin necrosis due to pres-sure of the dislocated bone or other skin problems secondary to cast molding necessary to maintain reduction) Surgery should be con-templated only if the bone will support adequate fixation For this reason, it is rarely appropriate to operate on the foot, regardless of the pattern of dislocation, if more than 6 weeks has elapsed since the onset of acute neuroarthropathy It

is often difficult to ascertain exactly when the process commenced, because the patient can rarely rec-ognize the initial event or the onset

of neuroarthropathy Surgical cor-rection is more frequently an alter-native when there is a dislocation without fracture, but is contraindi-cated if bone fragmentation is already substantial

Reconstruction of the more chronically deformed, unstable foot may be performed in either the subacute or the chronic stage when cast, brace, or shoe modifications can no longer control recurrent ulceration However, one must determine that the efforts at these treatments have in fact been ade-quate, because most stable defor-mities, regardless of their magni-tude or the appearance of the foot, are well accommodated in an appropriate brace or shoe If recur-rent ulceration occurs, one should first determine whether the protec-tion afforded the foot was adequate before proceeding to surgery

A successful reconstructive pro-cedure depends on a minimum of soft-tissue swelling, reasonable bone quality to support solid fixation of internal devices, adequate

vasculari-ty, and the absence of infection The last-mentioned criterion is some-times difficult to achieve because patients with chronically deformed feet or ankles and severe destructive neuroarthropathy often have

associ-ated infection The surgical plan-ning of the reconstruction must therefore take this into account, because the alternative is amputa-tion Surgery should not be per-formed if the foot or extremity is swollen The reduction of swelling before commencing surgery may be accomplished with 24 hours of bed rest, limb elevation, and mild diure-sis An intermittent foot compres-sion pump can be used for 12 hours immediately before surgery if swelling remains a problem How-ever, in the patient with neuropathy, this device should be used

cautious-ly because of the lack of protective sensation

In all patients, the operative tech-nique is of paramount importance The soft tissues are marginally viable and must be treated cautious-ly; longitudinal incisions should be made directly to bone without superficial subcutaneous dissection Incisions on the plantar weight-bearing surface of the foot should be avoided while maintaining broad skin bridges and using minimal skin retraction.21 Although this ap-proach usually traumatizes superfi-cial sensory nerves, in these cases the foot is already insensate A tourniquet is not used, and all surgery on the insensate foot is per-formed with local or regional ankle-block anesthesia When bleeding impairs visualization, an Esmarch bandage can be applied

temporari-ly In all cases, arthrodesis is ac-complished with rigid fixation and

is accompanied by aggressive resec-tion of fibrous tissue, cartilage debris, and synovium; resection of sclerotic bone to achieve congruent bleeding surfaces that provide max-imal contact and stability; judicious use of bone graft; and reduction of soft-tissue tension with wound clo-sure.22 Autogenous cancellous bone graft is generally used, but if an adequate quantity of autogenous bone is not available, allograft may

be considered

Realignment with open

reduc-tion is followed by arthrodesis of

the involved joints Wherever

pos-sible, rigid screw fixation of the

involved bones is used, but due to

the difficulty encountered with poor

bone quality and osteopenia, it may

be necessary to extend the screws

across joints into uninvolved bones

When internal fixation is difficult,

supplemental external fixation may

be appropriate, but the use of any

external fixator must be approached

cautiously because of the possibility

of infection However, excellent

results have been obtained with a

ring fixator, and in the presence of

gross instability (particularly of the

ankle), an external fixator may be

used to supplement internal

fixa-tion A ring fixator can be used in

the presence of infection When

sta-ble fixation of the hindfoot and

ankle is required, a tibiocalcaneal or

tibiotalocalcaneal arthrodesis can be

performed with the use of an

intramedullary nail

Postoperatively, the extremity is

immobilized in a bulky bandage

with copious cotton padding and

posterior or U-shaped plaster

splints Intravenous antibiotic

pro-phylaxis is used for 48 hours Bed

rest with strict elevation of the limb

is required for the first week

Pa-tients should be carefully evaluated

to ensure compliance with respect

to restricted weight bearing If the

patient is totally unable to comply,

transfer to a chronic-care facility for

the appropriate duration is

neces-sary until unrestricted ambulation

can begin Ten days after surgery,

the first dressing change is

per-formed, and a short leg cast is

ap-plied Sutures are typically left in

place for 3 to 4 weeks, unless

wound healing is clearly complete

at an earlier time

The length of postoperative

cast-ing and protected weight bearcast-ing is

determined on the basis of the

loca-tion of the reconstructive

proce-dure and the extent of apparent

healing Typically, a non-weight-bearing cast is used for 2 months, followed by a weight-bearing cast

or a cast brace for 4 (midfoot), 6 (hindfoot), or 9 (ankle) months

These times are quite variable, however; the temperature of the foot and the presence of swelling are used as indications of bone and soft-tissue healing Once tempera-ture and swelling have subsided to more normal levels as compared with the contralateral foot, weight bearing in a cast can commence A cast brace or shoe is gradually introduced as early as possible without jeopardizing the recon-structive effort If the patient is reliable and the fracture or arthro-desis is healing, a removable cast brace is applied at 4 to 6 months and remains in place until the extremity

is completely stable

Management of Neuroarthropathy in the Midfoot

Neither the initial nor the final appearance of the foot should be of major concern to the patient or the treating physician because, despite gross deformity of the midfoot, a shoe can still be fitted The vast majority of patients with acute midfoot neuroarthropathy may be treated nonoperatively

Nonoperative Approach

Although manipulation of the midfoot might temporarily reduce a dislocation, this procedure should not be attempted because of the pressure required to obtain and maintain the reduction Any undue pressure in the insensate foot will lead to superficial and possibly deep skin loss and infection Fur-thermore, there are such rapid fluc-tuations in the swelling of the foot that the reduction is rarely main-tained However, when treating an early neuroarthropathy with

mini-mal subluxation and little fragmen-tation, application of a well-padded and molded cast is preferable in an effort to prevent increasing defor-mity Unfortunately, the deformity may worsen in spite of these pre-cautions Such worsening occurs predominantly because the patient

is unable to comply with restricted weight bearing, although it is possi-ble that increasing deformity may occur due to gross ligamentous lax-ity and tendon forces across unsta-ble joints

The cast should be changed at weekly intervals for 2 to 3 weeks and then at 2- to 3-week intervals, depending on the amount of swell-ing A total-contact cast is not neces-sary, as non-weight-bearing status should be maintained Ambulation

in a cast is begun after the extreme swelling and warmth begin to sub-side (usually at about 6 to 8 weeks), signifying the beginning of bone healing and the commencement of Eichenholtz stage II At this time, the cast is changed at 3- to 4-week intervals until a stable stage III is reached

Surgical Approach

If the fracture or dislocation is grossly unstable, if the presence of severe deformity precludes fitting into a shoe, or if the soft tissue is at risk from an underlying bone prominence, then open reduction with internal fixation and arthrode-sis should be considered (Fig 1) Although this approach to opera-tive treatment of the insensate foot may seem aggressive, there is suffi-cient clinical evidence that a care-fully monitored operative approach

to the acute unstable midfoot has substantial benefit.4

Before deciding on a surgical treatment regimen, the clinician should assess the magnitude of the deformity and determine whether the surgical support team can ade-quately manage the patient It is preferable to treat a patient

nonoper-atively than to embark on a

compli-cated and time-intensive treatment

program with potentially disastrous

consequences attributable to an

ill-prepared or inexperienced team

Acute Stage (Eichenholtz Stage I)

The procedure begins with two

or three longitudinal incisions,

depending on the severity of the

dislocation The first incision is

medial, between the plane of the

anterior and posterior tibial

ten-dons, exposing the medial column (which is invariably involved) A second dorsal longitudinal incision

is made between the second and third metatarsal bases, extending from the middle of the shafts of the metatarsals proximally to the navic-ular or talus, depending on the need for exposure of these bones

Occasionally, a third incision is made along the lateral column, dor-sal to the fifth metatardor-sal, exposing the metatarsocuboid joint

Rigid internal fixation should be used Cannulated self-drilling and self-tapping partially threaded screws of various diameters offer the greatest ease of insertion (Fig 1,

C and D) Smaller screws may not hold dislocations adequately, par-ticularly if it is necessary to gain purchase more proximally in bone

of better quality Insertion of a larger screw from the first meta-tarsal proximally into the cuboid or calcaneus (i.e., from one stable sec-tion through an unstable segment into another stable portion of the foot) provides the desired greater bone purchase

On occasion, a medially or plan-tarly applied one-third tubular plate or an H plate can be used to increase stability.18,23 The applica-tion of a plate on the plantar surface

of the midfoot has been particularly useful for stabilizing the metatarso-cuneiform and metatarso-cuneiform-navicular joints.18 Although this system is biomechanically stronger than the use of dorsally applied screws, the exposure is considerably more diffi-cult

Postoperatively, a short leg cast

is applied This cast is changed every 2 to 3 weeks, and weight bearing is not allowed for 8 to 10 weeks Once swelling and warmth settle (stage II), weight bearing is commenced in a well-fitted and well-padded short leg cast, which

is changed every 2 weeks until the foot is stable, as indicated by the absence of swelling and warmth and the appearance of fusion on radiographs A removable cast-boot may be used instead of a cast, but the patient must be informed about the risks of walking without support

Subacute Stage (Eichenholtz Stage II)

During this stage, inflammation decreases, and there is radiographic evidence of progressive bone frag-mentation and resorption, making surgical fixation extremely tenuous

Fig 1 Preoperative anteroposterior (A) and lateral (B) radiographs of a patient with

mid-foot neuroarthropathy Postoperative anteroposterior (C) and lateral (D) radiographs

were obtained after reduction and stabilization with cannulated screws.

Therefore, surgery is avoided except

for the treatment of infection or

truly recalcitrant ulceration, which

is seen if the foot is grossly unstable

The ideal treatment is nonoperative

management with weight-bearing

in a total-contact cast or cast-boot,

similar to the approach described

for stage I Once the foot has

stabi-lized, a gradual transition is made

to custom-made orthoses and shoes

A severely unstable foot with a

rocker-bottom deformity may not

adequately fit in a shoe; a molded

ankle-foot orthosis may be required

The unstable midfoot is extremely

difficult to manage, and recurrent

ulceration is most likely to occur

If surgery is required, the

ap-proach is similar to that described

for stage I midfoot disease

How-ever, ulceration is often present,

and whenever possible, one should

avoid surgery if there is an open

wound In these situations, a

total-contact cast should be applied.24

When the ulcer has healed, surgery

should be performed immediately

If the ulcer will not heal but

sur-gery is deemed necessary, extreme

care should be exercised to prevent

postoperative wound

complica-tions

During the period of transition from contact casting to orthotic management, close monitoring is required to prevent recurrence of stage II signs or the development of ulceration.4,18 Occasionally, the foot does not regain stability; in such cases, long-term management in a molded total-contact Òclam shellÓ brace or a Charcot restraint orthotic walker, or ÒCROW,Ó20is an excel-lent option

Chronic Stage (Eichenholtz Stage III)

When the condition stabilizes (stage III), patients typically have relatively rigid and often deformed feet.4 As previously described,2,4,21

management with custom-molded insoles and shoe modifications is most often effective However, sur-veillance for additional foot prob-lems (particularly ulceration) is essential; patient education in this regard is vital It must also be remembered that neuroarthropathy may occur in the same foot at a later date, although it is rarely at the same site; this is particularly so in the case

of neuroarthropathy of the midfoot.4

In cases of recurrent ulceration and underlying bony prominence in

a stable midfoot, the deformity

should be surgically addressed by simple exostectomy.2,4,21 However,

it is important to be aware that a stable midfoot with an exostosis can

be converted to an unstable midfoot

by performing an exostectomy.4 It

is unusual for a stable foot to require a realignment osteotomy and arthrodesis to prevent recur-rent ulceration, particularly if the prominence is medial and lateral and off the weight-bearing surface

An unstable midfoot requires realignment and stabilization, usu-ally via a closing-wedge osteotomy and arthrodesis with internal screw fixation4or use of a medial or plan-tar plate (Fig 2).18,23 Achilles ten-don lengthening is always neces-sary in treating hindfoot equinus

In patients with marked bone loss, threaded Steinmann pins may pro-vide better stability

After a realignment procedure, the foot needs an extended time (5

to 10 months) in cast immobiliza-tion until the osseous surfaces are united.4 Amputation may be a more acceptable option for patients

in whom the condition recurs after midfoot realignment; in such cases,

a great effort should be made to maintain limb length.4

Fig 2 Midfoot neuropathy A, Preoperative lateral radiograph B, Lateral radiograph obtained after application of plantar plates.

Management of

Arthropathy in the

Hindfoot and Ankle

General Principles

It is important to identify

neurop-athy in a patient with an acute

ankle fracture because such a

pa-tient is at risk for rapidly worsening

neuroarthropathy Therefore, the

patient must be carefully monitored

during treatment Diabetes is not a

contraindication to open reduction

and internal fixation, but the

pres-ence of neuropathy means that

pro-longed immobilization is required

to prevent the development of

neuro-arthropathy.18 This scenario is

dif-ferent from that of the patient who

presents in an acute, subacute, or

chronic stage of established

neuro-arthropathy and is therefore at

marked risk for worsening

defor-mity regardless of the form of

im-mobilization used In such patients,

the weight-bearing axis of the lower

extremity no longer falls within the

center of the ankle joint due to

varus or valgus deformity, but is

usually medial or lateral to it For

this reason, despite adequate brace

or cast support, the deformity may

worsen

In the acute and subacute stages,

management primarily involves a

well-molded short leg cast until

sta-bility is reached.12 In many cases,

however, weight-bearing must be

delayed until the acute

inflamma-tion and swelling have subsided

For example, it is difficult to

deter-mine accurately whether a stable

stage has been reached with chronic

dissolution and fragmentation of

the talus (Fig 3) In such cases,

weight-bearing can commence

when the subacute phase is reached,

provided the talus is centered under

the tibia and remains in the line of

the weight-bearing axis of the lower

limb If progressive dissolution of

the talus occurs, the consequences

are not as serious as they are when

medial and lateral talar subluxation

occur because the foot remains plantigrade, and varus or valgus instability and deformity are less likely to occur

The indications for operative intervention include marked insta-bility, fixed deformity not manage-able with a total-contact cast, and recurrent ulceration and infection refractory to brace and cast treat-ment.12 In these settings, open reduction and arthrodesis of the involved joints is the procedure of choice and may require tibiotalar arthrodesis, tibiocalcaneal arthro-desis after talectomy, or triple or pantalar arthrodesis.12 Ideally, rigid internal fixation with large cannu-lated screws is used, but persistent ulceration, infection, or osteopenia may dictate the use of an external fixation device Accurate alignment (ankle in neutral to 5 degrees of dorsiflexion, 5 to 10 degrees of hindfoot valgus, and external rota-tion matching that on the contralat-eral side) is essential to prevent maldistribution of force and ulcera-tion in the postoperative period.12

Postoperatively, non-weight-bearing status should be

main-tained with use of a cast for 2 to 3 months Thereafter, protected weight bearing is allowed until arthrodesis is evident both

clinical-ly and radiographicalclinical-ly or until a stable pseudarthrosis is believed to

be present It is important to real-ize that arthrodesis is not necessary

to achieve a successful outcome because stability is the goal of surgery In our previously reported series,12 more than 90% of the patients achieved a successful out-come with salvage of a severe deformity Success should be equated with a stable, noninfected extremity that fits in a brace Most patients who have under-gone an extended hindfoot or ankle fusion must be protected in

a brace, usually an ankle-foot orthosis Stress fracture of the dis-tal tibia may occur if no brace is used, probably due to the in-creased concentration of force in the distal portion of the leg (Fig 4) The use of intramedullary devices has proved invaluable in decreas-ing the incidence of stress fracture and increasing the rate of arthro-desis

Fig 3 Fragmentation of the talar dome, as visualized on anteroposterior (A) and lateral

(B)radiographs.

cannulated screws are inserted Occasionally, as a result of frag-mentation, bone loss, or osteo-penia, the bone and joints to be fused are not substantial enough to support these large screws In such situations, the stability of the fusion may be improved by ex-tending the screws across a normal joint into a healthier bone

As an alternative to the use of cannulated screws, a blade plate25

or an intramedullary device has been successfully used in patients with neuroarthropathy (Fig 5) A retrograde intramedullary nail has been extremely useful in these patients, but closed insertion of this nail is not recommended be-cause of the difficulty in achieving adequate reduction without open-ing the joint The insertion tech-nique is important because some-times only one locking screw will fit into the calcaneus if the entry site of the nail is more anterior on the neck of the calcaneus than opti-mal

In the presence of acute or chronic infection, a decision has to

be made whether an amputation or

a lengthy attempt at salvage and reconstruction would be better for the patient Many patients are unable to tolerate the prolonged period of convalescence and

reha-Surgical Techniques

The goal of operative treatment is

to provide maximum stability with

either internal or external fixation,

while facilitating soft-tissue healing

and ultimate arthrodesis The limb

is surgically prepared and draped

above the knee to improve

visual-ization to attain correct alignment

For almost all ankle, tibiotalocal-caneal, tibiocaltibiotalocal-caneal, and pantalar procedures, an extensile lateral approach to the ankle is made after resecting the fibula Bone graft is harvested from the fibula; a small acetabular reamer is directed with pressure onto the fibula, and the cancellous reamings are preserved for later use The reamer is also used to decorticate the lateral tibia and calcaneus where appropriate

The medial side of the ankle is usu-ally exposed by resecting the medial malleolus, although it may be best

to leave it in place as a medial but-tress to improve the stability of internal fixation The talus is pre-served and incorporated into the fusion mass (i.e., ankle, tibiotalocal-caneal, or pantalar arthrodesis), pro-vided there is perfusion to the body and no extensive osteonecrosis If osteonecrosis is present, the head and neck of the talus may be pre-served because they are invariably perfused and will be incorporated into the fusion mass

The avascular and necrotic seg-ments are debrided until bleeding bone is identified The hindfoot is then positioned and temporarily secured with guide pins, and radio-graphs are obtained If the desired position has been attained, large

Fig 4 Fracture of the distal tibia

(arrow-head) after ankle arthrodesis with screw

fixation.

Fig 5 Fragmentation or dislocation of the talus and talonavicular joint, depicted on preoperative AP

(A) and lateral (B) views, is best treated with talectomy Postoperative lateral (C) and oblique (D)

views illustrate use of a blade plate, supplemented by local allograft bone, for arthrodesis.

D

bilitation essential to recovery from

reconstructive surgery; for them,

amputation may be the better

choice For those who will

under-go a salvage or reconstruction

attempt, a staged process is

ad-vised, gaining initial stabilization

with a ring fixator, usually

fol-lowed by rigid internal fixation

with cannulated screws once the

infection is under control

In the absence of infection, an

external fixator can be used to

sup-plement tenuous internal fixation

A standard construct includes

three tibial 5-mm half-pins (two in

line on a single block and one at 45

degrees to them) proximally with

an anterior half-ring A 1.8-mm

wire is placed in the calcaneus

from posteromedial to

antero-lateral, attached to a posterior

half-ring, and tensioned Another

1.8-mm wire is then placed in line

with the ring from posterolateral to

anteromedial, taking care to avoid

the neurovascular bundle, and is

tensioned The construct is

sup-plemented with two threaded

5-mm half-pins introduced into the

posterior calcaneus at

approxi-mately a 45-degree angle to each

other The construct is completed and compressed with connecting rods

If the fixator is used in conjunc-tion with internal fixaconjunc-tion, it is left

in place for 2 to 3 months until there is soft-tissue stability, as indi-cated by decreased swelling and absence of wound breakdown or erythema If the fixator is to be used as the definitive form of stabi-lization, it should remain in place until bone stability is present (usu-ally 4 to 6 months)

Summary

Neuroarthropathy is a disabling disease for the patient and a chal-lenging problem for the ortho-paedic surgeon Not only is the diagnosis of acute disease often delayed, but the management of all stages requires intensive and pro-longed care with considerable at-tention to detail and the coordina-tion of a sizable team The problem

is frequently exacerbated by indif-ference to the disease process on the part of the patient Untreated, the disease progresses to gross

instability, loss of mobility, recur-rent ulceration, and sepsis Treat-ment is aimed at creating or main-taining a stable, biomechanically sound foot that can be accommo-dated in a shoe and that has no osseous protuberances (which might cause recurrent ulceration)

In most cases, this can be achieved with nonoperative measures; major reconstructive surgery is only occa-sionally needed

Closed management of neuro-arthropathy with the use of such modalities as a total-contact cast or

a brace is effective for approxi-mately 75% of patients with stage I

or stage II disease Reconstructive surgery is challenging and should not be contemplated unless an experienced team is available to the surgeon Exostectomy for stage III midfoot ulcers reliably heals the ulcer and permits a return to more normal footwear.21 Operative cor-rection and salvage result in

stabili-ty in 93% of the patients who pre-sent with severe deformity.12 Re-construction as an alternative to amputation remains the preferred method of treatment for selected patients

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