Mann’s surgery of the foot and ankle V.2

801 Pages·129.623 MB·English

by  Coughlin M., Saltzman C., Anderson R.

MANN’S SURGERY OF
THE FOOT AND ANKLE
Volume 1
MANN’S SURGERY
OF THE FOOT
AND ANKLE
NINTH EDITION
Michael J. Coughlin, MD
Director, Saint Alphonsus Foot and Ankle Clinic, Boise, Idaho
Clinical Professor, Department of Orthopaedic Surgery
University of California, San Francisco, San Francisco, California
Past-president, American Orthopedic, Foot and Ankle Society
Past-president, International Federation of Foot and Ankle Societies
Charles L. Saltzman, MD
Chairman, Department of Orthopaedics
Louis S. Peery MD Endowed Presidential Professor, University of Utah
University Orthopaedic Center, Salt Lake City, Utah
Past-president, American Orthopaedic Foot and Ankle Society
Vice President, International Federation of Foot and Ankle Societies
Robert B. Anderson, MD
Chief, Foot and Ankle Service
Vice-chair, Department of Orthopaedic Surgery, Carolinas Medical Center
OrthoCarolina Foot and Ankle Institute, Charlotte, North Carolina
Past-president, American Orthopaedic Foot and Ankle Society
1600 John F. Kennedy Blvd.
Ste 1800
Philadelphia, PA 19103-2899
MANN’S SURGERY OF THE FOOT AND ANKLE ISBN: 978-0-323-07242-7
Volume 1 Part Number: 9996074684
Volume 2 Part Number: 9996074749
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Library of Congress Cataloging-in-Publication Data
Mann’s surgery of the foot and ankle / [edited by] Michael J. Coughlin, Charles Saltzman, Robert B.
Anderson.—Ninth edition.
p. ; cm.
Surgery of the foot and ankle
Preceded by Surgery of the foot and ankle / edited by Michael J. Coughlin, Roger A. Mann, Charles
L. Salzmann. 8th ed. c2007.
Includes bibliographical references and index.
ISBN 978-0-323-07242-7 (set : hardcover : alk. paper)
I. Coughlin, Michael J., editor of compilation. II. Saltzman, Charles L., editor of compila-
tion. III. Anderson, Robert B. (Robert Bentley), 1957- editor of compilation. IV. Title: Surgery of
the foot and ankle.
[DNLM: 1. Ankle—surgery. 2. Foot—surgery. 3. Ankle Injuries—surgery. 4. Foot Diseases—
surgery. WE 880]
RD563
617.5’85059—dc23
2013017557
Executive Content Strategist: Dolores Meloni
Content Development Manager: Lucia Gunzel
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Project Manager: Cindy Thoms
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Printed in China
Last digit is the print number: 9 8 7 6 5 4 3 2 1
Preface
In 1959, Henri L. DuVries, MD, published the first edition believe that the principles initially espoused by Drs.
of Surgery of the Foot. This text summarized his 30-year Inman and DuVries and expanded on by Dr. Mann have
personal experience in diagnosing and treating disorders, given me a unique perspective.
deformities, and injuries of the foot and ankle. His book In 1993, Dr. Mann and I collaborated on the sixth
became a classic, but it was also significant because it was edition, which was expanded to a comprehensive two-
written by a physician who originally had obtained his volume text. In 1999, this was revised by us as the seventh
training as a podiatrist and then subsequently became a edition and, in 2005, it was published as a colorized
doctor of medicine. eighth edition, in which we were joined by, Dr. Charles
In 1965, Dr. DuVries expanded the book to include L. Saltzman, as a co-editor.
several other contributors, taking a form that is a model This is a living text and has continued to evolve from
even for the current textbook. Included in this second the initial work of Henri L. DuVries. Much of our ortho-
edition were Verne T. Inman, MD, chairman of the paedic careers have been devoted to working with this
Department of Orthopaedic Surgery at the University of text; Dr. Mann has contributed to or edited all but one
California, San Francisco, and Roger A. Mann, MD, a of the first eight editions, and I have contributed to or
senior resident in orthopaedic surgery. Eight years later, in edited half of the editions. However, change and growth
1973, Dr. Inman succeeded Dr. DuVries as the editor of are important! As of this edition, Dr. Mann has become
the third edition of Surgery of the Foot. Again, with this text, an editor emeritus but has continued to give us his
an expanded objective included discussion of the ankle input and valued advice. To recognize and honor his
joint as well as an in-depth analysis of the biomechanics invaluable contributions to the textbook, we have named
of the foot and ankle. Five years later, in 1978, Dr. Mann this ninth edition Mann’s Surgery of the Foot and Ankle.
became the editor of the fourth edition. Dr. Mann, having Most important, Robert B. Anderson, MD, a past fellow
been a resident under Dr. Inman and having served a fel- of John Gould, MD, joins Dr. Saltzman and me as an
lowship under Dr. DuVries, was presented with a unique editor of this text. Dr. Anderson brings a wealth of clini-
opportunity to blend the special interests of these two cal knowledge and a sports medicine background to
unique clinicians—Dr. Inman’s basic biomechanical this association. Just as Dr. DuVries complemented his
research and Dr. DuVries’ wealth of clinical knowledge. In text by adding Dr. Inman, and Dr. Inman introduced
1986, Dr. Mann edited a revised fifth edition. Dr. Mann, we feel strongly that Dr. Anderson’s addition
In 1978, as Dr. Mann’s first foot and ankle fellow, I will make this a stronger and more well-rounded work.
had the opportunity to be exposed to both his philosophy The ninth edition is also enhanced by the work of many
of patient care and the creativity with which he addressed of our excellent fellows and colleagues from around the
the evaluation and treatment of his patients. His meticu- world who have made substantial sacrifices to contribute
lous surgical technique and comprehensive postoperative to this textbook. In this edition, 25 authors continue
program were coupled with an introspective method of to contribute, but 42 new authors have been added.
assessing the results of specific procedures to delineate the These contributing authors are at the forefront of their
preferred treatment regimen. Dr. Mann’s 45 years in specific area of foot and ankle surgery. Each contributing
private practice, stimulated by more than 75 foot and author has covered a specific topic in a comprehensive
ankle fellows, have complemented my interaction with fashion, which we believe will leave the reader with a
him. In 1999, I initiated my own fellowship program and clear, concise appreciation of the subject. Although this
have learned a great deal from the 15 fellows who I have book is not meant to be encyclopedic in nature, our
trained. I also have frequently reviewed the surgical pro- goal has always been to provide the reader with a method
cedures used in my everyday practice, with the common of evaluating and treating a particular problem. More
goal of defining the strengths of individual procedures as than 40% of the ninth edition has been completely
well as their weaknesses. From the 34 years that I have rewritten by both new and returning contributors, and
been in private practice in Boise, Idaho, I have come to the remaining chapters have been updated.
xiii
Preface
In 1990, Dr. Mann and I published the Video Textbook plantar plate tears and treatment of this complex
of Foot and Ankle Surgery, the second volume of which problem. The chapters on sesamoids, keratotic disorders,
appeared in 1995. This enabled foot and ankle surgeons and toenail abnormalities have all been updated as well.
to view a surgical procedure while simultaneously reading Part III, Nerve Disorders, and Part IV, Miscellaneous,
about the operative technique. Encouraged by the success have been completely updated to cover both acquired and
of this endeavor, the eighth edition of Surgery of the Foot static neurologic disorders; the material about heel pain
and Ankle incorporated, for the first time, 60 edited videos has been rewritten and updated by new authors.
on two DVDs. This unique addition has now become an Part V, Soft Tissue Disorders of the Foot and Ankle,
industry standard. To enhance the current edition, we includes revised chapters on infection, dermatology, and
have retained 45 classic videos narrated by Dr. Mann and soft tissue reconstruction and a completely new chapter
added 75 new videos contributed by us as well as many on tumors of the foot and ankle.
other colleagues. Furthermore, advances in Internet and Part VI, Arthritis, Postural Disorders, and Tendon Dis-
online learning have enhanced the electronic version of orders, has been completely revamped, updating our
the ninth edition textbook and video compilation to current knowledge and treatment of systemic inflamma-
allow viewing on smartphone and tablet devices before tory arthritis, traumatic arthritis, and osteoarthritis. The
performing surgical procedures, affecting both learning chapter on total ankle arthroplasty presents substantial
and improving patient care. changes because of the dramatic developments that have
This new edition has been divided into 10 sections that occurred over the past decade in ankle joint replacement.
have been subdivided into chapters. Specific surgical tech- Revisions of the chapters on pes planus and pes cavus are
niques within the chapters are described and illustrated included. The chapter on arthrodesis of the foot has been
in detail to afford the reader an understanding of the replaced by one on arthritis of the hindfoot and midfoot,
indications for each procedure and insight into the per- containing both assessment and surgical treatment of
formance of the technique. Although many different conditions in this region. The chapter on tendon abnor-
treatment regimens are presented, our goal is to recom- malities has been extensively rewritten to reflect signifi-
mend a specific treatment plan for each pathologic entity. cant technical advances in this area.
Furthermore, some topics are presented in more than one A separate section, Part VII, Diabetes, contains three
section, enabling the reader to appreciate the varying completely updated chapters on diabetes, amputations,
points of view presented by individual contributors. It is and prostheses of the foot and ankle.
our goal to provide the reader with an accurate assess- Part VIII, Sports Medicine, includes a comprehensive
ment of both the attributes and the deficiencies of specific chapter on athletic soft tissue injuries as well as specific
orthopaedic foot and ankle procedures, new and old. In chapters regarding stress fractures and arthroscopy; all
this edition, we present our most up-to-date thinking three chapters have been revised and updated to familiar-
regarding the diagnosis, treatment, and specific surgical ize the reader with this exciting and evolving area of
care of foot and ankle problems. orthopaedic technology.
In Part I, General Considerations, the biomechanics, Pediatrics is covered in Part IX with two chapters: a
examination, and conservative treatment of foot and general pediatric chapter and a separate chapter on con-
ankle problems are addressed. In large part, the initial genital and acquired neurologic disorders, where new
principles advocated by Dr. DuVries, Dr. Inman, and Dr. authors have added significant new information.
Mann, as presented in their early editions, are included Finally, Part X, Trauma, includes six chapters. These
in this portion of the text but have been updated. Anes- chapters, which have been updated and revised, include
thetic techniques have been completely rewritten and discussion of fractures of the distal tibia; ankle; disloca-
have been updated to include popliteal blocks and tions of the foot and ankle; and calcaneus talus, midfoot,
indwelling catheters. Discussions of imaging methods, and forefoot fractures, which are covered in a comprehen-
an integral part of the evaluation process for foot and sive fashion.
ankle disorders, have also been completely rewritten and As Roger Mann stated in the preface of the fifth edition,
include in-depth coverage of magnetic resonance imaging “As medicine continues to progress, the information of
and computed tomography. this textbook will again need to be upgraded. The prin-
In Part II, Forefoot, an extensive analysis of deformi- ciples presented, however, are basic in their approach and
ties of the great toe, along with complications associated will not change significantly over the years.” We believe
with individual hallux valgus procedures, has been com- that the ninth edition of Mann’s Surgery of the Foot and
pletely revised to make the reader aware of primary sur- Ankle will strongly enhance this dynamic and exciting
gical techniques as well as salvage techniques used for field of orthopaedics and will complement the learning
postsurgical complications. Inclusion of newer, popular experience of the resident and fellow-in-training as well
surgical techniques has been added. The chapter on lesser as the practicing surgeon.
toes has been completely rewritten and updated because Michael J. Coughlin, MD
of the vast number of advances made in the area of
xiv
We are proud to dedicate the ninth edition of Surgery of the Foot and Ankle to Roger A.
Mann, MD, and have changed the official name to Mann’s Surgery of the Foot and Ankle.
Dr. Mann served as a mentor and teacher at a time when there were few foot and ankle
fellowships or fellows. He guided the American Orthopaedic Foot and Ankle Society in its
early years and promoted education of residents and surgeons in active practice through
programs at the American Academy of Orthopedic Surgeons and the American Orthopaedic
Foot and Ankle Society meetings. Prolific in his studies and publications, he has introduced
more than 75 fellows to his methods of investigation and surgery, thus truly changing
surgery in America during his time. He took the rather small primer entitled Surgery of
the Foot and changed it to a two-volume color textbook—Surgery of the Foot and Ankle,
with a video supplement—that has become the definitive textbook for foot and ankle
surgery in the world.
His vision and action are proof that one man can truly make a difference, and he has
done that.
xvii
27
Chapter
Diabetes
Jeffrey E. Johnson, Sandra E. Klein, James W. Brodsky
Infection 1443
CHAPTER CONTENTS
Cellulitis 1444
Abscess 1444
BACKGROUND AND HISTORY 1385
Osteomyelitis 1444
PATHOPHYSIOLOGY 1386
Hyperbaric Oxygen 1450
Metabolic Control 1386
Treatment of Charcot Arthropathy 1450
Neuropathy 1386
Pharmacologic Therapy 1455
Angiopathy 1387
Surgical Treatment 1455
Structural Changes 1388
Timing of Operative Treatment 1455
COMMON CLINICAL PROBLEMS ASSOCIATED
Surgical Techniques 1455
WITH DIABETES 1388
Unique Considerations in the Treatment of
Ulceration 1388
Ankle Neuropathic Arthropathy 1459
Classification of Diabetic Foot Ulcerations 1390
Surgical Decision Making for Charcot Ankle 1460
Charcot Neuropathic Arthropathy 1393
Charcot Ankle Arthropathy Associated with
Temporal Staging of Charcot Neuropathic
an Open Wound 1460
Arthropathy 1396
Unstable Ankle Deformity Patterns 1461
Anatomic Classification of Charcot Arthropathy 1396
Multijoint Arthropathy 1462
Skin and Nail Disorders 1399
Ankle Fractures in the Diabetic Patient 1467
Infection 1400
Ankle Fracture Treatment Options and Rationale 1468
DIAGNOSIS 1405
Postoperative Management: Prolong Length
Physical Examination 1405
of Immobilization 1469
Neurologic Evaluation 1406
Amputation 1471
Vascular Evaluation 1407
Radiographic Examination 1409
Plain Radiographs 1409
Magnetic Resonance Imaging 1410
BACKGROUND AND HISTORY
Computed Tomography 1410
Bone Scans and Labeled White Blood Cell Scans 1411 Diabetes mellitus was described in the medical writings
[18F]-2-Fluoro-2-Deoxy-D-Glucose–Positron of fifth century BC Greece, and the name itself is from the
Emission Tomography 1412 Greek (dia, through; bainein, to go; melitos, honey). It was
TREATMENT APPROACHES 1412 diagnosed by the sweet taste of patients’ urine, their exces-
Patient Education 1412 sive thirst, and the agony of their inevitable death.273
Team Approach 1412 Although the method of diagnosis was slightly less crude
Neuropathy 1413 by the beginning of the 20th century, little else changed
Topical Therapies 1413 in the natural history or course of this disease for 2500
Treatment of Motor Neuropathy 1415 years. Only with the discovery of insulin by Banting and
Nerve Release for Treatment of Sensory Best in 1922 did the modern era of diabetes as a nonfatal
Polyneuropathy 1415 chronic disease begin. Since that landmark discovery,
Total-Contact Casting 1417 medicine has unfolded the myriad multisystem complica-
Footwear and Shoe Insoles 1425 tions by which this disease is now well known.
Wound/Ulcer Management 1431 The American Diabetes Association currently estimates
Activity Modification 1432 the population of diabetic patients in the United States is
Local Wound Care 1433 more than 25 million and rising as the average age in the
Surgical Treatment 1433 United States increases, because the incidence of diabetes
Specific Ulcerations and Treatment 1434 increases with age.96 The Centers for Disease Control
Wound Closure and Soft Tissue Reconstruction 1441 and Prevention estimates that over a quarter of these are
1385
Part VII ■ Diabetes
undiagnosed cases.96 Foot problems, especially infections,
are the most common disorder, necessitating hospital
admission. More than 60% of nontraumatic lower limb
amputations occur in patients with diabetes.96
The diabetic foot and its complications are encoun-
tered by practitioners in many different specialties, as well
as by the orthopaedic surgeon, because of its prevalence
in the same patient population who, for example, require
total joint replacement. The complications of diabetes
also affect such ordinary orthopaedic problems as frac-
tures of the foot and ankle.
The incidence of diabetes has increased dramatically
in people older than 40 years, and an estimated 26% of
the population older than age 65 is affected. The cost in
morbidity, mortality, and time lost from work and family
is enormous. The economic impact of diabetic foot prob-
lems and their sequelae on the health care system is
mammoth.15,139,298
A review of diabetic patients in a medical clinic showed Figure 27-1 Insensitivity resulting from neuropathy allowed
a 68% incidence of some form of foot disease. Most this patient to step on a broken nail. The patient did not
problems were mild, with very early changes, such as recognize the injury until a severe infection occurred.
callus formation (51%) and hammer toes (32%); some
were more apparent as sources of eventual injury and
Neuropathy
disease, such as sensory (34%) and autonomic (25%)
neuropathy; however, all represented the early requisites Neuropathy, especially sensory neuropathy, is the preemi-
that can lead to later problems of ulceration and nent source or initiating event of almost all ulcerations
infection.190 and most infections (Fig. 27-1). Peripheral vascular
The severity of the complications of diabetes in the disease often coexists with neuropathy and contributes to
foot is not necessarily related to the severity of the disease poor or delayed healing, but it is seldom the initiating
itself. The majority of complications occur in patients event. Vascular insufficiency causes tissue ischemia and
with type 2 diabetes mellitus (T2DM), who account for can produce gangrene, prevent healing because of mar-
the large majority of the diabetic population. Despite the ginal nutrition of tissue, or even cause ischemic pain.
advances in the field of diabetic foot care, including better However, the loss of protective sensation combined with
control of hyperglycemia, the discovery of a multitude acute trauma, recurrent trauma, repetitive trauma, or even
of new antibiotics, advanced surgical and nonsurgical microtrauma leads to most instances of soft tissue break-
techniques for vascular reconstruction, dissemination of down in the diabetic foot.35,61,125,238
knowledge on the relief of pressure to treat ulcerations, The exact cause of diabetic neuropathy remains to be
and new diagnostic modalities for evaluating tissue oxy- fully elucidated; however, autopsy studies have indicated
genation in the extremities, the treatment of problems of that changes in the vasa nervorum, with resulting isch-
the diabetic foot remains obscure, if not puzzling, to emia to the nerves, are the major pathway. The two theo-
many physicians and surgeons. ries regarding these microvascular changes in the nerves
postulate the accumulation of sorbitol and intraneural
accretion of advanced products of glycosylation. The only
PATHOPHYSIOLOGY current possible treatment involves enzymatic blocking of
the biochemical path toward sorbitol, but the efficacy of
Metabolic Control
this treatment remains unproved.29 For all practical pur-
Diabetes is a metabolic disease resulting from inadequate poses at this time, neuropathy remains an irreversible
insulin secretion, decreased responsiveness to insulin, or condition that tends to progress gradually, and it lies at
both. The hyperglycemic state experienced in diabetes is the heart of most foot disease in the diabetic patient.379
considered multifactorial, but most specialists agree that Risk of developing neuropathy is associated with poorer
the long-term control of blood glucose levels reduces a glucose control, age, and height.6,298
patient’s risk for the known long-term complications of Brand and Ebner wrote a pioneering paper in 1969
diabetes, such as vascular disease, nephropathy, retinopa- describing the importance of pressure in the develop-
thy, and neuropathy.198 Careful control of blood glucose ment of insensitive hands and feet. This study called
levels is critical for prevention as well as treatment of for objective methodology to quantify pressure and her-
diabetic foot pathology. All diabetic patients should be alded the development of this area of investigation.64
followed closely by a primary care physician or endocri- Research using optically based52,53,57,135,149 and electroni-
nologist experienced in the treatment of diabetes. cally based92,155 pressure measurement systems have
1386
Diabetes ■ Chapter 27
demonstrated abnormal, increased pressures under the
diabetic foot that have been postulated for so long but
could not be measured or quantified before these devel-
opments.18 One early study57 used the optical pedobaro-
graph to examine patients with neuropathy for abnormal
plantar pressures, defined as pressures greater than
10 kg/cm2. The same patients, when examined 3 years
later, showed that some of these pressure areas resolved,
whereas new ones appeared in others; 5 of 6 patients in
the group of 39 who developed ulcers developed them
in the areas identified previously as locations for abnor-
mal pressure. Figure 27-2 Dry, scaly skin associated with autonomic
In a study by the same group,83 14 of 44 patients component of diabetic peripheral neuropathy.
thought clinically not to have neuropathy were discovered
to have abnormal plantar pressures.57 When tested for
vibratory sensation and sensory nerve conduction, these
patients showed significantly decreased function, which
suggests that the pathologic pressures that lead to ulcer-
ation can occur in conjunction with neuropathy but at a
point before the neuropathy itself is apparent. A study
comparing diabetic patients who have a history of ulcer-
ations with diabetic controls without such a history
revealed that both the severity of neuropathy and the
peak pressures under the foot were greater in the group
who had ulcerations.360
A number of studies have examined the effect of
peripheral neuropathy on postural stability and gait. Figure 27-3 Clawing of toes associated with motor
Studies examined both a subjective history of falling component of diabetic peripheral neuropathy. Hyperextended
as well as biomechanical function in standing and in metatarsophalangeal joint increases pressure under
walking.89 Peripheral neuropathy, regardless of the cause, metatarsal heads, and flexed proximal interphalangeal joint
increases risk of ulceration on dorsum of toes.
was demonstrated to be associated with an increased risk
of falling.323 The abnormalities appear greater in standing
and balance than in gait.91,351 Clinically, it is important to changes predispose to ulcerations on the dorsum of the
keep in mind that balance is a function of three factors: digits. The claw toe deformity contributes to a second area
proprioception, which is affected by peripheral neuropa- of ulceration as well because it increases pressure beneath
thy in the lower extremities; vision; and the vestibular the metatarsal head as the pressure of the base of the
system. The first two factors can be damaged by complica- hyperextended proximal phalanx pushes down on
tions of diabetes, namely, peripheral neuropathy and reti- the metatarsal head through its intact but contracted
nopathy. Therefore the physician should be aware of the tendons.150 Magnetic resonance imaging (MRI) in neuro-
risk of balance issues when both of these complications pathic patients has demonstrated extensive atrophy of the
are present. intrinsic foot muscles, which precedes clinical hammer
Autonomic neuropathy produces a loss of normal sweat- toe deformity.80 Mononeuropathy, most often affecting
ing in the skin of the foot. This leads to stiff, dry, scaly the peroneal nerve, can produce unilateral or bilateral
skin that cracks easily because of its inflexible quality. footdrop, which is often unrecognized until the patient
Cracks in thickened skin, and especially in the stiff cal- has developed a fixed equinus deformity. The equinus
luses on the sole, propagate into and through the dermis position increases pressure on the forefoot and thus con-
to open pathways for infection (Fig. 27-2). Loss of normal tributes to ulceration of the forefoot or the distal end of
skin temperature regulation is also a result of autonomic a partial foot amputation.
neuropathy. A blunted response in diabetic extremities to
increased temperature demonstrates this autosympathec-
Angiopathy
tomy effect and is thought to contribute to infection and
injury.158 Autonomic neuropathy, as measured by blood Arteriosclerotic disease is more common and more severe
flow variability and vasoconstrictor response, was demon- in diabetic than in nondiabetic patients.275 The calcifica-
strated to be associated with foot ulceration in diabetic tion of atherosclerotic plaques in nondiabetic patients is
patients with neuropathy.162 patchy and occurs within the intimal layer of the vessel. In
Motor neuropathy is expressed as a loss of function and contrast, the characteristic calcification in diabetic arteries
contracture of the intrinsic muscles of the foot that leads is circumferential and diffusely distributed along the
to the classic claw toe deformities (Fig. 27-3). These vessel length and occurs within the tunica media of the
1387
Part VII ■ Diabetes
arteries. This produces the typical lead pipe appearance of hardness remain to be defined with regard to their clinical
calcified arteries on radiographs and can be seen in large relevance.121,229,286 The thickness of plantar tissue has been
and small vessels alike. It is often visible out to the vessels suggested to be related to the magnitude of peak plantar
of the midfoot or even the toes. These calcified vessels are pressures in diabetic patients,4,166 although in one study,
noncompliant and brittle. They produce artifactual eleva- the soft tissue thickness was not greater in control subjects
tion of Doppler pressure measurements in the lower than in diabetic subjects.324
extremities and make vascular reconstruction problematic Recent studies by Abboud et al3 on muscle dysfunction
at the time of anastomosis of a saphenous vein bypass provide fascinating new information with regard to a
graft into this stiff tissue. No evidence, however, indicates dynamic component of increased foot pressure leading to
that calcification per se, rather than occlusion, is directly ulceration. Diabetic patients were shown to have a greater
responsible for decreased perfusion in the foot.101 period of contact pressure and a measurable delay in ini-
Proximal occlusive vascular disease does occur in dia- tiation of contraction of the tibialis anterior. The authors
betic patients in the aortic, iliac, and femoral vessels, and postulated that late firing of the ankle dorsiflexors resulted
vascular reconstruction of these proximal lesions is often in reduced control of foot contact after heel strike.3
required to salvage foot lesions. It is critical to remember New study methodology continues to be consistent
that the diabetic patient with a dysvascular lower limb may with the basic clinical principle that ulceration requires
have arterial disease in the proximal and distal parts of the both pressure and neuropathy. Foot pressures alone do
arterial tree. However, the vascular involvement in the not predict foot ulcerations.119,243
distal part of the lower extremity of the diabetic patient is Another mechanical factor that has been investigated
unusual and different from the nondiabetic patient’s concerns structural changes within the foot itself. Authors
because of the diffuse pattern of involvement that occurs have shown a decreased plantar muscle thickness consis-
below the popliteal artery trifurcation. The widespread, tent with motor neuropathy, as well as changes in meta-
multisegmental occlusion of these small arteries usually tarsophalangeal (MTP) joint extension and increased MTP
requires dilation or bypass procedures down to the level of joint arthropathy that may be contributing to the develop-
the ankle. The procedures are done to whichever, if any, of ment of ulcerations. These measurements appear to repre-
the anterior tibial, posterior tibial, or peroneal arteries is sent a structural measurement for the effects of autonomic
patent and has adequate runoff at the ankle level. Further- and motor neuropathy described earlier.324 However, the
more, the diabetic limb is unusual because of the common relationship of static foot structure to plantar pressure and
involvement of the major arteries of the foot by the athero- ulceration formation is yet to be fully defined.90
sclerotic process, unlike in the nondiabetic extremity. Biochemical changes in the periarticular tissues, espe-
Occlusive changes may be variable at different levels of the cially of the small joints (e.g., in the hand and foot), have
limb, with diminished toe pressures in a foot that has a been noted to produce thickened skin, diminished range
reasonable dorsalis pedis or posterior tibial pulse. of motion, and joint contractures in diabetic patients
Much has been made of so-called small-vessel disease (Fig 27-4).231 Recent studies have demonstrated similar
or microvascular changes of the diabetic foot. However, changes producing abnormal joint mechanics in the feet
recent studies question the reality of small-vessel disease and ankle.136,319 Subtalar motion is decreased in diabetic
at the subarteriolar level. The occlusive nature of this patients and, to a greater degree, in those with a previous
supposed entity in the absence of large-vessel occlusion history of ulceration than in those who have not had foot
remains undocumented and unproved. In addition, ade- ulcers.126
quate correlation has not been proved between the known It is not possible to state that this represents a cause-
changes in capillary permeability and basement mem- and-effect relationship between joint stiffness and the
brane thickening in the diabetic foot and the physiologic ulcerations. Some suggest that the limited joint mobility
events of gangrene and infection.262 Actual measurement syndrome itself leads to increased plantar pressures.150,282,326
of blood flow in diabetic patients with supposed small- One study found an association with Charcot arthropa-
vessel disease failed to show a difference when compared thy, although it was unclear whether the limited joint
with control subjects with and without peripheral neu- mobility syndrome was an effect rather than a cause.104
ropathy from other causes; this led the investigators to
conclude that toe lesions were caused by changes of neu- COMMON CLINICAL PROBLEMS ASSOCIATED
ropathy and that the lesion of “microvascular disease” WITH DIABETES
remains unproved.196
Ulceration
Ulcerations of the diabetic foot are the single most
Structural Changes
common problem for which medical assistance is sought.
Stiffness and callous formation within the skin have also The economic burden of diabetic ulcers is significant even
been found to be factors associated with ulceration. in a multidisciplinary clinic specifically designed for effi-
Whether the callous formation represents a true indepen- cient care of diabetic patients.15,328 The lifetime risk of
dent variable or is another expression of pressure is not developing a diabetic foot ulcer has been reported at
proved. Measures of plantar tissue stiffness or plantar skin 15%, with an annual incidence of 2%.59,355
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