Diabetic Foot Osteomyelitis APMA National...Diabetic Foot Osteomyelitis (10-50%) (1) Plain film radiographs showing cortical erosion (2) MRI showing bone edema or cloaca (3) Positive

Diabetic Foot Osteomyelitis

• Andrew J. Meyr, DPM

-Clinical Associate Professor,

Temple University School of Podiatric Medicine

-Program Director,

Temple University Hospital Podiatric Surgical

Residency Program

-Podiatric Director,

Temple University Hospital Limb Salvage Center

• July 12, 2018

• 2018 APMA National

• Feynman said: The first principle is that

you must not fool yourself – and you

are the easiest person to fool.

From the Flat Earth Society

Illusion of the Bird-Rabbit

Illusion of the Bird-Rabbit

Foot & Ankle

Surgery

Infectious

Disease

Radiology

General

Surgery

Endocrinology

Internal

Medicine

Wound

Care

Pathology

What does osteomyelitis actually look like?

What does osteomyelitis actually look like?

• Osteomyelitis

– Vs.

• Osteonecrosis

– Vs.

• Osteitis

– Vs.

• Periostitis

– Vs.

• Deep soft tissue infection near

and around bone

Foot & Ankle

Surgery

Infectious

Disease

Radiology

General

Surgery

Endocrinology

Internal

Medicine

Wound

Care

Pathology

“Gold Standard” Diagnostic Test

“Standard Reference” for other Diagnostic Tests

Bone Biopsy

What do I do with a “bone biopsy”?

Bone Biopsy

Histopathology Microbiology

What do I do with a “bone biopsy”?

Bone Biopsy

Histopathology Microbiology

PubMed ID#: 7853630

What do I do with a “bone biopsy”?

Bone Biopsy

Histopathology Microbiology

PubMed ID#: 17259493

What do I do with a “bone biopsy”?

Bone Biopsy

Histopathology Microbiology

PubMed ID#: 17259493

55%: Both positive

11%: Both negative

34% Didn’t Agree

PubMed ID#: 21251855

Microbiologic Assessment of Bone (Bone Culture)

Microbiologic Assessment of Bone (Bone Culture)

• Potential Pitfalls:

– Contiguous

extension leading to

contamination

– Culture swabs generally

misrepresenting the

number and type of

pathogens

– Antibiotics

Microbiologic Assessment of Bone (Bone Culture)

• Potential Pitfalls:

– Contiguous

extension leading to

contamination

– Culture swabs generally

misrepresenting the

number and type of

pathogens

– Antibiotics

PubMed ID#: 16323092

PubMed ID#: 18685049

PubMed ID#: 15209762 90% vs. 65%

49%

22.5%

Microbiologic Assessment of Bone (Bone Culture)

• Potential Pitfalls:

– Contiguous

extension leading to

contamination

– Culture swabs generally

misrepresenting the

number and type of

pathogens

– Antibiotics

• Clinical Solutions:

– Percutaneous approach

through unaffected skin

Microbiologic Assessment of Bone (Bone Culture)

• Potential Pitfalls:

– Contiguous

extension leading to

contamination

– Culture swabs generally

misrepresenting the

number and type of

pathogens

– Antibiotics

• Clinical Solutions:

– Only obtain culture specimens

through wounds following

complete irrigation & debridement

Microbiologic Assessment of Bone (Bone Culture)

• Potential Pitfalls:

– Contiguous extension

leading to contamination

– Culture swabs

potentially

misrepresenting the

number and type of

pathogens

– Antibiotics

-168 wounds evaluated with culture

and molecular diagnostics.

-Culture: -Molecular:

-17 diff’t bacteria -338 diff’t bacteria

-Max 3/wound -Max 33/wound

-% wound microbiota

PubMed ID#: 22489109

Microbiologic Assessment of Bone (Bone Culture)

• Potential Pitfalls:

– Contiguous extension

leading to contamination

– Culture swabs generally

misrepresenting the

number and type of

pathogens

– Antibiotics

• Clinical Solutions:

–Antibiotics?

Histopathologic Assessment of Bone(Bone Path)

Histopathologic Assessment of Bone(Bone Path)

• Potential Pitfalls:

– Lack of standardization

with respect to:

• Histopathologic

definition or

classification of

osteomyelitis

• Pathologist training

and personal

experience

• “Test the Testers”– Retrospective analysis of 39

specimens of bone taken from

consecutive diabetic patients in

which the diagnosis of

osteomyelitis was in question.

– 4 pathologists from individually

analyzed the specimens and

only told that it was a

“specimen of bone taken from a

diabetic patient to evaluate for

osteomyelitis”.

Arrive at 1 of 3 potential

diagnoses:

• No evidence of

osteomyelitis,

• No definitive findings

of osteomyelitis, but

cannot rule it out, OR

• Findings consistent

with osteomyelitis

Pubmed ID#: 21907594

• Results:

–33% (13/39): • Complete agreement between pathologists

with respect to primary diagnosis

– 41% (16/39):• Clinically significant disagreement between

pathologists with respect to primary diagnosis

Pubmed ID#: 21907594

• Results:

–Kappa Coefficient: 0.31

• 0 = Poor agreement

• 0.01-0.20 = Slight agreement

• 0.21-0.40 = Fair agreement

• 0.41-0.60 = Moderate agreement

• 0.61-0.80 = Substantial agreement

• 0.81-1.0 = Almost perfect agreement

Pubmed ID#: 21907594

Histopathologic Assessment of Bone(Bone Path)

Histopathologic Assessment of Bone(Bone Path)

Pubmed ID#: 23328849

Lymphocytes, plasma cells

and PMNs

What do I do with a “bone biopsy”?

Bone Biopsy

Histopathology Microbiology

Pubmed ID#: 18442163

Definite (beyond reasonable doubt): >90%

Probable (more likely than not): 51-90%

Possible (less rather than more likely): 10-50%

Unlikely: <10%

“Definite” Diagnostic Criteria for

Diabetic Foot Osteomyelitis (>90%)

(1) Bone sample with positive culture AND

positive histology

(2) Purulence in bone found at surgery

(3) Atraumatically detached bone fragment

removed from ulcer by pod/surgeon

(4) Intraosseous abscess found on MRI

Pubmed ID#: 18442163

“Probable” Diagnostic Criteria for

Diabetic Foot Osteomyelitis (51-90%)

(1)Visible cancellous bone in an ulcer

(2)MRI showing bone edema with other signs of

osteomyelitis

(3)Bone sample with positive culture, but

negative histology

(4)Bone sample with positive histology, but

negative culture

-Any two of these bump you up into “definite”

Pubmed ID#: 18442163

What does osteomyelitis actually look like?

What does osteomyelitis actually look like?

What does osteomyelitis actually look like?

What does osteomyelitis actually look like?

What does osteomyelitis actually look like?

What does osteomyelitis actually look like?

What does osteomyelitis actually look like?

“Possible” Diagnostic Criteria for

Diabetic Foot Osteomyelitis (10-50%)(1) Plain film radiographs showing cortical erosion

(2) MRI showing bone edema or cloaca

(3) Positive probe to bone test/Visible cortical bone

(4) ESR > 70 mm/hr with no other plausible explanation

(5) Non-healing wound despite adequate offloading and

perfusion > 6 weeks

(6) Ulcer of > 2 weeks duration with clinical evidence

of infection

-Any two of these bump you up into “probable”

Pubmed ID#: 18442163

“Unlikely” Diagnostic Criteria for

Diabetic Foot Osteomyelitis (<10%)

(1)No s/s of inflammation AND normal plain

film radiographs AND ulcer present for < 2

weeks AND superficial ulceration

(2)Normal MRI

(3)Normal bone scan

Pubmed ID#: 18442163

Pubmed ID#: 18442163

Definite (beyond reasonable doubt): >90%

Probable (more likely than not): 51-90%

Possible (less rather than more likely): 10-50%

Unlikely: <10%

Level of Agreement with a Multitest Approach to the

Diagnosis of Diabetic Foot Ostetomyelitis

There are multiple ways to assess the

same exact set of information.

Bone biopsy likely remains our best

diagnostic tool, but both the

histopathologic and microbiologic

evaluations are far from perfect.

Infection is first and foremost a

clinical diagnosis and your eyes,

nose, hands and brain will likely

provide you with the most

information if you trust them.

Take Home Points

• Please do not hesitate to contact

Andy if there is anything at all

that he can do for you:

[email protected]

Hockney’s Mount Fuji and Flowers

[email protected]

Questions?

T E A Ex AV