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Soft Tissue Conditions of the Foot & Ankle

Gary W. Stewart, M.D.

Chief, Division of Foot & Ankle, Atlanta Medical Center

Partner, Resurgens Foot & Ankle Center

Agenda

1. Infections

2. Diabetic ulcers

3. Trauma

4. Mimickers

5. Q&A

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No relevant disclosures

1. Infections

Oke A. Anakwenze, MD, et al

1. Infections contd.

• A common source of morbidity, disability, and potential limb loss• Diagnosis:

• Dependent on good H&P• Pain is early sign of infection Ability to bear weight• Recent trauma, prior infections, changes in activity/footwear are big risks• Must note systemic conditions (Diabetes, PVD, CKD, gout, etc)

• Labs: • All patients get CBC w/diff, ESR, CRP• Hgb A1C and albumin

• Radiographic evaluation is tailored to the findings from the above mentioned work-up• All x-rays should be weight bearing• Suspected osteomyelitis warrants MRI• Probe to Bone = osteomyelitis

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1. Infections contd.

General categories of infection:

1. Skin and nail bed disorders

2. Soft-tissue infection

3. Diabetic foot infections

4. Deep infections

5. Septic Arthritis

1.1 Skin and Nail Bed Disorders

1. Felon• Severely painful, tense, erythematous distal toe• Tx with I&D similar

2. Paronychia• Often caused by trauma to cuticle or nail fold• May progress to subungual abscess• Tx:

• No abscess: Oral Abx, warm water compresses and soaking in Burow solution• Abscess: Winograd procedure

3. Onychomycosis• Usually diagnosed based on clinical appearance• Treatment is cosmetic for immunocompetent hosts Nail debridement and/or

antifungals (oral or topical)

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1.2 Soft-Tissue Infections

1. Cellulitis• Resulting from skin breaches, often in combination with obesity, venous

insufficiency, lymphatic disruption from prior surgery, cracks in the skin• Systemic toxicity is typically absent blood Cx or skin biopsy unnecessary• Tx consists of Abx, unless a discrete, fluctuant collection is present

2. Necrotizing infections• Uncommon but may result in limb loss or death• Two thirds of necrotizing infections present in the lower extremity• Polymicrobial• Once systemic toxicity sets in (hypotension, organ failure, etc.) mortality

approaches 50% to 70%

1.2 Soft-Tissue Infections

Necrotizing infections contd. • Present as severe, constant pain out of proportion• Bullae, skin necrosis, cutaneous anesthesia or

subcutaneous tissue with a wooden-hard feel• LRINEC score may be useful in borderline cases (>6

suspicious, >8 strongly predictive)• Tx consists of early and extensive debridement

• Repeat debridments every 24 to 36hrs until there is no residual evidence of infection

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1.4 Deep Infections (Osteomyelitis)

• Can occur in the presence or absence of skin ulceration• MRI has proved to be superior to other imaging modalities• Tx typically requires a long course of targeted Abx

• Senneville et al showed that bone-culture specific therapy (as opposed to soft-tissue swap culture) was the only factor predicative of successful nonsurgical treatment

• Surgical intervention is dependent on etiology• Necessary for penetrating trauma or open wounds• Life-threatening systemic symptoms or low-demand patients with little

prospect of rehabilitation may undergo amputation

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1.5 Septic Arthritis

• Usually arises from local inoculation or hematogenous spread• The later is more common in children with open physes

• Most commonly in tibiotalar and first MTP joints• Inability to bear weight and severe pain with micromotion are the most important

physical exam findings• ESR and CRP can be used to aid in diagnosis

• WBC count not useful

• MRI is more effective than x-rays, especially to rule out adjacent osteomyelitis• Joint aspiration is diagnostic gold standard ******

• WBC diff counts 50,000 – 100,00 with >75% neutrophil shift is diagnostic

• Tx consists of of I&D followed by Abx• Abx should only be delayed until intraoperative cultures are obtained if immediate surgical

intervention is planned

Algorithm for management of foot and ankle infectionsOke A. Anakwenze, MD, et al

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2. Diabetic Ulcers

2. Diabetic Ulcers contd.

• 18 million Americans (6%) have diabetes• 30% as yet undiagnosed

• 30% of diabetics age >40 have impaired sensation• As a result 10% to 15% will develop a foot infection in their lifetime• Most significant risk factor for subsequent amputation

• Risk factors: • Neuropathy – Lack of protective sensation and autonomic dysregulation• Ischemia – Commonly secondary to atherosclerosis • Microtrauma

2. Diabetic Ulcers contd.

Ulcer development:

• Rocker bottom deformity caused by degeneration & collapse of the normal midfoot arch• Limits mobility

• Atrophy of the intrinsic muscles allows the stronger flexors to draw toes up in clawed position• Creates new or increased pressure points

• Once ulcer is present, poor nutritional status and blood supply creates unfavorable prognosis for wound healing

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2. Diabetic Ulcers contd.

• Infection is not necessarily present or a prerequisite • Osteomyelitis in 10% to 20% of patient with a diabetic ulcer• In the absence of clinical stigmata of infection, there is no evidence to

support routine use of Abx as an adjunct to ulcer healing

• Infection diagnosed by: • Presence of ulcer > 2cm2

• Positive probe to bone test• ESR > 70• Radiographic findings (periosteal thickening, osteolysis, etc.)

• Every patient requires careful vascular examination and work up

2. Diabetic Ulcers contd.

• For plantar ulcerations in direct weight-bearing areas, force patterns must be altered to allow for healing• Total contact casting with debridements every 2-4 weeks• Rocker sole shoes decrease forefoot pressure

• Restoration of arterial blood flow is essential Vascular surgery needs to be involved

• Surgical treatment is indicated for abscesses, extensive bone or joint involvement or soft tissue necrosis

2. Diabetic Ulcers contd.

• Correction of deformities or bony prominences is essential to long-term prevention of recurrence

• Achilles tendon lengthening is effective to alleviate forefoot pressures• Armstrong et al found significant reduction in forefoot dynamic pressure

along plantar surface and significantly increased dorsiflexion

• Heel ulcers are most challenging, often require BKA due to difficulty of attaining soft-tissue coverage

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3. Trauma

3. Trauma contd.

• Soft tissue handling in trauma comes down to perfusion

• Actual arterial injury is a rare cause for impaired perfusion

• Inflammation related swelling is the main culprit responsible for decreased soft tissue perfusion

• Swelling causes double hit:• Increases the intercapillary distance,

expanding the area any one capillary has to perfuse

• Reduces individual capillary perfusion

3. Trauma contd.

• Once the soft tissues are ready for surgery, incisions should be carefully planned to minimize insult to blood supply

• Angiosomes are distinct from dermatomes and can help guide incisions, particularly for pilontype injuries, which often require two approaches• Angiosomes are commonly used to guide flap

selection and is something we can learn from plastic surgeons

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3. Trauma contd.

Things to do when a traumatic injury comes through the door:

• Good history to elicit comorbidities, especially diabetes

• Good vascular exam including pulses, ABI, skin temperature, hair pattern

• Immobilize the zone of injury to minimize inflammation

• Timing of surgery is critical, check for “wrinkle sign”

• Appreciate the vascular anatomy when planning the surgery

• Trauma is one of the few occasions where orthopaedic surgeons have to operate though highly compromised soft tissues respect them

4. Mimickers

4. Mimickers contd.

Most common suspects:

1. Gout

2. Venous stasis dermatitis

3. Tinea pedis

4. Contact dermatitis

5. Spondylosis

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4.1 Gout

• Mostly seen in men from ages 40-60

• Can be associated with septic arthritis and uric acid crystals do not exclude septic arthritis

• Aspirate shows white, toothpaste like tophy

• X-rays may show punched out periarticular erosions with overhanging borders

• Joint aspiration with crystal analysis is diagnostic

4.2 Venous Stasis Dermatitis

• Most common in women over the age of 40

• Due to venous insufficiency and resultant blood pooling and vascular extravasation

• Typically accompanied by pain, itching, hair loss

• May develop ulcerations

4.3 Tinea Pedis

• Commonly known as Athlete’s Foot

• Fungal infection

• More common in young men

• Affects up to 15% of population

• Resultant skin cracks can lead to bacterial superinfection• May spread to toe nails and cause onychomycosis

• Tx with topical and/or or antifungals

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4.4 Contact Dermatitis

• Example of contact dermatitis after Mastisol use

• Usually has architectural shape consistent with offending agent that contacted skin• May match shoe

• Usually irritant or allergic in nature

• Tx with corticosteroids

4.5 Spondylosis

• Dermatomal pain patterns in the foot are often spine related

• Patient history most useful to establish diagnosis

• Lumbar x-rays aid in diagnosis

• The foot is often a window into the whole body

Q & A

Thank you!