Diabetic Foot and Ankle Disorders

William P. Grant, DPMInstructor Department of

Surgery EVMS

April 1, 2011

Podiatry fhe Primary Physician

DIABETES PREVALENCE

• In the United States total 15.7 million or 5.9% of the population

• Diabetes is the 6th leading cause of death in the US

• 15% of diabetics will experience a foot ulcer.

• 14 to 24% diabetics with foot ulcer will require an amputation

• More than 50% of all non-traumatic below knee amputation occur in diabetics

• 86,000 BKA amputations are performed a year

COMPLICATIONS OF DIABETES

• Heart disease, CVA, PVD,CAD: diabetics are at a risk 2-4 times higher than non-diabetics.

• Kidney Disease: diabetes is the leading cause of new cases of end-stage renal disease (40% of new cases)

• Blindness: 12,000-24,000 people lose their sight due to diabetes each year

• Peripheral Neuropathy: 60-70% of diabetics have mild to severe forms of nerve damage

Contralateral amputation in 3-5 years (51%)Institutionalization (25%)Early death – within 3 years

Complications Following First Amputations

Leading cause of hospitalization for diabetic admissions59.6 hospitalizations per 10,000 patients per yearUp to 25% of all diabetic admissions in U.S. and Britain

Foot Complications and Hospitalizations

Poor glycemic control

- HgA1C > 7

Duration of diabetes > 10 years

Male gender

Impaired visual acuity

Loss of protective sensation (neuropathy)

History of ulceration/amputation

Increased plantar pressure

Peripheral Vascular Disease

Risk Factors for Foot Ulceration

Dyshydrosisanhydrosis

Abnormal Wound Healing

- TCPO2

- Bacterial Load

- Malnutrition

- Immune Function

Other Contributing Factors

Shear Stress

Static Deformity

Claw Toes

Soft tissue

contracture

Gait abnormality

Abnormal Mechanical Environment

Overuse

Brand, Jhass; 1991 :

“repetitive stress applied to sensate rat fore paw led to blistering in one week and ulceration in 10 days”

Abnormal Mechanical Environment

Vascular Exam

•Pedal Pulses

•Venous Filling time

•Elevation / Dependency

•Temperature / digital Hair

•CFT / ABI

•Doppler Ultrasound

Pedal Pulses

Pedal Systolic Pressure

Arm Systolic Pressure

= ABI

Ankle / Brachial Index

≥ .9* No Arterial Occlusion.6 – .8 Intermittent Claudication

.4 – .6 Associated With Rest Pain

< .4 Severe Ischemia AssociatedWith Ulcers and Gangrene

* ABI > 1 may indicate calcified vessel disease which is non-compressible and may falsely elevate the ABI

The Biomedix internet PVL

Neurological Exam

•Sharp vs. Dull

•Filament Test

•Vibratory Sensation

•Muscle Strength / Reflexes

Wagner Classification

Grade 0: Pre-ulcerative

Grade 1: Superficial Ulcer

Grade 2: Full-thickness Ulcer

Grade 3: Abscess/Osteomyelitis

Grade 4: Gangrene Toes/Forefoot

Grade 5: Gangrene Whole Foot

1 → 2 1 → 0

Grade 3 Deep Abscess or Osteomyelitis

Grade 3Deep Abscess in Osteomyelitis

•Appearance

•Exudate

•General Health

•Radiographs

•Laboratory Test

•CBC•Sed Rate•CRP•Deep

Cultures•Bone Biopsy

Grade 4Gangrene of the Toes or Forefoot

Grade 5

• Physics of abnormal foot structure during gait with diabetic neuropathy results in 60% of diabetic foot ulcerations

Biomechanics and Diabetes

Normal anatomy provides stable digits and metatarsal heads against Reactive ground forces during gait

• Loss of Stability by Interossei and LumbricaleIntrinsic Muscles of the Foot Results in:A. Overpowering by the flexor tendons during push off with clawing of the toesB. Resultant contracture at the metatarsophalangealjoints displacing the metatarsal heads downward

The Intrinsic Minus Foot

• Digital ulcerations• Ulceration beneath the ball of the foot• Cavus deformity (high in-step)• The etiology is the intersection of neuropathy and

abnormal structure

Intrinsic Minus Foot

Abnormal Structure Results In Abnormal Pressure on the Foot

Trans Metatarsal Stump Ulcer frequently an indication for BKA

Stump ulceration Ulceration resolved with TAL

• Inability to dorsiflex the foot above 0o

•Compensation usually occurs by pronation at midtarsal joint

•Leads to pes planus foot type

•Abduction of forefoot

•Eversion of STJ

•Unlocking of MTJ

Equinus

•In neuropathic diabetics, AGEs may produce an equinus deformity of the foot and ankle whose compensation is markedly more severe than pronation

•1. Diabetic forefoot ulcerations

•2. Distal stump ulcers

•3. Neuropathic joint disease

Equinus con’t

Achilles tendon lengthening rebalances the imbalance

Achilles tendon isolated for Z-plasty lengthening

Before & After Tendo Achilles Lengthening

Forefoot ulceration Forefoot ulceration resolved with TAL

Charcot Neuroarthropathy

Seen with increasing frequency in diabetic neuropathsFrequently recommended for BKA

•Etiology still obscure (vascular and microtrauma explanations)

Alternative Explanations of Charcot Foot

• Advanced Glycation End-Products: with sustained high glucose concentration a chemical reaction occurs between free amino groups of structural proteins and glucose (AGEs)

• Biomechanical: AGEs may affect the structural integrity of ligaments and the function of tendons resulting in failure of foot integrity

Midfoot stability relies on ligaments which stabilize the joints from reactive gravity and achilles tendon pull

In Charcot, Tendons are contracted, ligaments are weakened, eventually, the foot collapses

In Charcot, Tendons are contracted, ligaments are weakened, eventually, the foot collapses

Achilles Tendon Pathology

•Changes in ultra-structure of Achilles Tendon in control vs. Charcot patients

•Only seen in electron microscopy

•“Electron Microscopic Investigation of the Effects of Diabetes Mellitus on the Achilles Tendon”

» WP Grant, et al, J. Foot &Ankle Surg., Vol. 36 No.4

• Aligned parallel collagen fibrils

• No extensive foci of fibrillar disruption

Normal Tendon vs Charcot Achilles Tendon

• Disruption of Collagen Fibrils

• Irregular appearance compared to normal tendon

• Evidence of Glycation of tendon

Approach to Charcot Disease

• 1. Indications for surgery– Infection including osteomyelitis– Non-healing ulcers– Pain– Walking intolerance– Instability– Progression of disease– Persistent and unremitting edema– Alternative to below knee amputation

Our Systematic Surgical Approach Based on 4 Principals to Charcot Reconstruction

• Foot reconstruction including:1. Tendon Achilles lengthening2. Internal Fixation (beaming) for stability3. Midfoot/hindoot realignment fusion using

autologous Growth FactorsFusion site selected by unstable level of anatomic deformity Goal is normal anatomic alignment

Meary’s angleCalcaneal inclination angle

4. Application of External Fixation for compression

Achilles Z-Plasty

Structural realignment of complex deformity

K-wire osteotomy guides

Lateral Column Beaming

Beaming the Medial Column

External Fixation

6 months post op

Planter grade foot

Fits standard footgear

Report Of 50 Consecutive Charcot Diabetic Salvage ProceduresJanuary 2000-may 2003

DISTRIBUTION OF PROCEDURESSOLID FUSIONS

14 Ankle/Tibiocalcaneal Fusion 43%

13 Triple Arthrodesis 85%

18 Midfoot (Midtarsal) 72%

5 Lisfranc’s 83%

TOTAL OF 50 CASES: utilizing this systematic approach

RESULTS: COMPLICATIONS:

36 Solid Fusion 72% 13 Pin Tract Infection 26%

Psedoarthrosis 9 Dehiscence 18%

8 Stable 12% 8 Osteo/MRSA 16%

1 Unstable 2% 1 DVT 4%

1 Not Know 4%

2 Amputation 4%

2 Frame in Place 4%

BONE STIMULATOR: TOTAL OF 37 CHARCOT CASES HAD BONE STIMULATOR

Results with Internal & External Fixation

Discussion

This retrospective study of our standardized protocol for reconstruction showed:

• Low rate of limb amputation

• Improved quality of life for those patients treated with surgical realignment

• In our study all patients surveyed expressed satisfaction and long term stable functional lower extremity.

• All but one maintained or regained ability to walk

• All patients able to use diabetic or standard shoe gear

• No complication of ulceration

Conclusion

Sometimes your only foot is a Charcot Reconstructed Foot

Thank you for your

attention!