Lecture 2: Orthotic and Prosthetic Considerations for Diabetes

Why Are Feet So Important?

1. Many patients receive a diagnosis of diabetes when they present a nonhealing foot ulcer

2. The mortality rate after amputation is 50% within 3 to 5 years

3. The rate of contralateral amputation is 50% within 4 years

4. 90% eventually lose Protective Sensation

5. 15% of all diabetics will develop a foot ulcer

6. Foot problems account for more hospital admissions of diabetic patients than any other long term complication

7. Studies show that up to 50% of all amputations and foot ulcers can be prevented with effective identification and patient education

8. Amputation rates have not decreased in the past 20 years despite advances in wound and foot care

Peripheral Neuropathy

(sensory, motor, autonomic, cause)

Sensory

• Lack of pain and pressure sensations

Motor

• Loss of intrinsic muscles

  • Results in claw toes and foot drop

Autonomic

• Decreased sweat and oil production

  • Results in dry, brittle skin

Diabetes is a leading cause of Peripheral Neuropathy

Ulcers causes

1. Ischemic Necrosis

   • Low pressure over a long period resulting in tissue death

2. Trauma

   • High pressures, caused by heat, chemicals, foreign objects

3. Inflammation

   Repetitive moderate pressures, weakens tissues and leads to callus formation

4. Osteomyelitis (or other infection)

Ulcers Prevalence Patterns

Highest incidence of ulceration occurs at sites of previous ulcers.

71% of ulcers occur on the forefoot

Most Common

• 3rd metatarsal head

• Great toe

• 1st metatarsal head

• 5th metatarsal head

Wagner Ulcer Classification System

describes the depth of the ulcer, the presence of osteomyelitis or gangrene, and the extent of tissue necrosis

Foot Lesion Prevention

• Patient Education

• Daily Foot Inspection

• Proper Footwear

Prevention of an initial or subsequent foot lesion is crucial to avoiding amputation.

Patient Education Do’s and Don’ts

1. Never soak feet

2. Dry between toes

3. No lotion, petroluem-ointment between toes

4. No creams with perfume/alcohol

5. Never walk barefoot

6. Don’t wear socks with elastic

7. Have professional trim nails and scrape calluses

Conservative Treatment of Neuropathic Foot Ulcers

Evaluation and Wound care

Off-Loading

Protective Footwear and Orthotics

Footwear for diabetic patients

Soft leather

Extra depth – to accommodate inserts

Length = ½’’- ¼’’ space past longest toe

Width = ball of foot should be in widest part of the shoe, instep should not be taut

No stitching over forefoot

Foot Orthoses for Diabetic Patients

Distribute pressure and reduce forces on areas of potential breakdown

Accommodative

Soft: (pelite®, plastazote®, PPT®, OVA®, Spenco®, etc.)

For ulcer grades 0-2

Unweight prominent areas

Decrease local shear stress

Provide general shock absorption

Charcot Arthropathy

Painless, progressive, degenerative arthropothy caused by underlying neuropathy

Can be single or multiple joints

Clinical Observations

• Limb is painless, swollen, hot, and red

• Unhealed factures seen on x-ray

Leads to changes in shape and stability of affected joints

Neuropathic Walkers

Charcot resistant orthotic walker (CROW)

Custom fabricated

Total contact

• equivalent to total contact cast

Rocker bottom sole

Ankle Foot Orthoses

Compensate for muscle weakness

• Commonly foot drop secondary to Peripheral Neuropathy

Prevent motion

Diabetic Amputation Stats

54,000 diabetes related lower extremity amputations/year

86% preventable with patient education and appropriate footwear

50-84% of lower extremity amputations preceded by a foot ulcer

Diabetes Related Causes of Amputation

Gangrene

Infection

Non-healing ulcer

Gangrene

Dry: loss of nourishment to affected area

• Area is dry, black, ‘mummified’

• Can result in autoamputation

Wet: tissue necrosis caused by excessive moisture

• Area is painful, purple, swollen

• Common with infection

Partial Foot Orthoses

Shoe filler

FO with toe filler

AFO with toe filler

Partial Foot ‘Prosthosis’

Clamshell style AFO with toe filler

• Provides toe lever

• Redistributes pressure proximally, away from the fragile soft tissues of the distal foot and over the large pressure tolerant areas of the anterior leg.

• Fills/supports shoe

Prosthetic Considerations for Diabetic Patients

Total Contact

Minimize shear

Distribute Pressures