summary Diabetic Foot Ulcers are very common lower extremity wounds that occur in diabetics with peripheral neuropathy and are responsible for 85% of lower extremity amputations. Diagnosis is made clinically with presence of a plantar foot ulcer which may probe to bone. MRI studies are useful to assess for presence and extent of osteomyelitis. Treatment depends on ulcer size, ulcer thickness, ulcer location and presence of concomitant infection. Epidemiology Incidence approximately 12% of diabetics have foot ulcers most common medical complication causing diabetics to get medical treatment foot ulcers are responsible for ~85% of lower extremity amputations Risk factors factors associated with decreased healing potential uncontrolled hyperglycemia (Hb A1C > 8.0) inability to offload the affected area poor circulation infection poor nutrition factors associated with increased healing potential serum albumin > 3.0 g/dL total lymphocyte count > 1,500/mm3 Etiology Pathophysiology neuropathy has largest effect on diabetic foot pathology sensory dysfunction leads to lack of protective sensation and is primary risk factor for ulcer development autonomic dysfunction leads to drying of skin due to lack of normal glandular function net effect is increased mechanical and axial stress on skin that is more prone to injury due to drying angiopathy lesser effect than neuropathy >60% of diabetic ulcers have decreased blood flow due to peripheral vascular disease Associated condition infection / osteomyelitis high rates of associated osteomyelitis if bone is able to be probed, or is exposed at the base of the ulcer 67% of ulcers that probe to bone have osteomyelitis organisms usually polymicrobial gram-positive most common pathogens are aerobic gram positive cocci (s. aureus) gram-negative increased gram-negative organisms are found in chronic wounds and wounds recently treated with antibiotics anaerobes obligate anaerobic pathogens with ischemia or gangrene deep cultures and bacterial biopsies help guide management Classification Wagner Classification and Treatment Description Treatment Grade 0 Skin intact but bony deformities lead to "foot at risk" Shoe modifications with serial exams Grade 1 Superficial ulcer Office debridement and contact casting Grade 2 Deeper, full thickness extension Operative formal debridement and contact casting Grade 3 Deep abscess formation or osteomyelitis Operative formal debridement and contact casting Grade 4 Partial Gangrene of forefoot Local vs. larger amputation Grade 5 Extensive Gangrene Amputation Brodsky Depth-Ischemia Classification and Treatment Depth Classification Definition Treatment 0 At risk foot, no ulceration Patient education, accommodative footwear, regular clinical examination 1 Superficial ulceration, not infected Off-loading with total contact cast, walking brace or special footwear 2 Deep ulceration, exposing tendons or joints Surgical debridement, wound care, off-loading, culture-specific antibiotics 3 Extensive ulceration or abscess Debridement or partial amputation, off-loading, culture-specific antibiotics Ischemia A Not ischemic B Ischemia without gangrene Non-invasive vascular testing and vascular reconstruction with angioplasty/bypass C Partial forefoot gangrene Vascular reconstruction and partial foot amputation D Complete gangrene Complete vascular evaluation and major extremity amputation Presentation Symptoms often painless Physical exam depth of ulcer probe for bone presence of infection look for cellulitis, pus check for gangrene assess Achilles tendon tightness Silverskiöld test improved ankle dorsiflexion with knee flexed = gastrocnemius tightness equivalent ankle dorsiflexion with knee flexion and extension = Achilles tightness circulation assess dorsalis pedis and posterior tibialis pulses Studies Transcutaneous oxygen pressures (TcpO2) considered Gold Standard to assess wound healing potential > 30 mm Hg (or 40mmHg depending on review source cited) is a good sign of healing potential ABI's and ischemic index calcification in the arteries can result in inaccurate doppler flow readings calcifications falsely elevate the ABI's due to decreased compliance of the calcified vessels index of > 0.45 and toe pressure >45mm Hg are needed to heal amputation and >60mm Hg to heal an ulcer Imaging Radiographs recommended views AP, lateral, and oblique of foot and ankle MRI best for differentiating abscess from soft tissue swelling difficult to differentiate infection from Charcot arthropathy on MRI Bone scan views obtain with technetium Tc99m, gallium (Ga)67, or indium (In) 111 useful to differentiate between soft tissue infection osteomyelitis Charcot arthropathy Treatment General factors important in deciding a treatment plan include angiopathic vs. neuropathic deep vs. superficial +/- osteomyelitis, antibiotics based on bone biopsy culture sensitivities +/- pyarthrosis Nonoperative shoe modification indications prevention when signs of potential ulcers are present includes deep or wide shoes, custom insoles, rocker bottom soles, etc. of the available shoe only modifications, rocker sole shoes best reduce the plantar pressure on the forefoot medicare will cover modifications and custom shoes/insoles yearly wound care indications first line of treatment goals of wound care and dressings provide moist environment absorb exudate act as a barrier off-load pressure at ulcer total contact casting (TCC) indications gold standard for mechanical relief plantar ulcerations contraindications absolute infection relative marginal arterial supply to affected area patients unable to comply with cast care patients unable to tolerate a cast (cast claustrophobia) outcomes if ulcer recurs, it is typically 3-4 weeks after cast removal Operative Flexor tendon tenotomy indications flexible toe deformities with toe ulceration outcomes high rates of healing if there is no osteomyelitis on presentation surgical debridement, antibiotics, contact casting +/- gastroc recession/TAL indications grade 3 or greater ulcers should undergo I&D with antibiotic treatment before casting outcomes high rates of associated osteomyelitis if bone is able to be probed, or is exposed at the base of the ulcer ostectomy +/- TAL indications bony prominence causing internal pressure technique TAL indicated if tight Achilles several studies have shown TAL to be effective to help heal and prevent recurrence of plantar forefoot ulcers partial calcanectomy +/- TAL indications large heel ulcers with associated calcaneal osteomyelitis outcomes preserves limb length and decreases morbidity compared to higher level amputations Syme amputation indications forefoot gangrene and a palpable posterior tibial artery pulse Keller resection arthroplasty indications IPJ plantar neuropathic ulcer with hypomobile/stiff MTPJ that has failed total contact casting Techniques Total Contact Casting often necessary for up to 4 months TCC followed by Charcot restraint walker then custom shoe pneumatic walking brace alternative to TCC, same principal allows better wound surveillance significant deformity and/or extremely large girth often requires custom pneumatic walkers patient compliance with offloading can be an issue because the pneumatic walker is removable Prognosis Diabetic foot ulceration is considered the most likely predictor of eventual lower extremity amputation in patients with diabetes mellitus