What is the most appropriate way to assess a diabetic patient with a 2 cm ulcer on the first metatarsal and intact distal pulses?

Plain Radiographs Are the Most Appropriate Initial Assessment

The most appropriate way to assess this diabetic patient with a foot ulcer and intact distal pulses is plain radiographs (X-rays) in two weight-bearing views, NOT duplex ultrasound, angiography, MRA, or CT with contrast. 1, 2

Why Plain Radiographs Come First

• Plain X-rays are the essential first imaging study for any diabetic foot ulcer with suspected infection, detecting osteomyelitis in 50-70% of cases, identifying soft tissue gas, revealing foreign bodies, and demonstrating bone architecture changes including Charcot foot deformities. 1, 2

• Weight-bearing films in two views minimum should be obtained immediately for this patient with a 2 cm ulcer, swelling, and discharge suggesting infection. 1, 2

• X-rays provide the essential baseline information about bone involvement and architecture that guides all subsequent management decisions. 1

Why Advanced Vascular Imaging Is NOT Indicated Here

• Duplex ultrasound, MRA, CT angiography, and conventional angiography are NOT first-line diagnostic tools for initial assessment of diabetic foot infection. 1

• These advanced vascular imaging modalities have specific indications that are NOT met in this case: they are only indicated when there is evidence of significant ischemia such as toe pressure <30 mmHg, TcPO₂ <25 mmHg, ankle pressure <50 mmHg, or ABI <0.5. 1

• This patient has intact distal pulses, which makes severe ischemia unlikely and advanced vascular imaging unnecessary at this stage. 1

Critical Bedside Vascular Assessment Still Required

Despite intact pulses, you must perform formal vascular assessment because:

• Up to 50% of diabetic foot ulcers have concomitant peripheral arterial disease (PAD), and the combination dramatically increases amputation risk. 1, 2

• Perform handheld Doppler evaluation of flow signals from both dorsalis pedis and posterior tibial arteries to assess waveform quality. 1

• Measure ankle-brachial index (ABI), with ABI <0.9 confirming PAD and ABI <0.6 indicating significant ischemia affecting wound healing. 1

Additional Essential Assessment Components

• Use a sterile blunt metal probe to assess ulcer depth and palpate for bone—a positive probe-to-bone test in an infected wound makes osteomyelitis highly probable. 1, 2

• Measure the extent of erythema surrounding the ulcer and check for systemic signs (fever, tachycardia, hypotension). 1, 2

• If plain radiographs are negative but clinical suspicion for osteomyelitis remains high (positive probe-to-bone test), then MRI should be obtained to assess infection extent. 2

Common Pitfall to Avoid

• Never assume adequate perfusion based solely on palpable pulses in diabetic patients—formal objective testing with ABI is required. 1

• Do not delay plain radiographs to pursue advanced vascular imaging first, as X-rays provide essential baseline information about bone involvement. 1