Case Study: Healing A Chronic Wound In A Patient With Charcot Foot And PAD

Author(s): 
Stephanie C. Wu, DPM, MSc

   In regard to the vascular examination, capillary fill time was less than three seconds for all the toes. I noted mild non-pitting edema on the ankle bilaterally. The skin temperature was warm to cool, proximal to distal bilaterally on the lower extremity. The right foot temperature was 4ºF higher than the left foot. The patient’s dorsalis pedis and posterior tibial pulses were non-palpable bilaterally. In terms of the Doppler exam findings, the dorsalis pedis pulse was monophasic bilaterally and the posterior tibial pulse was biphasic bilaterally.

   The ABI of the left extremity was 0.72 and the left lower thigh brachial index was 0.92 with a significant pressure gradient of 53 mmHg between the left lower thigh and left ankle segmental limb pressures. The right extremity ABI was 0.50 and the right lower thigh brachial index was 0.84. There were significant pressure gradients between the right lower thigh, right calf and right ankle segmental pressures of 29 mmHg and 38 mmHg respectively.

   In regard to the dermatological exam, the patient had dry, scaly skin bilaterally on the foot and ankle. There were no interdigital macerations on either foot. The patient had a full thickness ulcer (3 cm x 3.5 cm in diameter) on the plantar right midfoot with a hyperkeratotic rim. There was no probing, tracking or odor. There were also no gross signs or symptoms of infection.

   The neurological examination findings revealed absent protective sensation (0/10) after testing with the Semmes Weinstein 5.07/10 gram monofilament. The patient had diminished vibratory sensation at the level of the bilateral ankle. He had diminished sharp dull sensation at the level of the lower leg bilaterally.    Proprioception was intact to the level of the first metatarsophalangeal joint bilaterally.

   In regard to the musculoskeletal exam, the patient had muscle strength 5/5 for all gross lower extremity muscle groups. Patellar and Achilles reflexes were absent bilaterally. The ankle joint ROM was +8/+12 on the left and +10/+12 on the right. The first MPJ ROM was 36/30 on the left and 36/30 on the right. The first ray ROM was 1/3 on the left and 2/2 on the right. The patient had diminished range of motion about the ankle, subtalar joint and midtarsal joint bilaterally.

   The patient has assisted gait with a wheelchair. He had a significantly flattened longitudinal arch on the right foot and a rectus left foot.

What The Radiographs And Gait Analysis Revealed

Dorsoplantar and lateral radiographs of the right foot (see Figures 1a and 1b) demonstrated collapse of the medial column along with degenerative changes throughout the midfoot area. There was diffuse osteopenia with calcification of blood vessels noted on the right foot. I noted collapse of the lesser tarsus with resulting plantar bony prominence, specifically with the navicular cuneiform joint, the cuneiform metatarsal joints and the metatarsal cuboid joints.

   As revealed by the plantar pressures below (see Figure 2), the gait analysis showed that the heel never touched the ground because of equinus and the equinus and midfoot breakdown resulted synergistically in the midfoot bearing over 80 percent of the total weight in 80 percent of the stance phase of gait.

   This exorbitant pressure in the midfoot area induces inflammation in the plantar skin below the osseous prominence almost immediately. The thermographic image (Figure 3) shows a 5 degree difference between the affected and unaffected foot after a three minute, mildly paced walk.

Comments

We frequently see such patients with diabetes with renal insufficiency and a baseline creatinine well over 2. What is your opinion regarding the approach and management of such patients given that the vascular surgeon may be reluctant to revascularize as the dye load may push the patient to hemodialysis. My background is general surgery and hyperbaric medicine. Although I do perform arterial revascularization and would like to do more, we also routinely get healing of wounds in patients with an ABI of as low as 0.4 (albeit without the benefit of foot reconstruction).

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