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Idiopathic foot injury in a patient with diabetes
Patient complained of right foot injury and popping sound when walking: What’s your diagnosis?
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A 32-year-old woman was referred to the podiatry specialty clinic with complaint of right foot injury.
The patient related hearing a “pop” while walking. She denied any history of trauma or physical injury and had no pain or difficulty with ambulation. Her past medical history was significant for type 1 diabetes, history of Charcot to the left foot, hypertension and renal failure with ongoing dialysis. Her past surgical history included laser eye surgery to both eyes and placement of chest catheter. Her medication list was extensive.
 Patris Toney |
Lower extremity physical examination revealed palpable pedal pulses to the right foot with absent protective sensation. Skin was intact with notable edema. Subtle deformity of the foot was present, however the patient demonstrated no pain upon palpation or range of motion. Her contralateral foot demonstrated no discernable differences to facilitate clinical comparison. Bilateral radiographic examination revealed destruction to the midfoot joints of both feet (figures 1-3).
 |  |  Source: Patris Toney |
Based upon the presentation and x-rays, what would your diagnosis be?
- Fracture of the midfoot
- Osteomyelitis
- Charcot arthropathy
- Charcot with osteomyelitis
CASE DISCUSSION
The Answer is C.
Given the nature of the injury/incident and no suspicion for osteomyelitis, the patient was diagnosed with Charcot arthropathy of the bilateral feet. Surgical intervention was the planned course of action for the right foot. Upon medical clearance, the patient underwent surgical reconstruction of the right foot. Surgery was minimally invasive and comprised reconstruction using external fixation to create a more stable foot structure (figures 4-6). Her recovery process was uneventful. The postoperative course consisted of immobilization for 10 weeks, followed by removal of the ex-fix and placement initially into a short-leg fiberglass cast followed by cam walker with gradual transition to full weight bearing. The patient regained functionality and was able to ambulate with custom molded brace.
Source: Patris Toney
Clinical presentation, associated findings
Charcot’s arthropathy is a destructive disease of the foot’s bony architecture of a non infective nature, which primarily affects the joints. It is a devastating affliction of insidious onset vastly associated with diseases involving peripheral neuropathy or osseous pathology. Charcot’s arthropathy was first described as neuropathic osteoarthropathy in 1703. Initially associated with syphilitic tabes dorsalis, today, diabetes is touted as the most common condition resulting in Charcot.
At the onset, Charcot typically presents as unilateral swelling of the foot which is often red in appearance, hot and swollen. The affected foot exhibits increased pedal blood flow with palpable bounding pulses with an accompanying increase in temperature. The temperature of the affected foot may reveal an increase from 3 to 7 degrees to 10 to 12 degrees compared to the unaffected foot. Physical examination reveals absent deep tendon reflexes, muscle weakness, decreased monofilament sensation and decreased vibratory sensation consistent with peripheral neuropathy.
In the early or acute phase, patients may display no visible radiographic abnormalities. Even more problematic, the patient typically displays little or no pain or tenderness due to the existing peripheral neuropathy. Furthermore, less than half of patients actually recall possible inciting traumatic events such as an ankle sprain. In severe cases with changes of the bony architecture resulting in bony prominences, ulceration may be present.
In the acute phase, soft tissue edema, joint effusions and intra-articular fracture are the distinguishing features. The second phase of coalescence often depicts absorption of small fragments and fusion of larger fragments to the joint surfaces. This phase is accompanied by decreasing edema, which often marks the end of the acute phase. The third phase, known as the remodeling or chronic phase, demonstrates characteristic healing and new bone formation. At this time, the foot is considered stable. Upon radiographic examination, X-rays may demonstrate destruction of the bony architecture along with joint subluxation, bony fragmentation and/or joint effusion. These radiographic findings are considered to be hallmarks of Charcot. Joint aspirations generally reveal bone chips or fragments within the synovium and is considered characteristic.
Treatment
Treatment entails proper offloading/non-weight bearing during the active acute phase to minimize potentiation of the destructive process. This can be achieved by placing the patient in a short-leg cast, cam boot or special Charcot restraint orthosis walker. Bisphosphonates may also be used to facilitate quiescence and consolidation and to minimize demineralization. Conservative long-term treatment measures include specialized shoe gear, bracing, and custom orthosis/inserts. Surgical treatment, on the other hand, is less straight-forward and is often complex, particularly with regards to candidate selection. When surgical reconstruction is undertaken, surgeons may employ internal fixation, external fixation or both.
To ensure adequate patient care, physicians need to know how to identify Charcot arthropathy. Although the manifestations of Charcot appear to be uniform, they are not characteristic. Thus prompt, correct diagnosis is important in the reduction of improper medical and surgical treatment secondary to misdiagnosis. Also, early recognition and immobilization play a role in effectively diminishing the devastating destruction.
Patris Toney, DPM, MPH, is a Fellow at the Center for Lower Extremity Ambulatory Research, and a Fellow at the National Center for Limb Preservation, Ill.