What the radiologist needs to know about Charcot foot

Abstract

SummaryCharcot neuropathic osteoarthropathy (CN) is a progressive disease affecting the bones, joints and soft tissue of the foot and ankle, most commonly associated with diabetic neuropathy. Patients with diabetes complicated by CN have especially high morbidity, frequency of hospitalisation, and therefore, significant utilisation of expensive medical resources. The diagnosis of early CN can be challenging and is based on clinical presentation supported by various imaging modalities. Imaging is important for the detection of early CN and is useful in monitoring progression and complications of the disease. The later stages of CN are potentially devastating for individuals and present an increasing socioeconomic challenge for health systems. The astute radiologist, particularly in the context of a multidisciplinary team, plays a critical role in diagnosis of the primary disease and its complications. This review article aims to outline the key features of CN, emphasising current clinical and radiologic concepts as an aid for the practising radiologist.

The Charcot foot: a pictorial review

“…MRI is the best imaging modality to confirm diagnosis of suspected early active Charcot disease [24]. This may be crucial, since conventional radiographs can appear normal during very early stage of Charcot disease (Eichenholtz stage 0, Fig.…”

“…Bone marrow edema can be present (very common in middle-stage Charcot foot) or absent, depending on disease activity. Especially the involvement of Lisfranc’s joint leads to a typically superior and lateral dislocation of the metatarsal bones leading to a complete collapse of the longitudinal arch [2, 24, 25]. The talus head is typically tilted toward the sole of the foot (Fig.…”

“…MRI has a high diagnostic accuracy in diagnosing osteomyelitis of the foot, with a high sensitivity (77–100%) and a high specificity (80–100%) [24]. MRI has a very high negative predictive value (98%): if there are no signs of osteomyelitis on MRI, osteomyelitis can practically be excluded [28].…”

Charcot Arthropathy of the Foot and Ankle

“…Plain radiographs are the initial imaging modality of choice and may show subtle demineralization and polyarticular changes in the midfoot and flattening of the first metatarsal head. 44 Although plain radiographs have low sensitivity and specificity (<50%) during the early stages of Charcot arthropathy, 13 they are useful in ruling out other pathology. Furthermore, serial imaging allows for longitudinal monitoring of the patient's bone structure and alignment.…”

Correlation of Systemic Inflammatory Markers With Radiographic Stages of Charcot Osteoarthropathy

“…Plain radiographs may be negative for any bone changes in acute COA, and therefore contrast-enhanced magnetic resonance imaging (MRI) is regarded as the gold standard to distinguish COA from osteomyelitis, in particular, in early stages where radiographic changes are sparse. 1,8,16 Commonly, infection is further ruled out when there is no presence or history of foot ulceration and negative systemic signs of infection like fever, leukocytosis, and elevated C-reactive protein level or erythrocyte sedimentation rate. The inflammation process is believed to be local, and systemic inflammation parameters are more likely seen in infection than COA and are often used as a differentiating criteria to exclude infection.…”