The Acute Diabetic Charcot Foot Managed on the Basis of Magnetic Resonance Imaging--a Review of 71 Cases

Background: Acute Charcot foot (ACF) is a skeletal breakdown associated with inflammatory swelling of a foot in patients with pain insensitivity, such as diabetic neuropathy. In ACF stage 0, skeletal pathology (e.g. osseous oedema) is visible on magnetic resonance imaging (MRI), but not on plain radiographs. Continued unprotected walking invariably causes stage 1 (complex cortical fractures). Treatment by total contact cast (TCC) is of limited benefit if X-ray-based. The benefits of MRI-based TCC treatment are unknown.

Aim: To assess the impact of MRI, all cases of ACF diagnosed by MRI between 2000 and 2012 were reviewed.

Method: Audit of medical charts of a single outpatient diabetic foot clinic.

Results: Seventy-one cases (59 patients) were retrieved. Diagnosis of stage 0 (n = 27 cases) and stage 1 (n = 44 cases) was established one and two months (medians) after symptom onset, respectively. Unremarkable radiographs, that were not cross-checked by MRI (n = 13 cases), misled primary care physicians to postpone referral until five months after symptom onset, when cortical fractures had already occurred in 12 cases. Midfoot (Chopart- and Lisfranc-) lesions healed better in stage 0 versus stage 1 (69% versus 7% without deformities, p = 0.0012), while forefoot (metatarsal) lesions healed well in either stage (100% versus 75% without deformities). TCC-treatment lasted four to six months.

Conclusion: Healing of ACF was more efficient in stage 0 than in stage 1. Expeditious MR imaging was indispensable to diagnose stage 0 in a swollen foot of a neuropathic patient, while unremarkable X-rays often led to a missed diagnosis.