MRI tops X-ray for assessment of active Charcot neuro-osteoarthropathy

Charcot neuropathic osteoarthropathy (CNO) is a rare destructive joint disorder initiated by trauma to a neuropathic extremity. It can lead to dislocations and fractures of the foot. The Charcot foot syndrome is a complex complication of diabetes and neuropathy. Its destructive effects on the foot and ankle begin with a cycle of uncontrolled inflammation.

Commonly fractures are diagnosed by simple X-ray methods however the rare neuropathic osteoarthropathy needs a better diagnostic way for its management. Correct diagnosis and treatment of acute Charcot are imperative to decrease permanent foot deformity and allow for a stable and plantigrade foot that is suitable for ambulation.

A new study in Diabetes Care compared X-ray and MRI as diagnostic tests of active CNO in diabetes. The study suggests MRI is a far more superior and reliable in diagnosing CNO in diabetic people. The X-ray imaging yielded normal findings for 79% of the bones that showed evidence of bone marrow edema on MRI.

Researchers compared X-rays and MRI scans of 48 participants were rated for severity of fracture (0 = no fracture, 1 = fracture, 2 = collapse/fragmentation), and for absence/presence of bone marrow edema (BME) on MRI and absence/presence of bone injury on X-ray. The agreement between modalities was assessed with tests for symmetry, marginal homogeneity, and κ-coefficients.

The key findings of the study are

• X-ray underscored MRI in grading fractures in the metatarsals (P = 0.05) and tarsals (P < 0.001) and reported as normal 79% of the bones with BME.

• The agreement between X-ray and MRI for grading severity of fracture was moderate to substantial (κ = 0.53; P < 0.001) and for detecting bone injury, slight to fair (κ = 0.17; P < 0.001).

Researchers concluded that “The significant underperformance of X-ray in the assessment of the hot, swollen foot in diabetes should be considered when confirming or refuting the diagnosis of active CNO.”

Reference: Oliver Artz; Lisa Meacock; David A. Elias;et al Grading Fractures on Foot and Ankle X-rays and MRI Scans in the Active Charcot Foot in Diabetes: How Strong Is the Agreement Between Modalities? Diabetes Care 2023;46(9):1668–1672; https://doi.org/10.2337/dc23-0220.