Taking into consideration the subacute to chronic nature of the patient’s symptoms and the findings on radiographs and MRI, particularly an isolated coronal split fracture of the lunate and marrow signal abnormality, this likely represents the sequela of  Kienböck’s disease.

This condition occurs due to disrupted blood flow to the lunate. Negative ulnar variance is a risk factor. The lunate fracture/fragmentation may be a consequence of Kienböck’s disease, rather than a cause of it. In particular, this fracture is observed in Lichtman stage IIIC Kienböck's disease.

MRI is considered to have the highest sensitivity and specificity for detecting early Kienböck’s disease. Changes typically expected include low T1 and low T2 signal representing sclerosis, often seen diffusely throughout the lunate. Decreased T1 and increased T2 signal representing edema may be seen in the early stages of the disease.

Case courtesy of Dr. Emad Allam - Assistant Professor of Radiology, Loyola University Medical Center