Characteristic features and natural evolution of Kienböck's disease: five years' results of a prospective case series and retrospective case series of 106 patients.

Objectives: Scientific databases index numerous references related to the treatment of Kienböck's disease; yet little is known about the nature of the disease and its pathognomonic features. This study provides a cross-sectional analysis of the pattern and extent of osteonecrosis in a large cohort and a longitudinal analysis to determine the spontaneous disease progression in single patients who have not had surgical management until fragmentation of the lunate.

Methods: In a prospective case series, the pattern and extent of osteonecrosis were correlated with the duration of symptoms in all patients with Kienböck's disease confirmed using high-resolution 3-T magnetic resonance imaging (MRI) and ultra-thin section computed tomographic (CT) scan since 2009. Furthermore, a retrospective consecutive case series study was conducted to determine the rate of spontaneous evolution in all consecutive patients treated conservatively in our university hospital since 1990.

Results: Among the 35 consecutive patients with Kienböck's disease diagnosed in high-resolution 3-T MRI and ultra-thin section CT, 46% (16/35) presented degeneration of lunate cartilage on CT scan in the first 12 months following the onset of symptoms. Median wrist pain duration of patients presenting a fracture of the lunate was 14 months. Thirty-one percent (11/35) of the patients had arthritis of the lunate, yet no fractures at the time of examination. Of 106 consecutive patients with Kienböck's disease and complete records, who did not have surgical intervention until fragmentation of the lunate, three cases were identified with well-documented spontaneous courses from apparently intact lunate morphology until fragmentation within 6 months.

Conclusions: Kienböck's disease progresses substantially faster than previously described and, contrary to current classifications, the articular cartilage of the lunate degenerates in early stages.

Level Of Evidence: Diagnostic accuracy, Level IV.