gms | German Medical Science

Objectives/Interrogation: The etiology of Kienböck's disease is unclear so far. Usually it is described as avascular necrosis of the lunate. Although histological research of the whole Kienböck lunate has been reported, the focus was put on comparing the histological pictures with their correlated MRI images. The authors hypothesize that the progress of Kienböck's disease can be speculated by analyzing different tissue types in different parts of the Kienböck lunates.

Methods: Five lunates from patients with stage III Kienböck's disease and one normal lunate were sampled. They were sectioned, H&E stained, and observed with an Olympus Brightfield microscope. The whole lunate was recorded with the NanoZoomer Digital Pathology system for further analysis.

Results and Conclusions: In the normal lunate, the bone trabeculae had a uniform distribution with fatty marrow filling the interspace between the trabeculae. In Kienböck lunates, the trabeculae fracture and necrosis were located in the central part with massive fibrous granular tissue proliferation. There was also some chondroid metaplasia at the palmar and dorsal ends. The trabeculae of the KD lunates were significantly thicker than in the normal lunates. The necrosis was localized around the fracture sites instead of in the whole lunate. Such focal necrosis is very common in different types of fracture ends. Even in stage III Kienböck lunates, the vessels were quite abundant. There was no sign of avascular necrosis for the whole lunate.

There is neither massive bone necrosis nor obvious avascular sign in our histopathology observations. We suggested that Kienböck's disease should be described as lunate nonunion advanced collapse instead of avascular necrosis.