Microstructural study of the lunate in stage III Kienböck's disease with micro-computed tomography imaging.

Seventeen fresh lunates with stage III Kienböck's disease were scanned with micro-computed tomography. Four regions of interest were selected to measure trabecular parameters, which were compared with those from normal lunates. Within the three regions in the distal surface, there was more compact trabecular bone in the middle region when compared with the palmar and dorsal regions. In the central part, the trabeculae of the Kienböck's lunates were much thicker than those in normal lunates. The diameters of the palmar nutrient foramina of the Kienböck's lunates were significantly smaller than those in normal lunates. In affected lunates, the bony disruptions were mostly located in the palmar or dorsal areas, which were shown from trabecular bone structure analysis to be structurally weaker. This leads to separation of the distal part of the fractured bone, disruption of the blood supply, poor bone remodelling and proneness to secondary fracture and eventual collapse.