Figure 1.

Femoral heads coronal section 42 days after surgical AVN at the teres ligament origin after H&E staining. The right is without Alendronate treatment, control, showing distortion of the spherical head shape. On the top, the weight bearing zone, the articular cartilage looses its height and is associated with arthritic changes. The epiphysis height is changed along the head and is smaller on the weight bearing zone. The left is the femoral head with Alendronate treatment. The spherical head shape is preserved and looks like normal. The cartilage height is equal all along the head and is smooth. The epiphysial height is preserved and similar along the head in the weight bearing zone (above the teres ligament), and in the non-weight bearing zone area (below the teres ligament).