The Hip: Preservation, Replacement and Revision

Histologic Changes in Rickets

- Medullary bone:
    - decreased in quantity, & trabecula are thin & irregular;
    - feature that most sig helps to establish the dx is presence of layer of unmineralized bone (osteoid seam) surrounding mineralized segment;
    - trabeculae & cortex have less bone, & is surrounded by a layer of unmineralized bone (osteoid seam)
    - osteoid seams;
           - refers to the layer of unmineralized bone which surrounds the mineralized trabeculae;
           - osteoid seams may also be present in

- Epiphyseal Physis:
    - epiphyseal plate is enlarged in height and width;
    - hypertrophic cell zone:
            - there is gross distortion of the hypertrophic cell zone (enlarged and distorted) & poorly defined zone of provisional calcification;
            - normally orderly columns are lost and instead, there is a marked increased in axial height of zone, & there is disorderly & profligate profusion of cell
                      with only a small amount of intervening matrix;
            - there is  failure of mineralization and vascular invasion;
            - w/ exception of hypophophatasia and metaphyseal chondrodysplasia no other syndrome produces these changes;
    - resting a proliferative zones are normal;
    - zone of provisional calcification seen in pts w/ rickets is poorly defined with only a few of the defective bars between the almost non existant columns
            of chondrocytes showing deposition of mineral;
    - tongues of viable cartilage w/o evidence of active enchondral replacement

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Tuesday, September 6, 2011 3:58 pm