---

- Discussion:
     - following inital ischemic episode, most of the epiphysis is avascular;
     - while enchondral ossification temporaily halts, the articular cartilage, which is nourished by synovial fluid, continues to grow;
          - this results in widening of medial cartilage (joint) space & smaller ossification center in involved hip;
     - revascularization occurs from periphery;
          - resumption of enchondral ossification within the epiphysis begins peripherally and progresses centrally;
          - new bone is deposited on avascular bone, producing a net increase in bone density;
     - in subchondral area, bone resorption exceeds new bone formation;
           - point is reached during resorption when subchondral area becomes weak & is prone to collapse