THE EFFECT OF PHYSEAL TRACTION APPLIED TO THE TRIRADIATE CARTILAGE ONACETABULAR GROWTH

Physeal distraction was applied with an external fixator to the trirad iate cartilage of dogs with the aim of increasing the capacity of the acetabulum, The force was continued for from 2 to 6 weeks and the cons equent changes were evaluated with regard to function and structure by radiography and microscopy. The distraction, without producing epiphy siolysis and destruction of the cartilage, resulted in expansion of th e pelvic bones. The depth and volume of the acetabulum were increased, but the acetabular angle was decreased. Distraction also caused proli feration of the lacunar cells and the number of mammillary processes i n the cartilage columns increased. Distraction can therefore be applie d to the triradiate cartilage to enlarge the capacity of the acetabulu m without producing epiphysiolysis.