Abstract
Studies were carried out to elucidate the nature of the reduction and fixation difficulties and the resulting deformity brought about during the treatment of the congenital dislocation of hip joint.
Traumatic dislocation of the hip joint was made in 120young rabbits three weeks old and weighing 200 grams, and of thes closed reduction was successfully performed in twenty-five. The rabbits were sacrificed for the anatomical evaluation of the treated joints and the following results were obtained.
1.The changes seen in the soft tissues were hemorrhage and contracture.
2.The recovery of the joint capsule injury was rapid, but resulted in marked thickening and adhesion in part to the gluteal muscles making the descending of the head difficult.
3.In the experimental dislocation fibrous tear was seen and the elongated ligament Caput femoralis was disrupted near its insertion to the femoral head in all cases. The end of the ligament was pushed between the acetabulum and femoral head in abnormal position.
4.The depth of the acetabulum gradually decreases from abnormal growth of the consisting bones and increasing growth of connective tissue to apoint the acetabulum forms itself a triangular shape. This makes the acetadulum unfitted to the femoral head, resulting fixation difficulty.
5.There was little change in the articular cartilage of the femoral head, in the latter of which coxa vara deformity was present.Histologically eauly termination of epiphyseal guowth, fibuosis ofthe bone marrow in the captial epiphyses and neck, and the atrophy and disappearance of the trabeculae were seen. It is suspected that the deformity of the femoral head would be due to the circulation disturbance of the femoral neck and the early termination of the epiphyseal growth from the traumatic effect to epiphyses of the manipulation.
