Of 451 cases treated by the non-bleeding technique at Department of Orthopedic Surgery, Okayama University Medical School for the period from June 1954 to December 1955, the author pursued the 47 cases on which the follow-up study was possible for the periods of 3 years and one month to 4 years and seven months after the treatment, and obtained the following results.
1. For the treatment of infants with congenital dislocation of hip joints we took a special care so as to keep the tissue damage as little as possible by the atraumatic technique. As a consequence with one exception that developed cerebral paralysis in all other 46 cases we were able to obtain excellent clinical results. 2. However, by the X-ray examination the majority of them revealed the roof of acetabulum to be still steep and also the head of femur to have moved slightly exteriorly upward. Moreover, at this instance various measurement of α angle, h/1 and H/1 were significant, but CE angle and Schenton line was not. Furtnermore, although the atrophy and sclerosis of bone can not be represented numesically, it is believed that these will have a significant bearing on the treatment and prognosis of congenital dislocation of hip joints. 3. From the examinations of the tissues obtained from the edge of the acetabular roof of foetus and of the biopsy specimen from infants both with dislocation of the hip joint, it is assumed that the congenital defect of mesenchym coupled with the kinetic relationship between the roof of acetabulum and the head of femur presents pathological findings. 4. For those showing a poor growth of the acetabular roof in congenital dislocation of hip joint during the treatment by non-bleeding technique and still revealing a steep acetabular roof we replaced the cartilagenous tissues of that part by trephin, expecting to promote the growth in that part. The results were at variance, and in the final analysis, it seems that a more important problem in such cases is the method how the head of femur may be kept centripetally.