Abstract
We examined 12 cases (13 joints) of total surface replacement of the hip an average of 6 years and 4 months after operation (4 years for the shortest, 7 years and 7 months for the longest), and obtained the following results:
1) Of these 13 joints, 7 showed loosening, a high incidence rate of 53.8%.
2) Statistical examination of cases with loosening and non-loosening revealed that occurrence of loosening depended upon whether the preoperative condition of the hip joint on the nonoperated side was normal or abnormal, namely, loosening develops when there is an excessive load upon the hip joint of the operated side.
3) In revision cases, from histological findings of tissue necrosis it would seem that there was some mechanical stress, which was followed by reactive proliferation of histiocytes, leading to fragility.
4) From the morphological viewpoint, the above suggests that it is preferable that the load on an artificial joint be dispersed over a wide area.
