[Bony changes at the femur side after hip joint replacement: radiologic analysis of 80 hip joints]

The authors, according to Amstutz, studied the roentgenographs of 80 postoperation cases of cemented hip joint replacement performed more than two years-ago. There were bone changes in 64 cases (80%), of them, sclerosis of bone in 32 cases (40%), atrophy of bone in 25 cases (31%), absorption of bone in 24 cases (30%), thickness of bone cortex in 18 cases (22%), enlargement of medullary cavity in 12 cases (15%), periosteum reaction in 8 cases (10%), and thinness of bone cortex in 1 case (1.3%). Most of them usually occurred in the sixth month to the second year post-operation and located mainly at the 1, 4, 5 and 7 regions. The authors think that the most important cause is the unbalance of biologic stress, and other factors are elasticity and hardness of prosthesis, frictional force, cemented of the stem, etc.