Introduction: Our aim is to study the morphological changes (and related factors) that occur in the proximal femur in patients with THR with a minimum 10 year follow-up.

Materials and methods: We have included 50 THRs carried out between October 1992 and June 1995 with porous stems with metaphyseal support proximally coated with hydroxyapatite. Changes in the morphology and density of the proximal femur and its relationship with several factors, especially polyethylene wear, were carried out by means of a series of x-rays taken during the whole period of evolution and a spiral CT taken during the last review.

Results: There was no subsidence, stem migrations or femoral revision surgery. After one year, all patients show an sclerotic region in the area of metaphyseal support that remains stable throughout the study period. During this period, only two other types of changes were seen in the proximal area.

lytic areas surrounded by a halo of sclerosis in the greater trochanter (in 18 cases they were very small and in 14 cases of a greater size). These areas were statistically significantly related to a greater rate of wear;

Conclusions: The metaphyseal area of the stem continued to comply with its support function during the period studied. In more than half of the cases there was some sort of bone loss in the proximal area. There is a relationship between polyethylene wear and the appearance of areas of lysis in the trochanter.