Bone remodeling, around an anatomical hip stem: a one year prospective study using DEXA

The loss of bone mass, as a consequence of bone remodelling, in the proximal third of the femur, is a factor that contributes to the failure of hip prostheses in the medium to long term. This periprosthetic remodelling occurs mainly during the first 12 months after the operation. The aim is to evaluate the behaviour at one year of a new anatomical stem, the ANATO® stem (2015-Stryker®), which is a redesign of its predecessor (ABG-ii®-Stryker stem) by means of bone densitometry.

Prospective, controlled study in which the changes in bone mineral density (BMD) observed around the seven areas of Gruen in a group of 61 patients affected by primary coxarthrosis, in whom an ANATO® stem was implanted, are analysed densitometrically. The healthy hip was taken as the control group. The existence of differences in the remodelling pattern according to sex, age and body mass index (BMI) was compared. The follow-up was during the first year after the intervention.

After one year of follow-up, decreases of bone mineral density in zone seven of -5.9% were observed, being this decrease statistically significant. No differences were found in the remodelling pattern according to age, sex and body mass index.

The ANATO® stem allows an efficient transmission of loads from the stem to the proximal femur. Only in zone seven significant bone atrophy is observed. Differences in age, BMI and sex do not seem to influence the bone remodelling around this new stem.