Early loosening of femoral components after cemented revision. A roentgen stereophotogrammetric study.

Roentgen stereophotogrammetric analysis was used to measure the migration of 24 cemented femoral components implanted during revision for mechanical loosening. All hips were examined one week, four months and one year after surgery; 14 hips were also examined after two years. Twenty-one components subsided 0.2 to 5.5 mm during the observation period; in 17 of these, subsidence occurred within four months of surgery. In 16 hips the prosthetic head was displaced 0.7 to 11.2 mm posteriorly. The fixation of the femoral components was less secure than after primary arthroplasty, especially in cases of femoral canal enlargement, when a standard-sized rather than a thick-stemmed prosthesis had been used, and in cases of inadequate cement filling.