Component motion in bipolar hip arthroplasty: an evaluation of reamed and non-reamed acetabula.

Abstract

Sixty-four patients with 67 bipolar arthroplasties of the hip were reviewed for a mean follow up of 3.1 years. The study group consisted of 46 hemiarthroplasties secondary to primary osteoarthritis of the hip and 21 hemiarthroplasties secondary to displaced subcapital hip fractures. Reaming of the acetabulum was performed in 47 of the hips studied. The Harris hip scores were not significantly affected by acetabular reaming. Total motion decreased when hips were loaded in the standing position. Reaming of the acetabulum resulted in a decrease in percent outer component motion and an increase in percent inner component motion. The non-reamed acetabula had the largest percent inner motion decrease when taken from the supine to the standing position. The reamed acetabula had significantly higher average percentage of inner component motion in both standing and supine positions. There was no patient with postoperative acetabular protrusion.