Radiological Assessment of Porous-coated Acetabular Component with Screw Fixation in Primary Total Hip Arthroplasty

Yoo, Chong Il; Suh, Kuen Tak; Lim, Kyoung Sam

Abstract

This is a follow up study on 124 cases of primary total hip arthroplasty with Harris-Galante porous-coated acetabular component with the line-to-line technique, performed at the Department of Orthopaedic Surgery, Pusan National University Hospital from January 1986 to February 1992. The follow-up ranged from 24 months to 92 months, the average being 53 months. The results were as follows; 1. At the last follow-up, a radiolucent line was found in 20 cases(16.1%), but the width was less than one millimeter. Among the 20 cases, the continuous radiolucent line was found in two cases(1.6%), the progressive radiolucent line in five cases(4.0%). 2. Areas of non-contact(initial gap) between the porous mesh of the acetabular component and the bone were seen on the immediate postoperative radiographs of 35 cases(28.2%) among 124 cases. A radiolucent line developed around 13 cases(34.2%) of the 35 cases that were associated with an initial gap, but a radiolucent line developed around only seven cases(7.8%) of the 89 cases(71.8%) not associated with such a gap. 3. At the last follow-up, a vertical migration was found in five cases(4.0%), an angulation change of the acetabular cup in two cases(1.6%), but a horizontal migration of the acetabular cup was not found. 4. There was no evidence of the disruption of the titanium porous mesh of the acetabular component, and loosening, bending or breakage of the screw for fixation of the acetabular cup. And there was no revision for acetabular loosening. In conclusion, because overall loosening rate was less than 5%, the results were very satisfactory. Considering an initial gap is a important factor of acetabular loosening, we think that it is important to make less initial gap during operation.