To compare implant survival rates after total hip arthroplasty with Exeter matte or polished stems and to determine the relationship of synovitis/joint effusion to signs of implant loosening and stem type.
The first part of the study included retrospective revision rate analysis of 118 primary hip replacements performed during 1991-1995. Two different designs of Exeter stems were used: matte surface stems during 1991-1995 (matte surface group--47 cases), and polished stems during 1992-1995 (polished stem group--71 cases). During the second part of the study, 24 patients (11 in polished stem group and 13 in matte stem group) were prospectively examined with radiography and sonography. Sonography was performed in order to evaluate capsular distension, i.e. the distance between prosthetic femoral neck and anterior capsule. Capsular distension depends on synovitis and/or synovia in prosthetic hip. The relationship between capsular distension, stem type, and radiographic signs of loosening was assessed.
For the first part of our study, total implant survival was 78% with matte stems and 61% with polished stems 13 years postoperatively (P=0.27). Stem survival was 82% for matte stems, and 88% for polished stems (P=0.54). In the second part of study, a significant relationship between increased capsular distension and cup loosening was determined (P=0.04). We did not find significant difference in capsular distension when compared matte and polished stems.
Implant survival rates did not differ between the groups. The relationship between capsular distension and cup loosening was statistically significant.