Introduction

The mid- or long-term results of acetabular revision total hip arthroplasty (THA) in Korea are rare. The purpose of this study is to report the mid-term radiographic results (> 5 years) of acetabular revision THA with porous-coated cementless Trilogy^® cup (Zimmer, Warsaw, IN, USA).

Purpose: Radiographic signs of osseointegration have been well established for cementless femoral components, but not for cementless acetabular components. At our institution using principles similar to those applied to cementless femoral components, we have observed apparent radiographic signs of osseointegration of porous-coated cups. We then hypothesized that these signs could be used to predict bone ingrowth of porous-coated acetabular components. Methods: In a series of 119 total hip arthroplasties with porous-coated cementless cups, we reviewed post-primary and prerevision serial radiographs and proposed five radiographic signs for detecting osseointegration of a porous-coated acetabular component: absence of radiolucent lines, presence of a superolateral buttress, medial stress shielding, radial trabeculae, and an infero-medial buttress. We compared the predictability of each sign to intraoperative findings of cup stability and measured the sensitivity, specificity, and intra-observer agreement of each sign. Results: . In our population, ninety-eight cups had three to five radiographic signs of osseointegration; of these, ninety-five cups (97%) were found to be bone-ingrown at the revision operation. Conversely, twelve cups had only one or no sign; of these, ten (83%) were clinically unstable at the revision operation. Conclusions: We concluded these five, readily detectable signs of acetabular osseointegration are very useful in predicting acetabular component stability found at surgery

Background: The Duraloc cup is a frequently used metal backed hemispheric porous-coated cementless acetabular cup. Published radiological data on loosening rates remain contradictory. Despite to this contradictory radiological data is the good clinical performance of this cup reported by many authors. The aim of our study was to evaluate radiological outcome (cup migration, acetabular abduction angle, cup anteversion) and possible correlation to clinical data after 12 years. Methods: Migration analysis of 40 cementless Duraloc 100 cups (38 patients, average age 57 years, range 52 to 68years, 25 male, 13 female) could be retrospectively performed after a 12 year follow up using Einzelbild-Roentgen-Analyse (EBRA) software. An average of 5 standardised anteriorposterior radiographs (range 4 – 8) could be evaluated. Clinical outcome was assessed using HHS score. Cup migration, acetabular abduction angle, cup anteversion, heterotocpic ossification and wear were determined. Statistical evaluation was performed using Mann- Whitney - U test and correlation analysis. Results: At 12 years follow up the average horizontal migration was 1.51 mm (range 0 to 8.5 mm) and the average vertical migration was 1.44 mm (range 0 to 4.5 mm). The average cup abduction angle was 48° (range 30° to 58°, average cup anteversion was 16° (range 12 to 25°) Average wear of the polyethylene liner at latest follow up was 1.5 mm (range 1.1 to 2.1). Harris hip score improved from average 41 (range 30 – 55) to 90 (range 77 to 95) at latest follow up. We could not find any significance difference between cup migration and gender (p > 0.05). There was no positive correlation between clinical scores and migration data found (r. 2. = 0.01). The cup diameter however showed positive correlation with cup migration (r. 2. = 0.8). Conclusion: Our study shows good radiological and clinical results of the Duraloc cup after 12 years. Radiological migration data did not show any correlation with clinical results. A greater cup diameter however is a risk factor for higher migration