Burch-Schneider antiprotrusio cage for acetabular revision: a 5- to 13-year follow-up study

Ninety-six acetabular revisions using a Burch-Schneider antiprotrusio cage (BSAC) in 91 patients (53 women and 38 men), were evaluated retrospectively with a mean follow-up of 8.1 years (range 5–13 years). The mean age at surgery was 67.3 years (range 35–85 years). There were 3 re-revisions: 1 because of aseptical loosening and 2 because of deep infection. The Kaplan-Meier survivorship rate, with aseptic component loosening as the criterion of failure, was 92.4% (95% confidence interval, 85.1%-99.8%) at 13 years. Clinical evaluation of the surviving patients showed an increase in mean Merle d'Aubigné-Postel hip score of 8.8 points before surgery, to 15.1 points at the time of the last follow-up. Radiographic evaluation determined that 3 cages were considered definitely loose. The rotation centre of the hip was lowered an average of 4.3 mm and lateralised an average of 1.3 mm in this series. In the most severe cases (Paprosky 2C, 3A, and 3B), the hip centre was lowered 7.8 mm and lateralised 0.8 mm. The Burch-Schneider antiprotrusio cage long-term survival rate compares favourably with that for other devices. Acetabular reconstruction allows anatomic positioning of the cups and promotes good final results.