Trabecular Metal buttress augment and the Trabecular Metal cup-cage construct in revision hip arthroplasty for severe acetabular bone loss and pelvic discontinuity

Abstract

Large acetabular defects can be reconstructed using a tantalum Trabecular Metal acetabular component with Trabecular Metal buttress augments. We asked if these reconstructions survived at short-term follow-up. Of 35 patients undergoing acetabular reconstruction with a Trabecular Metal acetabular revision system from 2006, 19 acetabular revisions associated with major bone loss in which we reconstructed the acetabulum with buttress tantalum augments or cup-cage construct combined with a Trabecular Metal shell, were available for evaluation. Mean follow-up was 26 months (range 18-43 months). Mean patient age was 63 years, and 12 patients were women. All defects were classified according to Paprosky and Saleh classifications; there were 13 type IIIA and 6 type IIIB acetabular defects. Five chronic pelvic discontinuities were preoperatively or intraoperatively assessed (Saleh type 5) and a cup-cage construction was employed. No mechanical failure has occurred in any hip, and all patients have radiographically stable cups. Radiographic assessment showed an improvement in the position of the rotation centre of the hip, from a vertical position a mean of 3.5 cm (range 1.6-5.5 cm), to 1.4 cm (range 0.5-2.7 cm) postoperatively. The centre of the femoral head was relocated from a mean of 1.4 cm (range, -3 to 2.6 cm) lateral from the vertical at the teardrop to 3 cm (range 0.2-4 cm). Our early results suggest that buttress tantalum augments, with cup-cage construct for severe bone defects, may be an alternative to other treatment options, but a longer follow-up is necessary.