Type III acetabular defect revision with bilobed components: five-year results.

UNLABELLED: Combined segmental and cavitary deficiencies of the acetabulum (American Academy of Orthopaedic Surgeons Type III) are a difficult problem that revision arthroplasty surgeons must tackle with increasing frequency. Porous-coated bilobed acetabular components are a reconstruction option that allows for increased host bone-prosthesis contact with restoration of the anatomic hip center without the use of a structural bone graft. Eleven consecutive Type III acetabular defects in 11 patients were revised with a porous-coated bilobed cup without a structural bone graft between January 1999 and January 2001 and prospectively followed. Average Harris hip scores improved from 36 preoperatively to 85 postoperatively. Radiographic analysis showed improvement in the average vertical displacement of the hip center. Average leg length discrepancies decreased from 34 mm preoperatively to 7 mm postoperatively. There have been no revisions performed or planned. Porous-coated bilobed acetabular components can provide good clinical and radiographic results at intermediate followup for treatment of Type III acetabular deficiencies. Bilobed components offer a viable option for reconstruction of Type III defects without the use of a structural bone graft or cement while maximizing the host bone-implant contact and restoring the native hip center. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.