Morselized allograft in acetabular reconstruction. A postmortem retrieval analysis.

Abstract

Contained acetabular defects often are repaired at revision surgery using morselized bone allograft. The extent to which this graft becomes incorporated is unknown, and the value of radiographs for predicting allograft incorporation is unclear. To better understand the effectiveness of morselized allograft in revision hip arthroplasty, the authors studied postmortem specimens from 3 patients treated with this type of graft. Histologic analysis of acetabular components in situ for 18 months showed allograft fragments invested with loose myxofibrous tissue. Vascularized tissue had penetrated the allograft fragments to a depth of 4 mm. In peripheral areas, the vascularized ingrowth was accompanied by partial osteoclastic resorption of graft trabeculae and application of living bone to allograft fragments. After 53 months in situ, graft fragments had remodeled and showed progressive vascular ingrowth. By 83 months, the graft almost completely had incorporated. Morselized allograft bone is useful for restoring bone deficiency within contained acetabular defects. The graft does incorporate, but the extent of graft incorporation cannot be predicted accurately by postoperative radiographs.