IMPACTED GRAFT INCORPORATION AFTER CEMENTED ACETABULAR REVISION - HISTOLOGICAL-EVALUATION IN 8 PATIENTS

We took core biopsies from the acetabulum in 8 patients (at reoperatio n) after a previous revision with impacted cancellous allograft chips in combination with cement. Except for one biopsy specimen, the graft showed different stages of incorporation. In the specimens taken at 4 months, revascularization of the graft was found. Osteoclasts had remo ved parts of the graft, while woven bone had formed on the remnants of the graft and in the stroma that was invading the graft. Subsequent s pecimens showed that this mixture of graft and new bone was in due tim e remodeled into a normal trabecular bony structure with viable bone m arrow that contained little or no remnants of the original graft. The graft-cement interface was present in 4 biopsies taken at 1, 22, 28, a nd 72 months. The specimen obtained 28 months after revision showed vi tal bone locally in direct contact with the cement layer; however, a s oft tissue interface predominated.