Bone Metabolism after Total Hip Revision Surgery with Impacted Grafting: Evaluation using H215O and [18F]fluoride PET; A Pilot Study

PURPOSE: To evaluate bone blood flow and bone formation in patients after total hip revision surgery with impacted bone grafting using H(2) (15)O and [(18)F]fluoride positron emission tomography (PET). PROCEDURES: To asses bone blood flow and bone metabolism in bone allograft after impaction grafting, four patients treated with total hip revision surgery were enrolled prospectively in this study. Six patients scheduled for primary hip arthroplasties were included as a control group. The study protocol consisted of three H(2) (15)O and [(18)F]fluoride PET scans in each patient. RESULTS: Bone blood flow increased significantly compared to the preoperative state in patients treated for primary hip arthroplasty. In patients undergoing revision surgery, bone blood flow was twofold to threefold higher compared to the preoperative state, but did not reach significance. Bone metabolism in patients undergoing revision was threefold higher 2 weeks postoperatively compared to the primary hip group. We found a significant correlation between Ki and bone blood flow. CONCLUSIONS: Allogeneic bone grafts induce a higher rate of local periprosthetic bone formation compared to periprosthetic bone formation after a primary total hip placement. In vivo coupling between bone blood flow and bone metabolism suggests that bone metabolism in allogeneic bone grafts may partly rely on bone blood flow adaptations.