Healing of tibial bone tunnels after bone grafting for staged revision anterior cruciate ligament surgery: A prospective computed tomography analysis

Aim: To quantify healing of tibial bone tunnels after bone grafting in two-stage ACL reconstruction revision. Methods: Ten consecutive patients underwent autogenous bone grafting prior to ACL reconstruction revision (four females and six males, average age 28 years). The indications for two-stage surgery were as follows: (1) the enlargement of the tibial tunnel aperture was >20 mm in diameter or, (2) the existing tunnel was overlapped with the optimal tunnel and positioned more than a half tunnel diameter posterior to the optimal position. An autogenous iliac bone block was driven into a new tunnel. CT examinations were performed at three, 12 and 24 weeks after bone grafting. Evaluations were performed on 15 axial planes at one-millimeter intervals from the articular surface perpendicular to the long axis of the tibia using the following three parameters: occupying ratio (OR), union ratio (UR), and bone mineral density (BMD) of grafted bone. Results: The average ORs were 81, 85 and 94%, and the average URs were 49, 75 and 89% at three, 12 and 24 weeks, respectively. Each parameter significantly increased over time. The average BMD was 510 and 571 mg/cm(3) at 12 and 24 weeks, respectively, with a significantly higher value at 24 weeks. Conclusion: The average ORs, URs and BMD at 24 weeks after bone grafting were higher than those at 12 weeks, which suggests that at 24 weeks after bone grating, the condition of the patients' beds becomes favorable for safe implantation and fixation of ACL graft revision. (C) 2016 Elsevier B.V. All rights reserved.