|| Checking for direct PDF access through Ovid
ACL injuries affect a large number of people, and such injuries lead to joint instability and increased risk for degenerative joint disease later in life. Reconstruction of the damaged joint using an in vitro engineered ACL replacement construct is becoming more of a reality and avoids the risk of allografts or the donor site morbidity associated with autografts. Whereas progress has been made in generating engineered tissues for ACL replacement in model systems, several challenges still remain. These include the choice of a suitable scaffold (components of normal tissue or biodegradable materials), the density and differentiation state of appropriate cells, the biomechanical environment required for optimal in vitro generation, parameters required for successful engraftment, and the biologic diversity of the host. Whereas the solutions to these challenges are being addressed by various groups and progress is being made, there are still gaps in our understanding of how to generate, implant, and ensure the success of these engineered tissues. This review discusses the current status of engineering ACL replacements and the challenges remaining.