Abstract
A poly (l-lactic) acid bioengineered anterior cruciate ligament (ACL) matrix has previously demonstrated the ability to support tissue regeneration in a rabbit ACL reconstruction model. The matrix was designed for optimal bone and ligament regeneration by developing a matrix with differential pore sizes in its bone and ligament compartments. Building upon past success, we designed a new bioengineered ACL matrix that is easier to install and can be used with endobutton fixation during ACL reconstruction. To achieve this, a new braiding procedure was developed to allow the matrix to be folded in half, making two-limbs, while maintaining its bone and ligament compartments. The osteointegration of the matrix with and without bone morphogenetic protein 2 (BMP-2) supplementation was evaluated in a rabbit ACL reconstruction model. Two doses of BMP-2 were evaluated, 1 and 10 μg, and delivered by saline injection into the bone tunnel at the end of surgery. A fibrous matrix-to-bone interface with occasional Sharpey’s fibers was the primary mode of osteointegration observed. The matrix was also found to support a fibrocartilage matrix-to-bone interface. In some cases, the presence of chondrocyte-like cells was observed at the aperture of the bone tunnel and the center of the matrix within the bone tunnel. Treatment with BMP-2 was associated with a trend towards smaller bone tunnel cross-sectional areas, and 1 μg of BMP-2 was found to significantly enhance osteoid seam width in comparison with no BMP-2 or 10 μg of BMP-2 treatment. Regenerated tissue was well organized within the bioengineered ACL matrix and aligned with the poly (l-lactic) acid fibers. Disorganized tissue was found between the two-limbs of the bioengineered ACL matrix and hypothesized to be due to a lack of structural scaffolding. This study suggests that the bioengineered ACL matrix can undergo similar modes of osteointegration as current autografts and allografts, and that BMP-2 treatment may enhance osteoblastic activity within the bone tunnels.
Highlights
400,000 anterior cruciate ligament (ACL) reconstructions are performed worldwide to repair ruptured ACLs
The bioengineered ACL matrix was designed to allow for the ease of insertion and to achieve higher peak loads than the native rabbit ACL, which has been reported to be 314 ± 68 N [6]
We investigated the osteointegration of a bioengineered ACL matrix with and without supplementation of bone morphogenetic protein 2 (BMP-2) delivered through a saline injection
Summary
400,000 anterior cruciate ligament (ACL) reconstructions are performed worldwide to repair ruptured ACLs. The gold standard grafts for ACL reconstruction are hamstring tendon and bone-patellar tendon-bone autografts and allografts [3]; autografts have the drawback of donor site morbidity and allografts have the potential for disease transmission and graft rejection [4] To overcome these drawbacks, research has focused on developing bioengineered matrices for ACL regeneration [5]. In a rabbit ACL reconstruction model, the bioengineered ACL matrix demonstrated dense collagen tissue ingrowth and vascularization at 12-weeks. This seminal study focused on the intra-articular regeneration of the scaffold but did not investigate the osteointegration of the bioengineered ACL matrix
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
