Osteochondral Defect Repair after Implantation of Biodegradable Scaffolds: Indirect Magnetic Resonance Arthrography and Histopathologic Correlation

Background: Biodegradable scaffolds have become an important option in the treatment of osteochondral defects. Therefore, accurate and reproducible monitoring of scaffold repair tissue is crucial.Purpose: To assess the feasibility of indirect magnetic resonance (MR) arthrography in determining the quality of osteochondral repair after scaffold implantation using an MR imaging (MRI) scoring and grading system with histology as reference.Material and Methods: Osteochondral defects created at ovine condylar facets were treated with either a commercial poly (DL-lactide-co-glycolide) (PLG) scaffold or a modified softer one (n=6/group; 87% and 55% of the elastic modulus of ovine subchondral bone, respectively). Empty defects at the contralateral condyle served as control group. A 1.5T MRI scan was performed after 6 months with proton density (PD)-weighted (w) fat-saturated (fs) fast spin-echo (FSE), T1-w two-dimensional (2D), and 3D fs gradient echo (GE) sequences 30min after intravenous Gd-DTPA administration ...