The study suggests the potential of the novel 3D PCL scaffold augmented with MSCs as an alternative meniscal substitution, although this approach requires further improvement before being used in clinical practice.

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BackgroundPosterior Cruciate Ligament (PCL) ruptures are common sports injuries. One of the key controversies in PCL reconstruction is whether double-bundle reconstruction provides biomechanical and clinical outcomes superior to single-bundle reconstruction.MethodsWe performed a comprehensive search in multiple databases to evaluate the advantages of single-bundle or double bundle reconstructions in anteroposterior stability, graft tension, rotational stability, and functional outcome.ResultsBiomechanical comparisons evaluating anteroposterior stability described either no difference or increased stability in double-bundle reconstructions. Comparing these results is complicated by different graft choices, tensioning techniques, and tunnel positions. Biomechanical studies of graft tension demonstrated conflicting results regarding the optimal reconstruction technique. Seven retrospective clinical studies of single- and double-bundle reconstructions with methodological limitations reported no difference in clinical outcome.ConclusionsThe superiority of single-bundle or double-bundle posterior cruciate ligament reconstruction remains uncertain.

Abstract:A three-dimensional (3D) composite scaffold was prepared for enhanced cartilage tissue engineering, which was composed of a poly(ε-caprolactone) (PCL) backbone network and a poly(lactide-co-glycolide)-block-poly(ethylene glycol)-block-poly(lactide-co-glycolide) (PLGA-PEG-PLGA) thermogel surface. The composite scaffold not only possessed adequate mechanical strength similar to native osteochondral tissue as a benefit of the PCL backbone, but also maintained cell-friendly microenvironment of the hydrogel. The PCL network with homogeneously-controlled pore size and total pore interconnectivity was fabricated by fused deposition modeling (FDM), and was impregnated into the PLGA-PEG-PLGA solution at low temperature (e.g., 4˝C). The PCL/Gel composite scaffold was obtained after gelation induced by incubation at body temperature (i.e., 37˝C). The composite scaffold showed a greater number of cell retention and proliferation in comparison to the PCL platform. In addition, the composite scaffold promoted the encapsulated mesenchymal stromal cells (MSCs) to differentiate chondrogenically with a greater amount of cartilage-specific matrix production compared to the PCL scaffold or thermogel. Therefore, the 3D PCL/Gel composite scaffold may exhibit great potential for in vivo cartilage regeneration.

As a cell source with large quantity and easy access, peripheral blood mesenchymal stem cells (PBMSCs) were isolated and seeded in porcine demineralized cancellous bone (DCB) scaffolds, cultured in chondrogenic medium and evaluated for in vitro chondrogenesis. Bone marrow MSCs (BMMSCs) and articular cartilage chondrocytes (ACCs) underwent the same process as controls. The morphology, viability and proliferation of PBMSCs in DCB scaffolds were similar to those of BMMSCs and ACCs. PBMSCs and BMMSCs showed similar chondrogenesis potential with consistent production of COL 2 and SOX 9 protein and increased COL 2 and AGC mRNA expressions at week 3 but the COL 2 protein production was still less than that of ACCs. Minimal increase of hypertrophic markers was found in all groups. Relatively higher ALP and lower COL 10 mRNA expressions were found in both MSCs groups at week 3 than that in ACCs, whereas no significant difference of COL 1 and SOX 9 mRNA and MMP 13 protein was found among all groups. To conclude, PBMSCs shared similar proliferation and chondrogenic potential with BMMSCs in DCB scaffolds and could be an alternative to BMMSCs for cartilage tissue engineering. Further optimization of chondrogenesis system is needed regardless of the promising results.