**Acknowledgements**

This research was supported by funding from the AO Foundation in Acute Cartilage Injury Collaborative Research Program (ACI CRP) under the project "Bioactive and biomimetic scaffolds for cartilage regeneration" (BIOCART) and OSTEOCHON3D, and grants from the NIH (AR50245, AR48852, AG15768, AR48182, AG46927).
