Source https://www.nature.com/articles/s41584-019-0255-1

Injuries to articular cartilage and menisci can lead to cartilage degeneration that ultimately results in arthritis. Different forms of arthritis affect ~50 million people in the USA alone, and it is therefore crucial to identify methods that will halt or slow the progression to arthritis, starting with the initiating events of cartilage and meniscus defects. The surgical approaches in current use have a limited capacity for tissue regeneration and yield only short-term relief of symptoms. Tissue engineering approaches are emerging as alternatives to current surgical methods for cartilage and meniscus repair. Several cell-based and tissue-engineered products are currently in clinical trials for cartilage lesions and meniscal tears, opening new avenues for cartilage and meniscus regeneration. This Review provides a summary of surgical techniques, including tissue-engineered products, that are currently in clinical use, as well as a discussion of state-of-the-art tissue engineering strategies and technologies that are being developed for use in articular cartilage and meniscus repair and regeneration. The obstacles to clinical translation of these strategies are also included to inform the development of innovative tissue engineering approaches.

Key points

• Current cartilage repair techniques include surgery and cell-based therapies for articular cartilage, and surgery for meniscus repair; however, such treatments have limited capacity to induce regeneration.
• Tissue engineering strategies to create cartilage using a variety of cell sources and exogenous stimuli have made advances towards replicating the native architecture and functional properties of cartilage.
• Most cell-based tissue engineering products currently in clinical trials are indicated for knee articular cartilage, with very few indicated for hip cartilage or the meniscus.
• Allogeneic and non-articulating cartilage might serve as additional cell sources for engineered articular cartilage and meniscus products.
• The pro-inflammatory environment of arthritic joints and issues surrounding neotissue integration need to be addressed to maximize the clinical translation of new tissue-engineered products.