Cartilage Repair in Knee Osteoarthritis

Knee osteoarthritis is characterised by progressive loss of articular cartilage, subchondral bone changes and chronic pain. Once damaged, cartilage has limited intrinsic capacity for repair, owing to its avascular, aneural nature. Contemporary strategies seek to restore cartilage structure and function by stimulating local repair or by implanting engineered tissues. Techniques range from marrow stimulation (microfracture) to cell-based approaches such as autologous chondrocyte implantation, and from simple scaffolds to complex multilayer constructs that address both cartilage and underlying bone. Recent advances include cell-free biomimetic scaffolds, injectable hydrogels and stem cell–laden matrices, each aiming to promote hyaline-like tissue formation, integrate with host tissue and withstand mechanical loads. Attention has also turned to the osteochondral unit as a whole, recognising that durable cartilage repair requires support from a healthy subchondral bone bed. Innovations in biomaterials, combined with imaging-guided delivery and bioreactor preconditioning, are bringing closer the goal of true tissue regeneration rather than mere symptom relief. Clinically, these developments promise joint preservation, functional improvement and delay of arthroplasty, addressing a global burden affecting millions of active and ageing individuals.

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Cartilage Repair in Knee Osteoarthritis publication trend

The graph below shows the total number of articles in cartilage repair in knee osteoarthritis across all publications each year (not limited to Nature Index journals).

Technical terms

Osteoarthritis: A degenerative joint disease involving cartilage breakdown, bone remodelling and synovial inflammation.

Chondrocyte: A specialised cell resident in cartilage responsible for producing extracellular matrix components such as collagen and proteoglycans.

Scaffold: A three-dimensional biomaterial framework that supports cell attachment, proliferation and tissue formation.

Microfracture: A surgical marrow-stimulation technique that creates small holes in subchondral bone to induce a reparative cartilage clot.

Osteochondral defect: A lesion involving both the cartilage surface and the underlying subchondral bone.

Subchondral bone: The layer of bone just below the cartilage that provides mechanical support and supplies nutrients to the cartilage.

References

1. Female patients report comparable results to males after the implantation of an aragonite-based scaffold for the treatment of knee chondral and osteochondral defects: a gender-based analysis of a RCT at 4 years’ follow-up. Journal of Orthopaedics and Traumatology (2025).
2. Long-Term Culture Performance of a Polyelectrolyte Complex Microcapsule Platform for Hyaline Cartilage Repair. Bioengineering (2023).
3. In vitro and in vivo evaluation of the osseointegration capacity of a polycarbonate‐urethane zirconium‐oxide composite material for application in a focal knee resurfacing implant. Journal of Biomedical Materials Research Part A (2024).