Damage to joint cartilage is painful and limits mobility. Researchers at the University of Basel and the University Hospital of Basel are therefore developing cartilage implants from cells from the nasal septum. A recent study shows that a longer maturation time for the cultured cartilage brings a significant improvement even in cases of complicated cartilage injuries. This suggests that the method could also be suitable for the treatment of joint arthrosis.

An unfortunate fall while skiing or playing football can mean the end of sporting activity. Cartilage damage to joints does not heal on its own and increases the risk of osteoarthritis. Researchers at the University of Basel and the University Hospital of Basel have now shown that even complicated joint cartilage injuries can be repaired with replacement cartilage grown from the patient’s own cells from the nasal septum.

A team at the Department of Biomedicine led by Prof. Dr. Ivan Martin, PD Dr. Marcus Mumme and Prof. Dr. Andrea Barbero has been researching this method for several years. They take a tiny piece from the patient’s nasal septum and multiply the cartilage cells in the laboratory on a scaffold made of soft fibers. They then cut this replacement cartilage into the required shape and implant it into the knee joint.

Previous studies have already shown promising results. “The nasal cartilage cells have special properties that are ideal for cartilage regeneration,” explains Ivan Martin. For example, it turned out that these cells can counteract inflammation in the joint.

Well-matured cartilage shows better results

In a clinical study with 98 participants in clinics in four countries, the researchers compared two approaches: One group received cartilage replacement that had been pre-matured in the laboratory for just two days before implantation – a period that is also used for other cartilage replacement products. For the other group, the researchers allowed the cartilage replacement to mature for two weeks. During this time, the tissue gains cartilage-like properties.

For 24 months after the procedure, the participants documented their well-being and the functionality of the treated knee using a questionnaire. The results, published in the journal “Science Translational Medicine”, show that the transplantation of the cultured cartilage led to a significant improvement in both groups. In the group with the longer-matured cartilage, the condition improved even further in the second year after the procedure and exceeded that of the group with the shorter-matured variant.

Additional examination using magnetic resonance imaging showed that the longer pre-matured cartilage led to a better composition of the tissue at the site of the implant and even of the neighboring cartilage. “The longer pre-maturation is worth it,” emphasizes Anke Wixmerten, co-first author of the study. The additional maturation of the implant only increases the effort and costs slightly and achieves significantly better results.

Particularly suitable for larger and more complex defects

“It is remarkable that patients with larger injuries benefit from the longer-matured cartilage,” says Andrea Barbero. The same applies to cases in which cartilage injuries have already been treated with other techniques, but the result was unsatisfactory.

“We did not make a direct comparison with standard treatments in our study,” admits Ivan Martin. “But if you look at the results from standard questionnaires, patients achieve higher values ​​in joint functionality and quality of life in the long term after treatment with our method.”

Based on these and previous results, the researchers now want to test this method for the treatment of osteoarthritis – an inflammatory disease that breaks down joint cartilage and causes pain.

Two large-scale clinical studies funded by the Swiss National Science Foundation and the EU’s Horizon Europe research framework program are in the starting blocks to investigate the benefits of the technology in patellar osteoarthritis. With these projects, the team is complementing the research focus on cellular therapies, which the University of Basel and the University Hospital Basel promote as one of their priorities.

Marcus Mumme, Anke Wixmerten et al.
Clinical relevance of engineered cartilage maturation in a randomized multicenter trial for articular cartilage repair
Science Translational Medicine (2025), doi: 10.1126/scitranslmed.ads0848