Hydrogels are indeed one of the most promising avenues in regenerative cartilage medicine. The principle behind them is to create, directly at the site of the injury, a three-dimensional matrix capable of harbouring cells and promoting the formation of new cartilage tissue. Several German research teams have been working on this technology for years. The German Research Foundation has, in particular, funded research into hydrogels that form directly at the site of injury and are designed to regenerate cartilage.
However, there is a significant difference between an experimental hydrogel and a treatment that simply enables ‘cartilage to regrow’ following an injection.
One of the most advanced German technologies is NOVOCART Inject, developed around the implantation of autologous chondrocytes. The principle involves harvesting cartilage cells from the patient, multiplying them in the laboratory and then reintroducing them into the lesion within a hydrogel. The hydrogel solidifies directly in the area to be repaired and holds the cells in place.
The clinical results are promising. In a phase III multicentre trial involving 100 patients with significant localised lesions of the knee cartilage, 93 per cent of patients met the defined criterion for clinical improvement after two years. MRI scans simultaneously indicated progressive maturation and integration of the repaired tissue.
A follow-up study published subsequently at the five-year mark also provides data on the durability of the results. An analysis of the German Cartilage Register published in 2024, for its part, compared this technique with another form of chondrocyte implantation. Both approaches yielded favourable results at two years, although the authors emphasise that the clinical relevance of certain benefits observed with the hydrogel remains to be demonstrated.
It is therefore much more than a simple laboratory experiment.
However, presenting this technology today as a gel capable of regenerating a joint ‘without surgery’ is misleading. In the German clinical trials, cartilage cells are first harvested during arthroscopy, cultured for several weeks, and then the product containing these cells is placed into the lesion via arthroscopy or through a small surgical incision. Specific rehabilitation follows the procedure.
In other words, it is not yet the equivalent of an injection administered in a few minutes at the GP’s surgery.
A distinction must also be made between localised cartilage lesions and advanced osteoarthritis. The trials cited mainly concern well-defined cartilage defects in the knee. They do not demonstrate that a knee whose cartilage has been largely destroyed by severe osteoarthritis can currently be fully regenerated by means of a simple injection.
The next step is particularly exciting: developing hydrogels capable of acting with much less external intervention, or even without the addition of cultured cells. International research is already exploring so-called ‘cell-free’ gels, designed to attract the body’s own stem cells and promote their transformation into cartilage cells. Impressive results have been achieved in experiments, but their transition to routine use in humans remains to be established.
The viral post therefore contains a grain of truth, but it skips several steps. Yes, hydrogels capable of aiding cartilage repair do exist. Yes, technologies developed and studied in Germany have already produced encouraging clinical results in humans. No, we do not yet have a miracle gel that can be injected into any arthritic joint to spontaneously rebuild its cartilage without surgery.
But behind the exaggeration on social media lies a genuine advancement in medicine: rather than systematically replacing a damaged joint with an artificial one, the aim is gradually shifting towards giving the body the means to repair its own tissues. And that revolution is very real.
