Can One Injection Ease Knee Arthritis for Five Years? An Orthopedist Weighs In

Arthrosamid takes a different approach. The hydrogel integrates into the synovialis, durably altering its structure and, presumably, the joint's inflammatory environment as well. This can reduce pain and improve joint function.

What I want to be clear about, however, is this: Arthrosamid does not rebuild articular cartilage that has already been lost. It is not a "cure for osteoarthritis," but rather a long-term treatment of its symptoms and the joint environment.

Five Years After One Injection: What the Long-Term Data Show

According to a recent study, pain and mobility were still improved five years after a single injection. That sounds almost too good to be true — how much of it holds up?

I find this data extremely interesting. The fact that a single injection still produces a meaningful improvement in pain and function after five years is remarkable for a conservative osteoarthritis therapy.

That said, it is important to stay scientifically level-headed. Patient numbers in the long-term studies are still modest, and we do not yet have the same breadth of independent data as we do for treatments that have been in use for decades.

What additionally convinces me personally is how consistent the study findings are with our own clinical experience. We see a very long-lasting effect in many patients. That is not a controlled study, of course, but with around 200 treated patients, it represents a meaningful body of real-world experience.

The Gap Between Hyaluronic Acid and Knee Replacement

Who is this treatment suitable for?

Primarily for patients with symptomatic knee arthritis in whom standard conservative measures are no longer sufficiently effective, but for whom surgery is still to be avoided or delayed as long as possible.

I find the procedure particularly valuable for moderate to even advanced osteoarthritis. This is exactly where a therapeutic gap often exists: for a straightforward hyaluronic acid treatment, the osteoarthritis is in some cases already relatively far advanced, yet the patient is not ready for a knee replacement. In precisely this situation, Arthrosamid can be a very compelling option.

What is always decisive for me, however, is never the X-ray or MRI image alone. We treat the patient and their symptoms — not just the radiological grade of osteoarthritis.

Are there patients for whom you would advise against a hydrogel injection?

Yes. An acute joint infection or a significant infection in the area of the injection site is of course a contraindication. Even with a severely inflamed joint, the source of the inflammation must be identified and addressed first.

I am also cautious when a pronounced mechanical problem is present — for example, significant joint malalignment, instability, or advanced joint destruction with severe functional impairment. An injection cannot substitute for a procedure that is mechanically necessary.

That is why every treatment at our practice is preceded by a thorough clinical and imaging assessment.

Can hydrogel be combined with regenerative procedures such as PRP, or does that not make medical sense?

In my view, it makes perfect sense — though not with the mindset of "inject as much as possible all at once." I see these treatments more as different building blocks within an individualized treatment concept.

Arthrosamid can serve as a kind of long-term baseline therapy. If residual symptoms persist after a few months, PRP — possibly combined with hyaluronic acid — can be added as a supplement. We frequently use such graduated concepts in our practice.

PRP addresses the biological and regenerative dimension more directly, while the hydrogel acts over the long term through its integration into the synovialis. From a clinical standpoint, these different mechanisms of action can complement each other in a meaningful way. However, we still need considerably more scientific data on such combination approaches.

Side Effects: Why Injection Technique Matters

What risks should patients be aware of?

Overall, a favorable safety profile has been observed to date. The most common reactions are temporary pain, a feeling of pressure, or irritation and swelling of the joint after the injection. As with any joint injection, there is also a risk of infection — very low with proper sterile technique, at approximately 1:50,000.

Particularly important with Arthrosamid is a meticulous, strictly sterile, and precise injection technique, because the material remains in the joint permanently. This is precisely why I now perform all Arthrosamid injections exclusively with MRI navigation.

Encouragingly, the long-term follow-up data now available have not revealed any new notable safety signals. That said, the same principle applies here: any implant that remains permanently in the body must continue to be monitored scientifically over the long term.

Regenerate Instead of Operate?

When a patient with knee osteoarthritis sits in front of you, how do you decide which therapy is right for them?

That is the central question for me. A modern approach to osteoarthritis should not follow a rigid, one-size-fits-all protocol.

I take into account age, degree of osteoarthritis, quality of the remaining cartilage, axial alignment and joint stability, inflammatory activity, pain, function, athletic demands, and of course the patient's own expectations.

For mild to moderate osteoarthritis, for example, we frequently achieve very good results with high-quality hyaluronic acid and PRP. We also incorporate movement therapy, muscle strengthening, and, depending on the findings, physical modalities such as focused shockwave therapy or EMTT.

For more advanced osteoarthritis, Arthrosamid can be an attractive long-term option. Combination therapies or treatments coordinated over time are also possible.

Joint replacement remains an excellent treatment when it is truly necessary. My guiding principle, however, is this: as long as a joint can be functionally preserved with reasonable effort and the patient enjoys a good quality of life, all available options should be explored first. Surgery should not happen too early — but it should not be avoided at any cost either.

Are we witnessing a turning point in osteoarthritis treatment right now, or is the enthusiasm premature?

I do genuinely believe we are in the midst of a paradigm shift. We are increasingly moving away from the idea of simply prescribing painkillers for osteoarthritis, administering a few infiltrations, and eventually replacing the joint.

The future, in my view, lies in individualized, joint-preserving, and bioregenrative treatment concepts. These include biological approaches such as PRP, modern hyaluronic acids, hydrogels, and further regenerative therapies — guided by the motto: regenerate instead of operate!

Arthrosamid is particularly exciting in this context, because a single treatment can apparently remain effective for several years. The current five-year data are encouraging. Nevertheless, we should not let enthusiasm get ahead of the evidence. We need larger patient cohorts, further independent studies, and long-term comparative data.

Based on my own clinical experience, however, I would say this: hydrogels are not a passing trend. They have the potential to earn a well-established place in conservative osteoarthritis therapy — particularly when they allow us to preserve good joint function in patients over many years and avoid surgery, or at least delay it significantly.