Osteoarthritis: Which Injections Work – and Which an Orthopedic Specialist Questions
An injection for osteoarthritis pain – but which treatments actually make a difference? Orthopedic specialist Dr. Ferzan Süzer explains why she rarely uses cortisone for degenerative joint disease, what research reveals about hyaluronic acid and platelet-rich plasma, and why injections alone are not enough.
One injection into the knee and the pain subsides – that's how simple the promise of many osteoarthritis treatments sounds. But what works for one patient may do nothing for another. Osteoarthritis is not a single, uniform condition, and the available preparations differ considerably from one another.
This is especially clear with autologous blood therapy: the patient's blood is drawn and processed, and the resulting preparation is then injected into the affected joint. Yet even within the term PRP (platelet-rich plasma), there are different compositions and dosages. Study results therefore cannot simply be carried over from one preparation to another.
Dr. med. Ferzan Süzer, a specialist in orthopedics and trauma surgery and head of the private practice Regenera Berlin, explains why she does not routinely use cortisone for degenerative osteoarthritis, what biological therapies can and cannot offer, and why an injection alone is rarely the full solution.
Dr. Süzer, what factors determine which treatment makes sense for a patient with osteoarthritis?
Osteoarthritis is not, in my view, simply a "cartilage wear disease." Today we regard the entire joint as an organ: cartilage, subchondral bone, synovium, menisci or labrum, capsule, musculature, tendons, and the mechanical load on the joint are all interconnected. Add to this metabolic and inflammatory factors, as well as changes in pain processing in cases of long-standing pain.
What matters, therefore, is not solely the degree of osteoarthritis seen on X-ray or MRI. A focal cartilage defect, for example, is not automatically the same as clinically relevant, diffuse osteoarthritis. I want to understand where the pain is actually coming from. Is the joint in an inflammatory state – is there synovitis or an effusion?
Are there axial malalignments, instabilities, or meniscal or tendon problems? How strong is the musculature? How much mechanical load is involved? Is there excess weight, metabolic disease, or other factors driving chronic inflammatory processes?
The distinction between predominantly mechanically driven osteoarthritis and an inflammatorily activated form is also important. A warm, swollen joint with effusion presents a very different therapeutic situation from a low-irritation joint with symptoms that appear only under load.
That is why I approach osteoarthritis therapy like a modular system. The individual components must be combined on a case-by-case basis.Exercise, muscle building, weight management, improving biomechanics, regenerative or symptom-modulating injections, physical therapy, and surgical procedures where appropriate all have their place. Not every patient needs everything – and not every patient benefits from the same intervention.
Cortisone and Hyaluronic Acid: What the Expert Views Critically
How do you assess cortisone and hyaluronic acid injections for osteoarthritis?
Cortisone is not among the joint therapies I routinely use for degenerative osteoarthritis in my practice, and I do not routinely keep it on hand for that purpose.
In a strongly inflamed joint, cortisone can rapidly suppress the inflammatory reaction and provide short-term pain relief – and that is precisely where its strength lies. However, the effect is generally limited in duration. With repeated intra-articular use, there are also relevant discussions and data regarding possible negative effects on cartilage and other joint structures. On top of this come systemic effects such as temporary rises in blood sugar, as well as questions about infection risk and timing relative to a planned joint replacement.
My personal therapeutic approach to degenerative osteoarthritis is therefore more cautious. There are situations in which corticosteroids can be medically appropriate; however, as a recurring standard therapy for a chronic degenerative joint disease, they do not fit my concept of long-term joint preservation.
My view of hyaluronic acid is more nuanced. Here too, the same principle applies: hyaluronic acid is not all the same. Preparations differ in molecular weight, chemical cross-linking, concentration, volume, and injection regimen, among other things. There are linear, high-molecular-weight, cross-linked, and combination preparations of varying molecular weights.
That is why I find the blanket question "Does hyaluronic acid help?" just as problematic as the question "Does PRP help?" The evidence base is heterogeneous, and various international professional societies reach different conclusions. At the same time, in clinical practice there are patients who benefit significantly from it for months at a time.
Age alone is also not, in my view, a sufficient basis for selection. What matters more is the osteoarthritis phenotype, the condition of the joint, inflammatory activity, the mechanical situation, and the patient's prior treatment history.
Another treatment option is autologous blood therapy. What should patients know about procedures such as PRP?
The term "autologous blood therapy" is actually far too nonspecific. A wide variety of preparations can be made from a patient's blood, and depending on the processing method, they differ considerably in platelet concentration, plasma content, leukocytes, erythrocytes, fibrin, and therefore also in the growth factors and cytokines they contain.
That is precisely why PRP is not all the same. There are leukocyte-poor and leukocyte-rich preparations, different centrifugation methods, different starting and final volumes, and very different platelet doses. Even the number of injections and the intervals between them vary from protocol to protocol.
Platelets do not only serve blood coagulation. They contain numerous signaling proteins and growth factors that can influence inflammatory processes, cell communication, and tissue regeneration, among other things. However, the assumption that more platelets automatically produce a better preparation is an oversimplification. More recent research increasingly suggests that composition and dose are probably just as important as platelet concentration alone.
Several manufacturers have developed different processing systems for this purpose. From a scientific standpoint, one must therefore always look carefully at which preparation was actually used in a given study. The results of one particular PRP protocol cannot simply be applied to every other autologous blood preparation.
There is an additional point that will likely become increasingly important in the future: the source material is the patient themselves. Age, metabolic health, obesity, diabetes, medications, and systemic inflammatory processes can all influence the composition of the blood and therefore, in theory, that of an autologous preparation as well. However, the extent to which this affects clinical treatment outcomes has not yet been sufficiently clarified.
When does the effect set in, how long does it last, and how many injections are needed?
There is no single answer to that question. Biological procedures are not primarily a form of instant pain relief. Some patients report improvement within just a few weeks, while in others the effect develops more gradually.
For knee osteoarthritis, where the strongest evidence base exists, many studies show meaningful improvements in pain and function over several months – in some cases up to around twelve months or beyond. At the same time, there is considerable variability between studies and between individual patients.
The optimal number of injections has not been definitively established either. Depending on the preparation used, single injections or a series may be administered. More is not automatically better. What matters is the preparation, the stage of disease, the joint involved, inflammatory activity, and the patient's individual baseline situation.
I therefore do not make any guarantees or promise a fixed duration of effect. The goal is a clinically meaningful improvement in pain, function, and resilience, so that the patient is able to train more effectively and stabilize the joint more actively.
At what stage of osteoarthritis are biological therapies appropriate?
The most convincing evidence currently exists for mild to moderate osteoarthritis, particularly of the knee. In early and intermediate stages, the condition of the joint still allows pain, inflammation, and function to be meaningfully influenced in many cases.
In very advanced osteoarthritis with significant joint destruction, pronounced malalignment, or a nearly obliterated joint space, expectations need to be framed in a considerably more realistic way. Even then, individual patients may experience symptomatic benefit – but an injection cannot restore a destroyed joint architecture.
It is therefore important to me not to base treatment decisions solely on a radiological classification. A patient with pronounced radiological changes can function surprisingly well, while another with moderate imaging findings may have considerable pain and synovitis.
The optimal indication emerges from combining imaging findings, clinical examination, inflammatory activity, biomechanics, function, and the patient's individual goals.
What risks and side effects can occur with autologous blood and hyaluronic acid injections?
Biological procedures are not risk-free wellness treatments. After intra-articular injections, temporary pain, swelling, or a local inflammatory reaction can occur. Infections are rare but represent a potentially serious complication of any joint injection. Sterile technique and a clear indication are therefore essential.
With autologous blood preparations, allergic reactions to the preparation itself are naturally far less of a concern than with foreign substances. However, differently composed PRP products can trigger different inflammatory reactions.
With hyaluronic acid as well, local irritation can occur. Certain more heavily cross-linked preparations have been reported more frequently in association with pronounced inflammatory reactions.
Before any injection, concurrent illnesses, active infections, anticoagulant medications, and other individual risk factors must also be taken into account.
Why Muscle Training Remains Indispensable in Osteoarthritis
What role do exercise, strength training, and body weight play?
An injection cannot replace training. Muscle strength is one of the most important modifiable factors in joint function. A well-trained muscular system reduces peak loads, improves joint guidance, and increases resilience.
For patients with excess weight, weight reduction also plays a key role. This is not simply a matter of reducing mechanical load. Adipose tissue is metabolically active and produces inflammation-relevant signaling molecules, among other things. It is therefore becoming increasingly clear that metabolic and inflammatory osteoarthritis phenotypes exist as distinct entities.
This is where the concept of "joint longevity" comes into play for me. We should not wait to treat until a joint is maximally damaged. The goal should be to preserve joint function, muscle strength, and mobility for as long as possible, while simultaneously addressing modifiable risk factors.
This includes exercise, strength training, body weight, metabolic health, and the treatment of relevant deficiency states. With chronic pain, we must also recognize that over longer periods the nervous system and pain processing can become altered. In such cases, treating the structure within the joint alone is often no longer sufficient.
What People with Early Osteoarthritis Should Do
What is your most important piece of advice for people who have just been diagnosed with osteoarthritis?
Don't wait until the joint is severely restricted. Early osteoarthritis is precisely not the moment for "You'll just have to live with it – come back when you need a prosthesis."
There is a great deal we can influence at an early stage. It starts with an accurate diagnosis. Where is the pain coming from? Is there a focal cartilage defect, early diffuse osteoarthritis, a meniscal pathology, an instability, an axial problem, or an inflammatory component?
An individualized treatment concept should then be developed. I like to call this joint longevity: the aim is not only to treat the current pain, but to preserve the joint's function for as long as possible.
Research in the field of biological procedures is currently advancing very rapidly. Guidelines provide an important framework, but by their very nature cannot immediately reflect every new development, since their creation and consensus processes take time. On the other hand, a single new study or conference presentation does not automatically mean that a universally applicable treatment recommendation can already be derived from it.
For me, therefore, the right approach combines several elements: staying current with international research, knowing the guidelines, critically evaluating the quality of the evidence, and then making an individualized decision together with the patient.
Osteoarthritis is not all the same. Hyaluronic acid is not all the same. And autologous blood preparations are not all the same. Making these distinctions is, in my view, one of the most important developments in modern conservative osteoarthritis therapy.
