Osteoarthritis constitutes a real “public health problem“, estimates Dr Laurent Grange, rheumatologist at CHU Grenoble-Alpes: “5% of the population suffers from knee osteoarthritis, a pathology with a considerable impact on patients’ quality of life“, he warns. Over the years, the cartilage that covers the ends of the bones at the joints cracks and thins. Result? The pain is severe and the swelling is significant. And if painkillers and cortisone infiltrations have long been favored as treatment, new minimally invasive techniques now seem to appeal to more and more patients wanting to put an end to the pain.
Freezing nerve endings
Performed on an outpatient basis under local anesthesia, this technique relieves pain with cold. It consists of applying very low temperatures (from -20 to -70°C) to certain sensitive nerve endings in the knee. In fact, a radiologist temporarily interrupts the transmission of the pain signal to the brain.
Vessel embolization
Originating in Japan, this technique aims to obstruct the small branches of the arteries responsible for inflammation. Concretely, a catheter is inserted in the groin or foot, then guided to the targeted vessels using a contrast product (fluoroscopy). The practitioner then injects tiny microparticles to block these vessels.
The advantages of this method? It is painless, leaves no scar and can be performed without hospitalization.
Injecting a solution into the joint
In France, two other approaches are used to relieve osteoarthritis: the injection of polyacrylamide hydrogel (Arthrosamid) and that of hypertonic dextrose, called prolotherapy.
- The hydrogel acts here as a substitute for synovial fluid: it integrates with the joint tissue and reproduces its properties;
- Prolotherapy, for its part, works through an indirect mechanism: dextrose causes slight local irritation, triggering a (moderate) inflammatory response which promotes tissue repair.
TENS electrostimulation for pain
Low frequency nerve stimulation (TENS) is also often mentioned: by sending weak electrical impulses through the skin, this technique modulates the transmission of pain to the brain.
Our expert’s opinion on these minimally invasive techniques
If these methods seem to combine good points by reducing the suffering of patients while allowing them to avoid surgery, not all of them should be adopted.
“Not all available techniques appear in national recommendations: studies are often small and limited; their results cannot therefore be generalized. In other words, it is not recommended to use them in routine practice. Only one trial exists for embolization of knee arteries. warns Dr. Laurent Grange.
However, some methods are interesting and seem effective,”because they block the structure responsible for pain“, says the doctor.
One of the most promising techniques is based on GPL-1 (Glucagon Like Peptide-1) analogues. “This molecule has an analgesic, symptomatic and structural effect, which helps slow down tissue destruction. It is already giving encouraging results. confides the expert, before continuing: “Other techniques, such as radiofrequency or embolization, seem relevant but should not be generalized for the moment, because they still remain at the research stage.
But none of these processes are miraculous. “Whatever the technique chosen, the benefit/risk ratio must be carefully evaluated. Certain interventions can be potentially dangerous: for example, poorly performed embolization can obstruct a vessel. Cryoneurolysis, which consists of “grilling” the nerve responsible for the pain, can also damage other areas/nerves. Larger studies are therefore necessary before these techniques are recognized in good practice recommendations”, concludes the rheumatologist at Grenoble University Hospital.