Lana et al. - Pulsed radiofrequency neuromodulation of subchondral bone in knee osteoarthritis
In knee osteoarthritis, MRI often shows “bone marrow lesions”: areas of damaged, swollen bone just beneath the cartilage. These lesions are linked to pain and to faster disease progression, yet no approved treatment targets them with a lasting structural effect. The authors propose placing a PRF electrode directly into this bone, through a thin needle under image guidance, to relieve pain and shrink the lesion. The article is a hypothesis paper.
Key points
- The bone’s own nerves may be the target. The bone under the cartilage contains pain-sensing nerves. In mouse studies, these nerves do more than signal pain: they also help regulate how bone is broken down and rebuilt. The authors propose that PRF applied at these nerve endings could calm pain signalling and shift remodelling toward healing. They state clearly that this circuit has been shown in animals but not yet in human osteoarthritic bone.
- An electrode inside the bone delivers more energy where it matters. External pulsed electromagnetic field (PEMF) devices produce weak, diffuse fields in bone. A PRF electrode produces fields at least 10,000 times stronger, concentrated within millimetres of its tip. The only human precedent is one small, uncontrolled series of 10 patients with hip osteonecrosis. That series shows the procedure is technically feasible but does not establish safety or effectiveness. The authors suggest that low-heat pulse patterns such as STP or PRF with lower duty load (such as 3 or 5Hz, 5 ms), from the Leiden-Nice consensus, may limit heating in bone and they mention RedoxPRF as a possible second mechanism.
- A built-in contradiction will decide the outcome. Nerve growth factor (NGF) is the proposed messenger, and it seems to work in opposite directions:
- In dead or damaged bone (osteonecrosis), more NGF appears to support repair.
- In osteoarthritis, NGF increases pain. Blocking it relieves pain but can worsen bone and cartilage.