The Full Answer
Most orthobiologic injections (PRP, stem cell/BMAC) go into the joint space itself — the fluid-filled area between bones. An intraosseous injection is different: a small drill or needle creates a channel through the outer bone (cortex) so the injectate can be delivered directly into the bone marrow, at the site of a bone marrow lesion (BML) seen on MRI. It's typically done under fluoroscopic or ultrasound guidance, using local anesthesia, in an outpatient procedure room rather than an operating room.
What the Current Evidence Shows
The technique was introduced by Spanish researcher Mikel Sánchez and has since been studied by several groups, including Philippe Hernigou's long-running work on bone marrow concentrate dosing. A 2021 systematic review concluded knee intraosseous injections are minimally invasive, safe, and show real short-term benefit, while noting that larger, longer-term trials are still needed.
Who May Benefit
Patients with an MRI-confirmed bone marrow lesion underneath damaged cartilage — most often in knee osteoarthritis — particularly when pain seems out of proportion to what the cartilage alone would explain. It's generally considered alongside, not instead of, an intra-articular injection.
When Surgery May Be More Appropriate
Once a joint is bone-on-bone or has significant structural collapse, an intraosseous injection has little biologic target left to work with, and joint replacement becomes the more reliable option.
Dr. Tortland's Perspective
Dr. Tortland has performed fluoroscopy-guided intraosseous PRP injections for bone marrow lesions in the medial femoral condyle and tibial plateau, and has taught the technique directly to visiting physician fellows. His consistent point: technique only matters if the biologic dose delivered is adequate — an underdosed injection, IO or otherwise, is unlikely to help.