Keywords: Stem cells, arthritis, arthroscopy, knee anatomy, Luka Doncic
Reports say Celtic guard Kemba Walker recently underwent a stem cell knee injection. As a physician, I'm in my "lane" but no expert on stem cell injections. Let's go under the hood.
First, a little about knee arthritis, a source of pain, joint swelling (effusion), warmth (from inflammation), and loss of function. Severe arthritis is common with about 700,000 total knee replacements performed annually in the US.
Here's an x-ray image of the right knee. On the right image, see the loss of the "joint space" (cartilage is invisible on plain x-rays) and the "subchondral sclerosis" (white stuff/bone hardening under the cartilage) on the abnormal (bone on bone) knee.
What are stem cells? Stem cells are immature cells formed in bone marrow and other tissues that transform into "more specific" tissues. We are NOT talking about embryonic stem cells.
Stem cells are being used or studied in over fifty diseases, ranging from cancer, to immunologic disorders and deficiency, anemias, heart disease, neurologic conditions, and arthritis.
Where are they harvested? "Mesenchymal stem cells, which can make bone, cartilage, fat, fibrous connective tissue, and cells that support the formation of blood can also be isolated from bone marrow." Most commonly stem cells come from blood or bone marrow.
How are they harvested? Depending on the intended treatment, stem cells can be "harvested" from the bone marrow, blood, fat, and other tissues. They can be from the patient themself (autologous stem cells) or other individuals (allogeneic). Most commonly they are obtained from bone marrow (drilling into the bone) or blood samples. They are then processed from bone marrow with a variety of separation techniques.
How is it supposed to work? The theory is that stem cells decrease inflammation, slow damage, and repair cartilage. That's a euphemism for we don't know. Studies show effects on cellular (T cell immunity), antibody formation, and on dendritic cells that participate in immunity. Doctors don't know the best dose, frequency of treatment, or overall effectiveness of the treatment. "Most studies have suggested that MSCs primarily regulate local inflammation, apoptosis and proliferation of cells through paracrine mechanisms, rather than directly differentiating into chondrocytes to participate in tissue repair." In lay terms, they reduce inflammation, yet don't magically allow cartilage to heal itself.
What are the side effects? The treatment can cause pain and swelling. Because most of the time they are from your own supply, there shouldn't be "rejection" risk. Any time you pierce the skin, infection risk exists.
What do studies report? First, we should be aware that there is a general bias to report studies that show effectiveness, not failure. We should also know that stem cells are injected with "other stuff," like hyaluronic acid (a lubricant), platelet-rich plasma, and/or fibrin gel. Just as in a "pill" there is 'active ingredient' and filler, but the filler may exert effects, too.
How much does it cost? The cost varies and is not reimbursed by insurance for joint pain management as it is considered experimental. The cost is said to be between $5,000 and $50,000 dollars. That said, it's not likely to be something for most of us.
...from the underrated Finding Forrester.
Will it work for Walker? "Not exactly a soup question."
Lagniappe: SLOB 'diversion' from Chris Oliver.
Simple can be more effective.
— Chris Oliver (@BBallImmersion) December 1, 2020
The stagger makes it seem like the action is going high but a ball side flash to the low corner with everyone spaced high creates an isolation on this sideline inbound play that worked. pic.twitter.com/GYkvovcVS6
Lagniappe 2: Luka Doncic film study. Why it works...
Terrific breakdown. Fundamental. Simple. Consistent. Attention to detail.