Stem Cell Injections in Orthopedics: What Actually Works

Stem cell therapy for orthopedic conditions has become one of the most marketed — and most misunderstood — treatments in modern medicine. Patients are bombarded with claims of cartilage regeneration, “avoidance of surgery” and miraculous recoveries, often at significant out-of-pocket cost. The reality is considerably more measured. This article explains what is actually being injected, what the evidence does and doesn’t support, and how stem cell treatments fit into orthopedic practice today.

What is actually being injected?

The term “stem cells” covers a wide range of products. In orthopedic practice the most common are:

• Bone marrow aspirate concentrate (BMAC) — bone marrow is harvested from the iliac crest, spun in a centrifuge, and the concentrate is injected. It contains mesenchymal stromal cells (the precursor cells often called “stem cells”), platelets, growth factors and other healing-related signalling molecules.
• Adipose-derived stromal vascular fraction — fat is harvested by a small liposuction, processed, and the stromal vascular fraction injected. Higher cell yield than BMAC.
• Cultured mesenchymal stem cells — cells from bone marrow or other sources are isolated and expanded in laboratory culture. In many countries (including India), the regulatory framework is restrictive; this is not routine clinical practice.
• Amniotic-derived products — sourced from amniotic membrane and fluid. Contain growth factors but very few or no live stem cells in most commercial preparations despite marketing claims.

What the evidence shows

The honest answer is: some evidence for some conditions, but the field is far less developed than the marketing suggests. The cleanest evidence is for:

• Knee osteoarthritis — BMAC has shown moderate benefit in early to moderate arthritis in several trials, comparable to or slightly better than PRP. Cartilage regeneration on imaging is not consistently demonstrated; pain and function improvements are.
• Selected cartilage defects — focal defects in young patients may benefit from combined surgical and cell-based approaches (matrix-assisted procedures).
• Selected tendinopathies — some evidence in refractory cases.

Evidence is weak or absent for use in end-stage arthritis, complete ligament tears, and most other indications for which the treatment is widely advertised.

Why marketing outpaces science

Three reasons: the cells themselves are not patentable, so there is limited pharma incentive to fund the large rigorous trials that would settle the question; the products are expensive, creating commercial incentive to provide them; and patients have legitimate desperation, particularly when facing surgery, which makes them receptive to alternatives.

Cartilage regeneration: the difficult truth

True regeneration of degenerated articular cartilage in the adult human has not been reliably demonstrated by any current injection-based treatment. Imaging studies after injection treatments rarely show meaningful cartilage thickening or quality change. What injection treatments do achieve, when they work, is symptom modification — pain reduction and improved function — which is genuinely valuable but is not the same as regrowing cartilage.

How to think about it as a patient

If you are being offered stem cell therapy, the questions to ask are:

• What specifically is being injected — BMAC, SVF, amniotic product?
• What does the published evidence say for my exact condition and stage?
• How does this compare in cost-effectiveness to PRP or established treatments?
• What is the realistic expected duration of benefit?
• Is this part of a structured plan with rehabilitation, or a standalone treatment?

Our approach

We offer BMAC as a regenerative option for selected patients with mild to moderate arthritis who have failed conservative care and want to extend the window before surgery. We are honest that the evidence is moderate rather than strong, and we combine it with structured rehabilitation. We do not recommend it for end-stage disease or for indications without supportive evidence.