Stem cells / BMAC / fat

No proof these injections restore worn cartilage.

Illustrative laboratory specimen processing with a microscope — Illustrative laboratory scene · products and evidence differ

What could it help with?

Cell-based injections may modestly improve knee pain and function, but the 2025 Cochrane review rated that evidence low certainty. Marrow concentrate, processed cells, and fat preparations are not interchangeable. [1][2][3]

Who might it suit?

For: Understanding claims about marrow concentrate, stem cells, and microfragmented fat.

Not for: Routine treatment of advanced hip or knee OA.

Limits and important cautions

Structural benefit and important harms remain uncertain. No evidence here establishes regrowth of an arthritic joint or validates every commercial preparation.

What happens, how long, and what could it cost?

What happens: First identify the exact material and processing. Marrow concentrate, fat preparations, and processed cells are different.
When might I notice a change?: A reliable personal timeline cannot be predicted from the evidence reviewed here. Agree on a review date before starting.
How long might benefit last?: Benefit and durability depend on the exact intervention and population. The evidence section below explains what is known.
Repeat treatment: Do not assume a package of repeat procedures has proven benefit.
Activity and recovery: Ask who provides follow-up, what symptoms need urgent attention, and what restrictions apply to you.
Ask for a complete estimate: Harvesting if applicable, processing, injection, imaging guidance, follow-up, and treatment of complications.

Use this as a consultation guide. A timeline is not a guarantee; the evidence and FDA sections below remain part of the decision.

Compare expectations side by side ↗

THE EVIDENCE IN CONTEXT

Possible symptom benefit; low certainty

Read the 3 selected references

Whittle et al.: stem-cell injections for knee OA ↗Systematic review · Cochrane · 2025
25 trials: low-certainty evidence of modest pain/function improvement; safety and structural effects uncertain. Cell sources and processing varied.
AAHKS: biologics in advanced hip and knee arthritis ↗Society position statement · 2025
Does not support routine biologic injections for advanced disease. This scope differs from trials in milder knee OA.
FDA: regenerative medicine products ↗Regulatory safety guidance · Current guidance
Addresses unapproved orthopedic claims and safety concerns. Regulatory status is separate from the size of any clinical effect.

Editorial synthesis · reviewed September 19, 2026. These are selected decision-relevant references, not an exhaustive systematic review or a new formal evidence grade. FDA status and coverage are assessed separately.

FDA status

Not approved for osteoarthritis

FDA states that regenerative medicine therapies have not been approved for orthopedic conditions such as osteoarthritis. Processing-device clearance or use of your own marrow or fat is not approval of a joint-repair claim. Regulatory requirements depend on the exact product and processing.

FDA: regenerative medicine warning ↗

Site summary of FDA information · reviewed September 19, 2026. Refer to current product labeling. This is not an FDA endorsement of this site.

What do professional guidelines say?

AAHKS: AAHKS does not recommend routine biologic injections for advanced knee or hip arthritis. They have not been shown to restore cartilage.

ACR: Strongly recommends against stem-cell injections for knee and hip OA.

Will Medicare cover it?

No routine OA coverage.

How we interpret changing evidence