Red zone
A red-zone tear at the outer edge can mend.
Blood reaches it, so a small tear can knit with rest and rehab, and a larger one can often be stitched (a meniscus repair).
Can a meniscus tear heal without surgery? Some can, and your MRI says which.
You're probably reading this the night after the MRI, with "tear" in the report and an arthroscopy on offer. Whether it heals depends on where the tear sits and what shape it is. At Hospital Angeles in Tijuana, 25 to 30 minutes from San Diego, the physician team reads your MRI and says plainly which tear you have, and whether an image-guided injection fits it or a surgeon should take it.
Ten questions, no email, no call. The result names a sensible next step for your knee.
Nothing trimmed out
No meniscus is cut away. Cells go into the joint and the tissue around it, under live imaging.
24 to 72 hours of soreness
Then physical therapy, and check-in calls at 1 week, then at 1, 3 and 6 months, then once a year, from home.
Which meniscus tears heal on their own, and which do not.
Each knee has two menisci, C-shaped pads of cartilage between the thigh bone and the shin bone. Only the outer edge has a blood supply: Arnoczky and Warren mapped it in 1982 (American Journal of Sports Medicine), vessels reaching the outer 10 to 30% of the medial meniscus and less of the lateral. That strip is the red zone; the rest is the white zone.
- Red zone. The outer band, where blood reaches.
- White zone. The inner part, with little or no blood.
- Shin bone (tibia). The menisci sit on top of it.
Red zone
White zone
A white-zone tear in the inner part usually stays a tear.
With no blood supply it has little to mend with. This is the tear most often trimmed.
Degenerative
A degenerative meniscus tear arrives without a twist.
Wear rather than an injury, often with early arthritis. In Englund's 2008 study (New England Journal of Medicine), 61% of middle-aged and older adults with a tear on MRI had no knee pain that month.
Bucket-handle
A bucket-handle tear flips a flap into the joint.
The knee catches or will not straighten: a mechanical block no injection moves.
Your MRI report names where the tear sits and its shape. Ten questions point you to a sensible next step for it.
Find your next step →Who is a candidate for a stem cell injection for a meniscus tear, and who is not.
"The other doctors told me that after physical therapy, if that didn't work for me, they only suggested surgery." That's Kathie M., 67, a Celva patient with a torn anterior meniscus. A tear that doesn't match where the knee hurts is a reason to keep looking, not a reason to inject.
Strong fit
A degenerative tear in a knee with early to moderate arthritis.
Kellgren-Lawrence grade II to III (the standard X-ray scale for knee arthritis), joint space still there in at least one compartment, physical therapy behind you. The profile we accept most often.
Also a fit
A tear where therapy plateaued and cortisone did not hold.
Pain that physical therapy eased but never cleared, and an injection that wore off.
Also a fit
A knee that changed after an earlier tear or a scope.
Wear that sped up after an injury or an arthroscopy. Cells do not regrow removed meniscus; the physician team reads what is left.
Not a fit
A bucket-handle tear locking the knee, or a ligament that needs rebuilding.
A knee that locks and will not straighten, or gives way from a torn ligament, is a surgeon's case, and we recommend one we trust. A knee that turns hot, red and swollen with a fever, or one you cannot stand on after an injury, is an emergency: go to an emergency room today.
Candidacy is confirmed from your imaging and the call. When you arrive, the physicians examine you in person to plan exactly how the treatment is done on your knee.
What a stem cell injection for a meniscus tear looks like, most patients home the same day.
About 4 hours at the hospital, 15 to 30 minutes on the table, every placement under live imaging: fluoroscopy (a live X-ray) or ultrasound.
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Picked up in San Diego
Over the border, 25 to 30 minutes from San Diego.
A Celva driver picks you up anywhere in Southern California and crosses the border with you. 1 or 2 companions are welcome, never required. The physicians examine the knee in person first to plan the injection.
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Local anesthetic, sedation optional
Still, comfortable, no general anesthesia.
Local anesthetic always, twilight sedation if you want it, and Dr. Rocio Ambrosio Nuño, anesthesiology, in the room.
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Needle under live imaging
Into the joint, and the tissue that holds it.
Cells go into the joint space and into the tendons, ligaments and muscles around the knee, each placement confirmed on screen. They are designed to support that tissue, not to regrow a meniscus.
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The cells
Matched to your knee, not pulled off a shelf.
Bone-marrow and umbilical-cord MSCs (mesenchymal stem cells), sometimes with chondrocytes (cartilage cells), from a screened donor, grown in the on-site cGMP-compliant lab and released after 6 lab tests. Almost every joint patient also receives a systemic IV the same day.
Not sure your knee is this knee? Ten questions, no email, and the result names a next step.
Find your next step →Meniscus surgery alternatives: arthroscopic trimming versus an injection.
Trimming (arthroscopic partial meniscectomy) is the operation most tears are offered. The trials below are why it is no longer automatic.
Watch Dr. Kirk Lewis's story"I ended up having surgery twice on my knee. I had torn meniscus in my knee."
- The torn part, cut away.
- The camera (arthroscope).
- The shaver that trims it.
- The meniscus, left in place.
- Cells placed in the joint.
- One needle, under live imaging.
The question
Arthroscopic trimming
Image-guided injection
What is done to the meniscus
The torn part is cut away through small incisions and removed
Cells placed into the joint and the tissue around it. Nothing removed
What it cannot change
Meniscus that is removed does not grow back
A flap locking the knee, or meniscus already removed
When it is the right answer
A locked knee, or a bucket-handle tear. A young knee's red-zone tear is usually stitched instead
A degenerative tear in a knee with early to moderate arthritis, after therapy has plateaued
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6 months
Katz, New England Journal of Medicine, 2013. 351 patients with a tear and mild to moderate arthritis: trimming plus therapy against therapy alone. Function improved about the same.
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12 months
Sihvonen, New England Journal of Medicine, 2013. 146 patients with a degenerative tear: trimming against a sham operation. The trimmed knees did no better.
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2 years
Kise, BMJ, 2016. 140 middle-aged patients: 12 weeks of supervised exercise against trimming. No clinically relevant difference.
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21 years
Roos, Arthritis & Rheumatism, 1998. Knees whose meniscus was removed in an open operation, against matched knees: arthritis on X-ray about 14 times as common.
The honest limit: none of these trials tested cells. They show what trimming does for a worn knee, and why a 2017 guideline in the BMJ advises against arthroscopy for nearly all degenerative knees, not what an injection will do for yours. A locked knee, or a young knee with a tear that can be stitched, belongs to a surgeon.
Recovery after a meniscus injection: a knee answers in months, not days.
No promises about outcomes. A schedule somebody keeps: four calls in the first 6 months, then one a year, from home, each measured against where you started.
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1 week
Soreness first. Then a call.
Soreness for 24 to 72 hours, then 7 to 10 days of very limited activity before physical therapy. At 1 week your patient coordinator or aftercare specialist calls, by phone or video, and a physician joins when needed.
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1 month
Too early to judge, and we say so.
The cells work slowly, through signaling to nearby tissue (paracrine signaling). This call checks how you're settling. Treatment is one session, not a course.
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3 months
The first fair read.
The call asks about what you told us at the start: stairs, kneeling, getting up from a chair.
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6 months
The read that counts.
This call compares you with where you started. Whether a second treatment makes sense is decided at these reviews.
Every one of those calls is measured against the first one: the MRI and the knee you bring to it.
Find your next step →Four steps for your meniscus tear, and the physician team decides at the third.
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Call
A patient coordinator, about 15 minutes.
A coordinator typically calls within 1 business day, takes your history and tells you what to send.
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Records
What you already have.
Your MRI report and what has been tried.
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Review
The physician team reads it.
Your MRI against where the knee hurts: candidate or not, and which tissue to treat.
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Plan
A written plan, then a date.
A written answer, with a plan and an itemized quote for your case.
Steps 1 and 2 are the only ones you do. Take the call, send the report, and the rest is ours.
Book a call →Stem cell knee injections in Tijuana, done inside a hospital.
Most cell therapy in Mexico happens in small, standalone clinics. Celva operates inside Hospital Angeles Tijuana, a 116-bed private hospital in the Angeles Health network, one of Mexico's largest. The physician team, the anesthesiologist and hospital imaging are in the building for your session.
Medical Director
Dr. Cesar Amescua, MD
Anesthesiology & Sedation
Dr. Rocio Ambrosio Nuño, MD
Interventional Radiology
Dr. Alejandro Castillo, MD
Anesthesiology & Pain Medicine
Dr. Melina Mariscal, MD
The physicians on every chart. Full bios →
Ask any clinic who is in the building during your injection. Then ask us.
Find your next step →Meniscus tear questions, answered.
My MRI says "degenerative tear." Did I injure my knee?
Usually not in a single moment. A degenerative tear is fraying that builds with age and use, often alongside early arthritis, and it can show up on a scan years before it causes pain. That is why the physician team reads the MRI against where the knee hurts, not the word "tear" on its own.
I already had an arthroscopy. Can I still be treated?
Yes, a knee after a scope is evaluated like any other. Cells do not regrow meniscus that was removed, so the physician team reads what is left: the remaining meniscus, the cartilage, and the tendons and ligaments around the joint.
Should I try physical therapy first?
If you have not, yes. In the Kise trial above, supervised exercise did about as well as trimming for a degenerative tear over 2 years. The call starts with what you have already tried.
Can both knees be treated on the same day?
Yes. Two knees are treated in the same day, with more physician time and a larger total dose. The physician team reads both MRIs first and answers for each knee separately.
Do I need a new MRI before we talk?
No. Send the MRI report you have, the images if you can get them, and a list of what has been tried. If the imaging is old or the physician team wants a closer look, MRI, X-ray, ultrasound and CT are in the same building at Hospital Angeles, and the knee can be imaged during your visit.
The physician team. Your MRI. A straight answer.
Start with 10 questions, no email asked. When you want a person, the first call is with a Celva patient coordinator, about 15 minutes, and the physician team answers in writing: a candidate for cells, or a knee that belongs with a surgeon.
These therapies are not FDA-approved. Treatments are performed in Mexico by licensed physicians in a hospital setting. Individual results may vary. Not medical advice.