By Vivonyx · Last reviewed: October 2026
A torn rotator cuff can make everyday things hard: reaching a shelf, sleeping on your side, lifting a bag. If you've been reading about stem cells for shoulder tears, you've probably landed on one big question: can stem cells help a torn rotator cuff heal?
This article walks through what the human studies actually tested and found. It's education, not medical advice, and it isn't a recommendation for or against anything. New to all this? Our Start Here page covers the basics.
The rotator cuff in one minute
The rotator cuff is a group of muscles and tendons that holds the top of the arm bone in the shoulder socket and controls how the shoulder moves [1]. A tear can happen suddenly, such as in a fall, or slowly as a tendon wears down over time [1]. A partial tear doesn't go all the way through the tendon. A full-thickness tear does [1].
Rest and physical therapy may help some partial tears, while surgery to reattach the tendon may be needed for a complete tear [1]. But repairs don't always hold. Researchers describe retear rates after repair as "unacceptably high" [2]. That's the gap stem cell research is trying to fill.
Two very different questions
Studies use cells in two main ways, and the evidence is different for each:
Added during surgery. The surgeon repairs the tendon as usual, then places cells where the tendon meets the bone. The question: does the repair heal better?
Injected instead of surgery. Cells go into or near the torn tendon, with no repair. The question: can the tendon heal without an operation?
The cells vary, too. Many studies use bone marrow concentrate, drawn from the hip bone and concentrated during the same operation [4]. Others use mesenchymal stromal cells (MSCs) taken from a person's own fat tissue [2]. Our science page explains what MSCs are, and Wharton's Jelly vs. Bone Marrow Stem Cells compares the main sources.
Two ways cells have been studied for rotator cuff tears. Educational summary of the sources cited in this article.
Added during surgery: what the studies found
A French study compared 45 people who got bone marrow concentrate during repair with 45 matched people who didn't [3]. By six months, all 45 repairs in the cell group had healed, versus 30 of 45 without cells. At ten years, 39 of 45 cell-group repairs were intact, versus 20 of 45 [3]. Striking, but it wasn't randomized, so the groups may have differed in other ways.
A U.S. randomized trial assigned 91 people to repair with or without bone marrow concentrate [4]. On MRI at one year, retears showed up in 57% of the repair-only group and 18% of the cell group. Yet function scores improved in both groups, and the cells largely didn't improve them further. Treatment failed for seven people in each group [4].
A matched study of 70 people using fat-derived MSCs found the same pattern: fewer retears on MRI (14.3% vs. 28.5%), but no differences in pain, motion, or function scores at about 28 months [5].
Pooled reviews agree. One combined five studies with 415 people: retear rates were 17.7% with cells and 35% without, while pain and function were similar [6]. Another found no difference in clinical outcomes, a possible protective effect against retears, and called the evidence "preliminary" [2]. In a third review, no study reported complications from bone marrow concentrate, though methods varied widely [7].
So the honest summary: repaired tendons often looked better on scans, but people didn't clearly feel or function better than with repair alone, at least over the follow-up so far.
A related idea, drilling tiny holes in the bone to let marrow cells seep out, didn't pan out: seven randomized trials with 576 people showed no difference in retears or shoulder scores [8].
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Injected instead of surgery
The evidence here is earlier. A first-in-human study gave MSC injections from fat tissue into the tendon of 20 people with partial-thickness tears [9]. It reported no adverse events, plus less pain and smaller tendon defects on imaging. But it was mainly a safety and dosing study, with no comparison group.
A U.S. randomized trial of 51 people compared bone marrow concentrate plus platelet injections with a home exercise program [10]. The injection group reported bigger improvements at three months. But the comparison was exercise, not a placebo injection, and the exercise group could switch to injections after three months. The authors also reported financial ties to the company that offers the procedure [10].
Where PRP fits
PRP (platelet-rich plasma) is made by spinning a person's own blood and collecting the platelet-rich part [11]. A Cochrane review found no meaningful difference in long-term function when PRP was used during rotator cuff surgery, rated the evidence very low quality, and noted that preparation methods weren't standardized [11]. A later pooled analysis of 17 randomized trials found fewer retears when platelet products were added to repair (19.3% vs. 25.4%), with results depending on the type of preparation [12]. Our knee article compares stem cells and PRP in more depth.
FDA status and new trials
The FDA says regenerative medicine products, including stem cell and exosome products, have not been approved for any orthopedic condition, including tendonitis and shoulder pain [13][14]. Our guide Is Stem Cell Therapy FDA Approved? explains what approval means.
ClinicalTrials.gov lists about two dozen rotator cuff studies involving stem cells [15]. One example is a small South Korean safety study of donor umbilical cord MSCs added during repair of large tears, planning about 15 people [16]. A listing doesn't, by itself, mean a product is approved or legally marketed [13].
What we still don't know
Whether a better-looking MRI means a better shoulder over the long run.
Which cell source, dose, or preparation works best. Methods vary widely [7].
Whether injections alone help, especially for full-thickness tears. Controlled data are thin.
Long-term safety in larger, independent trials.
Frequently asked questions
Can stem cells help a torn rotator cuff heal? When cells were added during surgery, several studies found fewer retears on MRI, but pain and function were similar to repair alone [4][6]. Evidence for injections without surgery is early [9][10].
What kind of "stem cells" are used? Most studies used bone marrow concentrate from the hip or MSCs taken from fat tissue [2]. These are different products.
Is PRP the same as stem cell therapy? No. PRP is a concentrate of platelets made from your own blood [11]. Its rotator cuff research is mixed [11][12].
Is stem cell therapy FDA-approved for rotator cuff tears? No. The FDA says regenerative medicine products haven't been approved for any orthopedic condition, including shoulder pain [13][14].
Still have questions?
Shoulder headlines often blur surgery studies and injection studies together. If you'd like help reading a study or a trial listing, email hello@vivonyx.com or use our Ask page. We'll give you a straight answer, including "the research doesn't know yet" when that's the truth.
Related reading
Educational disclaimer: This article is for general educational purposes only and is not medical advice, diagnosis, or treatment. It does not describe or suggest the treatment, cure, or prevention of any disease or condition. Regulatory status can change; check the cited FDA pages for current information. Talk with a qualified, licensed healthcare professional before making any medical decision.
References
MedlinePlus (U.S. National Library of Medicine). Rotator cuff problems. https://medlineplus.gov/ency/article/000438.htm
Vieira Ferreira N, Andrade R, Pinto Freitas T, et al. The role of injections of mesenchymal stem cells as an augmentation tool in rotator cuff repair: a systematic review. JSES Rev Rep Tech. 2025;5(2):231-242. PMID: 40321851. https://pubmed.ncbi.nlm.nih.gov/40321851/
Hernigou P, Flouzat Lachaniette CH, Delambre J, et al. Biologic augmentation of rotator cuff repair with mesenchymal stem cells during arthroscopy improves healing and prevents further tears: a case-controlled study. Int Orthop. 2014;38(9):1811-1818. PMID: 24913770. https://pubmed.ncbi.nlm.nih.gov/24913770/
Cole BJ, Kaiser JT, Wagner KR, et al. Prospective randomized trial of biologic augmentation with bone marrow aspirate concentrate in patients undergoing arthroscopic rotator cuff repair. Am J Sports Med. 2023;51(5):1234-1242. PMID: 36811557. https://pubmed.ncbi.nlm.nih.gov/36811557/
Kim YS, Sung CH, Chung SH, et al. Does an injection of adipose-derived mesenchymal stem cells loaded in fibrin glue influence rotator cuff repair outcomes? A clinical and magnetic resonance imaging study. Am J Sports Med. 2017;45(9):2010-2018. PMID: 28448728. https://pubmed.ncbi.nlm.nih.gov/28448728/
Cofano E, Minici R, Spina G, et al. Combined arthroscopic rotator cuff repair with mesenchymal stem cell augmentation shows similar functional outcomes but a higher structural integrity rate compared with isolated repair: a meta-analysis of comparative studies. JSES Int. 2025;9(4):1191-1198. PMID: 40959003. https://pubmed.ncbi.nlm.nih.gov/40959003/
Carola N, Serotte JC, Jung D, et al. Bone marrow aspirate concentrate may improve healing and function in rotator cuff repair: a systematic review. Arthroscopy. 2025;41(8):3052-3062. PMID: 39581273. https://pubmed.ncbi.nlm.nih.gov/39581273/
Hurley ET, Crook BS, Danilkowicz RM, et al. Bone marrow stimulation for arthroscopic rotator cuff repair: a meta-analysis of randomized controlled trials. Am J Sports Med. 2024;52(12):3167-3172. PMID: 38328818. https://pubmed.ncbi.nlm.nih.gov/38328818/
Jo CH, Chai JW, Jeong EC, et al. Intratendinous injection of autologous adipose tissue-derived mesenchymal stem cells for the treatment of rotator cuff disease: a first-in-human trial. Stem Cells. 2018;36(9):1441-1450. PMID: 29790618. https://pubmed.ncbi.nlm.nih.gov/29790618/
Centeno CJ, Fausel Z, Dodson E, et al. Percutaneous bone marrow concentrate and platelet products versus exercise therapy for the treatment of rotator cuff tears: a randomized controlled, crossover trial with 2-year follow-up. BMC Musculoskelet Disord. 2024;25(1):392. PMID: 38762734. https://pubmed.ncbi.nlm.nih.gov/38762734/
Moraes VY, Lenza M, Tamaoki MJ, et al. Platelet-rich therapies for musculoskeletal soft tissue injuries. Cochrane Database Syst Rev. 2014;(4):CD010071. PMID: 24782334. https://pubmed.ncbi.nlm.nih.gov/24782334/
Ryan J, Imbergamo C, Sudah S, et al. Platelet-rich product supplementation in rotator cuff repair reduces retear rates and improves clinical outcomes: a meta-analysis of randomized controlled trials. Arthroscopy. 2021;37(8):2608-2624. PMID: 33744318. https://pubmed.ncbi.nlm.nih.gov/33744318/
U.S. Food and Drug Administration. Important Patient and Consumer Information About Regenerative Medicine Therapies. https://www.fda.gov/vaccines-blood-biologics/consumers-biologics/important-patient-and-consumer-information-about-regenerative-medicine-therapies
U.S. Food and Drug Administration. Consumer Alert on Regenerative Medicine Products Including Stem Cells and Exosomes. https://www.fda.gov/vaccines-blood-biologics/consumers-biologics/consumer-alert-regenerative-medicine-products-including-stem-cells-and-exosomes
ClinicalTrials.gov (U.S. National Library of Medicine). Search: rotator cuff, stem cell. https://clinicaltrials.gov/search?cond=Rotator%20Cuff&intr=stem%20cell
ClinicalTrials.gov. NCT06817616: Arthroscopic rotator cuff repair with umbilical cord-derived mesenchymal stem cells for large to massive rotator cuff tears. https://clinicaltrials.gov/study/NCT06817616