Stem Cell Therapy for Shoulder Injuries: How Regenerative Care Approaches Rotator Cuff and Tendon Damage

For most rotator cuff problems, nonsurgical care built around exercise comes first, and OrthoInfo reports it relieves pain and improves function in about 80 to 85% of patients. The stem cell evidence is thin: the one randomized trial cited here compared a bone marrow injection with home exercise in 51 people, without a placebo. Complete tears with weakness or a recent injury need a surgeon’s opinion.

What kind of shoulder problem do you have?

The right treatment depends on what is damaged, so start with the diagnosis.

Sources for the table: OrthoInfo; OrthoInfo.

What does the evidence show for stem cell injections?

The trial cited here randomized 51 people with tears of the supraspinatus, one of the four rotator cuff tendons, 34 to a bone marrow concentrate injection with platelet products and 17 to home exercise. At three months the injection group reported more improvement in arm function (a median change of 11.7 points against 3.8 on the DASH questionnaire, a 0 to 100 arm disability score on which lower is better) and in pain (BMC Musculoskeletal Disorders, 2024).

Read that result with its limits:

• No placebo. The comparison was an injection against home exercise, and patients knew which one they got, so the trial cannot separate the effect of the injection from the effect of expecting a procedure to help.
• A short comparison. After three months, people in the exercise group could switch to the injection, so the two groups were no longer kept apart.
• The MRI finding has no comparison. The report says 73% of treated patients with scans before and after “showed evidence of healing”; the exercise group’s scans were not compared.
• Financial ties. Several authors worked for, or held shares in, the company that sells this treatment (BMC Musculoskeletal Disorders, above).
• A small study. 51 people in one trial is not enough to settle the question.

The American College of Rheumatology guideline that recommends against stem cell injections covers arthritis of the hand, hip and knee, not the shoulder (ACR), so there is no guideline position to cite here either way. PRP in the shoulder and other tendons has its own evidence, covered in what PRP trials have and have not shown.

Why start with exercise?

OrthoInfo lists exercises that “restore movement and strengthen your shoulder” among the first treatments for a rotator cuff tear, and says nonsurgical care “avoids the major risks of surgery, such as infection, permanent stiffness, anesthesia complications” (OrthoInfo, above). It is also the step that tells you whether you need anything else. How exercise and injections fit together, and what each costs you, is on our page about whether to choose physical therapy or an injection first.

Questions before a shoulder injection

Whether you are someone who should not be treated with stem cells at all is covered on the page about who should not be treated with stem cells. If you are going ahead with a consultation, these are the points to settle:

• What exactly is torn? Ask to see the imaging report that says whether the tear is partial or full-thickness and how large it is.
• What will be injected, and from where? Bone marrow is drawn from the back of the hip bone, which has its own risks; those, and what the FDA allows clinics to do with the cells, are covered in the guide to how stem cell products are regulated.
• How will the needle be guided, and how is placement confirmed?
• What will recovery involve? Ask for a written plan with the reason behind each limit. The page on recovery and warning signs lists the signs of infection that need a call.
• What is the total cost, and what happens if it does not help? A second, more expensive procedure offered as the automatic next step is a warning sign.

Our step-by-step clinic evaluation covers the checks to do before a visit, and the signs of a clinic to avoid apply to shoulder care too.

When is surgery the better path?

OrthoInfo lists situations in which surgery may be recommended for a rotator cuff tear (OrthoInfo, above):

• pain that does not improve with nonsurgical methods
• symptoms that have lasted 6 to 12 months
• a large tear, over 3 cm, with good quality surrounding tissue
• significant weakness and loss of shoulder function
• a tear caused by a recent, acute injury

An injection is not a way around these. If you have a recent injury with sudden weakness, see a surgeon promptly rather than waiting to see whether an injection works.

The case for the injection, and its limit

The trial did find better short-term scores after the injection than after home exercise, and home exercise is a real alternative that patients use, so beating it is not meaningless. The MRI finding, if confirmed in a controlled comparison, would matter more than the scores. People who want to avoid surgery reasonably look for options like this. But the result comes from one small, unblinded study without a placebo, with several authors tied to the company that sells the treatment. That is a reason for further trials, not a reason to pay for the procedure as if the question were settled.

Stem cells for the shoulder, for now

Start with a clear diagnosis and a proper course of exercise-based care, which relieves pain in about 80 to 85% of patients in OrthoInfo’s figures. For now, a stem cell injection for the shoulder rests on one small, unblinded trial against home exercise. That makes it an option to weigh as an experiment, not a proven alternative, and a recent injury with sudden weakness still belongs with a surgeon first.

This page is general information, not medical advice.