Tendon injection · St. Louis

Tendon Injections: Precision Where the Rope Frayed

A tendon injection places your own platelet-rich plasma or other orthobiologic directly into and around a damaged tendon under live ultrasound. We use it for the rotator cuff, tennis and golfer’s elbow, gluteal tendons at the outer hip, the Achilles, the patellar tendon and the plantar fascia when rest, therapy and cortisone have not fixed the pain.

A chronic tendon is a rope that has started to fray. The fibers lose their tight parallel lines, the tissue fills with disorganized scar, and new blood vessels and nerves grow into places they do not belong. That is why it hurts every time you load it. Most chronic tendon pain is a failed repair. The tissue tried to heal, stalled, and stayed stalled.

Tendons have a poor blood supply to begin with. Repair workers arrive slowly and leave early. A tendon injection delivers them straight to the frayed section, and that only works if the needle is in the frayed section.

Which tendons can be treated with an orthobiologic injection?

Why does precision matter in a tendon injection?

A tendon problem is often a few millimeters wide. The damaged section of a gluteal tendon, a supraspinatus tear or a tennis-elbow origin can sit right next to healthy fibers and a fluid-filled bursa. Inject the bursa and you have treated the wrong structure. Inject a healthy section and you have wasted the product.

Under ultrasound we see the dark, swollen, disorganized area of the tendon, any partial tear, and the abnormal blood vessels growing into it. We guide the needle into that zone and spread the injection through it in several small passes. Each pass also breaks up the stalled scar and restarts the healing signal. Blind injection cannot do that. Read why on blind needle accuracy.

Does PRP work better than cortisone for tendons?

Cortisone feels better first. PRP lasts longer. That pattern repeats across tendons:

The reason is mechanical. Cortisone weakens collagen. A tendon that already lost its structure does not need a drug that loosens what is left. A 2025 meta-analysis of 27 trials across rotator cuff, elbow, plantar fascia and tenosynovitis reached the same conclusion: PRP’s mid-term results beat cortisone’s.

Why do some tendons keep failing?

Because tendons are metabolic tissue. Three drivers keep a tendon from healing:

That is why lifestyle and behavior are 40 to 50% of our protocol, with laser therapy, rehabilitation and metabolic optimization built around the injection.

What does rehab look like after a tendon injection?

The injection restarts healing. Rehab teaches the new fibers which direction to line up. Protect the area for the first few days and follow the rehab plan. After that, the plan moves to slow, controlled loading of the tendon, the same principle shown in the rotator cuff exercise evidence. A tendon that is never loaded heals weak. A tendon that is overloaded tears again.

You can’t make a carrot grow faster than it grows. Collagen remodels over months. Some feel better in three weeks; others need a second or third treatment, decided by how the tissue responds.

What happens on the day of the injection?

We draw your blood and process it in an FDA-cleared preparation system. The skin is numbed with local anesthetic. You stay awake, you watch the ultrasound screen if you want, and most patients drive themselves home. Expect soreness for about 48 hours after PRP. For tendons that have failed injections, TenJet debridement is another option.

Frequently asked questions

Is a tendon injection the same as a bursa injection?

No. A bursa is a fluid sac next to the tendon. Under ultrasound we treat the damaged tendon itself and only treat the bursa if it is part of the problem.

Can PRP help a partial rotator cuff tear?

Yes, for many partial-thickness tears. Pooled trials show PRP improves shoulder function more than cortisone and with fewer side effects. Full-thickness tears with retraction are a surgical conversation.

How soon can I use the arm or leg after a tendon injection?

Protect the area for the first few days and follow the rehab plan, which then builds load in steps.

Will I need more than one tendon injection?

Some feel better in three weeks; others need a second or third treatment, decided by how the tissue responds.

Why not just get another cortisone shot?

Cortisone relieves pain faster in the first weeks but weakens collagen. For tendons, PRP produces better results at six months and beyond.

Is a tendon injection covered by insurance?

Orthobiologics are not billed to insurance. HSA and FSA funds are generally eligible.

Sources

  1. Yuwarungsikul C, et al. Platelet-rich plasma provides modest but durable functional benefit over corticosteroid for rotator cuff tendinopathy: A systematic review and meta-analysis of randomized controlled trials. Knee Surg Sports Traumatol Arthrosc, 2026. PMID 42021740
  2. Xu Y, et al. Platelet-Rich Plasma Has Better Results for Long-term Functional Improvement and Pain Relief for Lateral Epicondylitis: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Am J Sports Med, 2024. PMID 38357713
  3. Kuhns BD, et al. Improved Outcomes With Platelet-Rich Plasma for Treating Extra-articular Hip Pathology Especially Greater Trochanteric Pain Syndrome and Hamstring Injury: A Systematic Review of Randomized Controlled Trials. Arthroscopy, 2026. PMID 41838530
  4. Rayo-Martín R, et al. Comparison of PRP Injections Versus Corticosteroid Injections in Plantar Fasciitis: Systematic Review and Meta-analysis. Foot Ankle Spec, 2025. PMID 40913486
  5. Ye Z, et al. Platelet-rich plasma and corticosteroid injection for tendinopathy: a systematic review and meta-analysis. BMC Musculoskelet Disord, 2025. PMID 40200209

Speak to someone

If a shoulder, elbow, hip, heel or Achilles has outlasted rest, therapy and cortisone, a precise ultrasound-guided tendon injection is the bridge between failed conservative care and surgery. We see patients at our office at 4477 Woodson Rd in St. Louis. Over 90% of our accepted case-study patients see significant improvement. Request our orthobiologics guide or call (314) 481-5000 to find out whether your tendon is a candidate.

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