If you have joint pain, tendinopathy, or a sports injury, your doctor has likely offered you a cortisone shot. They're quick, inexpensive, and they work — at least for a few weeks. But what actually happens inside the joint after that shot? And how does PRP compare when you look beyond the short-term relief? At Purety Family Medical Clinic in Santa Barbara, Dr. Jonathan Birch (NMD, RMSK) has performed over 4,000 regenerative injections. Here's an honest, evidence-based look at both options.
What Is a Cortisone Injection?
Cortisone (corticosteroid) injections deliver a synthetic version of cortisol directly into an inflamed joint, bursa, or tendon. They work by suppressing the local inflammatory response. The result is often dramatic: significant pain relief within days, sometimes hours.
For many patients, that relief is exactly what they need — to get through a busy week, compete in an event, or bridge to a more definitive treatment. Used once or twice, cortisone injections are a reasonable tool. The problem is what happens with repeated use, and what the evidence says about joint health over time.
What Does the Research Say About Cortisone?
A landmark 2017 study published in JAMA followed 140 patients with knee osteoarthritis over two years. Half received cortisone injections every 12 weeks; half received saline injections. The cortisone group had greater cartilage loss and no meaningful improvement in pain or function compared to saline — despite experiencing short-term relief. The anti-inflammatory effect was real. The structural damage was also real.
A 2021 meta-analysis in Radiology found that corticosteroid injections were associated with accelerated joint damage, stress fractures, and progression to joint replacement in a significant subset of patients. The authors concluded that "repeated corticosteroid injections should be used with caution" in patients with moderate-to-severe osteoarthritis.
For tendons, the data are similarly sobering. A Cochrane review of corticosteroid injections for tendinopathy found that while short-term pain reduction was consistent, patients were significantly more likely to have worse outcomes at 6–12 months compared to patients who received no injection at all — a phenomenon researchers call the "cortisone rebound."
None of this means cortisone injections are never appropriate. They remain useful for acute flares, inflammatory bursitis, and situations where short-term relief is the primary goal. But for patients with chronic joint degeneration or recurrent tendinopathy who want to preserve function long-term, the evidence suggests cortisone is not the right tool.
What Is PRP?
Platelet-Rich Plasma (PRP) is derived from your own blood. A sample is drawn, placed in a centrifuge to concentrate the platelet fraction, and then injected — under ultrasound guidance — directly into the injured tissue. Platelets contain dozens of growth factors, including PDGF, TGF-β, IGF-1, and VEGF, that orchestrate the tissue repair process.
Unlike cortisone, which suppresses inflammation, PRP works with your body's healing cascade. It signals damaged tissue to begin the repair process — recruiting stem cells, promoting collagen synthesis, and stimulating angiogenesis. The result is actual tissue regeneration rather than temporary symptom suppression.
What Does the Research Say About PRP?
The evidence base for PRP has grown substantially over the last decade. A 2021 systematic review and meta-analysis in the American Journal of Sports Medicine, analyzing 18 randomized controlled trials with 1,088 patients, found that PRP was significantly superior to hyaluronic acid and corticosteroid injections for knee osteoarthritis pain at both 6-month and 12-month follow-up.
A 2019 study in the British Journal of Sports Medicine reviewed PRP for lateral epicondylitis (tennis elbow). Patients receiving PRP had significantly better outcomes at 6 and 12 months compared to cortisone. Critically, the cortisone group had higher rates of symptom recurrence and worse long-term function — consistent with the "cortisone rebound" effect seen in tendinopathy research.
For rotator cuff, Achilles tendinopathy, and plantar fasciitis, multiple randomized trials have shown PRP to be at least equivalent to cortisone in the short term and significantly superior at 3, 6, and 12 months.
Why Ultrasound Guidance Matters
A critical variable that affects PRP outcomes — often omitted from popular discussions — is whether the injection is placed accurately. Studies show that without imaging guidance, injections into specific structures like the supraspinatus, the patellar tendon, or the AC joint miss their target a significant percentage of the time. A 2019 study in Arthroscopy found that unguided knee injections miss the intra-articular space in up to 30% of cases.
Dr. Birch is certified in musculoskeletal sonography (RMSK) and performs all PRP injections under real-time ultrasound guidance. This ensures accurate delivery — one of the most important factors in achieving good outcomes. It also allows him to visualize the pathology being treated, confirm needle placement, and document the procedure.
PRP vs. Cortisone: Who Should Choose Which?
This isn't a binary choice for every patient. Here's a practical framework:
- Cortisone may be appropriate if you need acute pain relief for a specific event, have inflammatory bursitis or acute tenosynovitis, or are preparing for a procedure and need a bridge to healing.
- PRP is typically preferred if you have mild-to-moderate osteoarthritis, chronic tendinopathy, a partial tendon or ligament tear, or a history of cortisone injections that have provided diminishing returns. PRP is also the stronger choice for younger patients who are trying to avoid joint replacement.
For patients with significant joint degeneration or who have had multiple prior cortisone injections, a combination approach — using PRP alongside prolotherapy or stem cell matrix injections — is sometimes the most appropriate plan.
What to Expect at Purety Clinic
If you're considering PRP, we begin with a thorough consultation and musculoskeletal ultrasound evaluation. Dr. Birch reviews your imaging, discusses the full range of regenerative options, and designs a treatment plan specific to your anatomy and goals. PRP injections are performed on-site under real-time ultrasound guidance.
Most patients begin to notice improvement within 4–8 weeks, with continued gains over 3–6 months as tissue remodeling occurs. Many require 1–3 sessions depending on the condition and severity.
To schedule a consultation or learn more about PRP injections at Purety Clinic, call (805) 500-8300 or submit a request online. We also work with patients who have orthopedic injuries including partial tendon tears, ligament sprains, and early osteoarthritis.
