Knee Injections in Boca Raton: Cortisone vs. Hyaluronic Acid vs. PRP vs. Stem Cells

The following scenario is hypothetical and does not describe a real patient.

Picture a 67-year-old retiree in Boca Raton who plays pickleball four mornings a week and walks the beach on weekends. Over the past year, her right knee has started to ache after games, feels stiff when she gets out of the car, and swells a little by evening. An X-ray shows knee osteoarthritis. A friend at the courts swears by “gel shots,” and another swears by platelet-rich plasma (PRP). Her neighbor in Delray Beach just gets a cortisone shot every few months, and someone at her club has asked about stem cell injections.

Which one, if any, is right for her?

At AnswersMD in Boca Raton, Dr. Divino D’Alessio Jr., MD, DABFM, CAQSM, answers that question the same way for every patient: diagnosis first, then the right injection for that knee, personalized to the patient’s goals. This guide explains what cortisone, gel shots, PRP and stem cell injections are, what the research and the U.S. Food and Drug Administration (FDA) say about each one, and how injections fit into a bigger plan for staying active with knee arthritis.

Key facts at a glance

• About 33 million U.S. adults have osteoarthritis, the most common type of arthritis ¹.
• 24.3% of Palm Beach County residents were 65 or older in the 2020 Census, compared with 21.2% statewide ². Osteoarthritis becomes more likely with age ¹.
• Cortisone (corticosteroid): strongly recommended for knee osteoarthritis by the American College of Rheumatology (ACR). Relief in trials lasted up to about 3 months ³⁴.
• Hyaluronic acid (“gel”): the evidence is mixed ³⁴.
• PRP: offered at AnswersMD in Boca Raton. Expert groups differ on PRP, and the research is still growing. The American Academy of Orthopaedic Surgeons (AAOS) says PRP may reduce pain and improve function ⁴. Devices used to prepare PRP are FDA-cleared, but PRP itself is not FDA-approved as a knee osteoarthritis treatment ⁹¹⁰.
• Stem cell injections: offered at AnswersMD for joint pain by Dr. D’Alessio. Research is still early, and stem cell products are not FDA-approved for knee osteoarthritis ¹¹¹³.
• Every injection at AnswersMD, whatever it is, is given under ultrasound guidance.

How does Dr. D’Alessio approach knee pain at AnswersMD?

Dr. D’Alessio is a primary care doctor for the whole family as well as a sports medicine expert, board certified in family medicine and sports medicine. He practices at AnswersMD’s Royal Palm office in Boca Raton. His approach is personalized to you and your goals.

• Diagnosis first. Every treatment starts with an exam to find what’s actually causing the pain. Dr. D’Alessio decides case by case whether to use in-office diagnostic ultrasound, and he uses it often. When more imaging is needed, he orders X-rays or an MRI.
• The right injection for that knee. If an injection makes sense, he recommends one after your evaluation, based on your diagnosis, your health history and your goals. Options include cortisone, PRP and stem cell injections. Gel shots are decided case by case, but Dr. D’Alessio generally favors cortisone, PRP or stem cell options over gel shots, depending on the patient.
• Built around your goals, whether that’s finishing the pickleball season or walking the beach without thinking about your knee.
• More than a shot. Physical therapy, with exercise and strengthening guided by a physical therapist, is a key part of the plan, alongside any injection.
• Straight answers. PRP and stem cell injections aren’t right for every patient. If you’re not a good candidate, he’ll tell you directly.
• Shared decisions. He walks through the options with you and you decide together. If you want a standard, guideline-based plan, that’s what you get, and if you want to explore options beyond the guidelines, he’ll talk them through with you.
• Precise injections. Every injection at AnswersMD, whatever it is, is given under ultrasound guidance. PRP is prepared on site.

For AnswersMD members, sports medicine visits with Dr. D’Alessio are included with membership.

What’s causing your knee pain?

Not all knee pain is arthritis. Knee pain can come from tendinitis, bursitis, a meniscus (cartilage) tear, a ligament injury, kneecap problems, gout or, rarely, infection ⁵. The right treatment depends on the cause, which is why an exam, and often an X-ray, comes before any injection ⁵. At AnswersMD, that may also include an in-office ultrasound or an MRI.

Osteoarthritis (OA) is a disease that breaks down the joint over time. It causes pain, stiffness and swelling, and it can make work or daily activities harder ¹. Risk factors include older age, prior joint injury or overuse, extra body weight, family history, and female sex, especially after age 50 ¹. There’s no cure, but OA can be managed effectively ¹.

See a clinician promptly if you can’t bear weight on the knee, have severe pain even at rest, the knee buckles or locks, the knee looks deformed, you have fever with redness, warmth or a lot of swelling, or you have calf pain or swelling below the sore knee ⁵.

What else helps knee arthritis besides injections?

The strongest evidence supports the basics, and a good injection plan is built on them.

Physical therapy is a key part of the plan. Exercise is one of the most strongly recommended treatments for knee osteoarthritis. Both the ACR and the AAOS give it their strongest rating ³⁴, and the AAOS guideline summary calls exercise and physical therapy “excellent modalities” for pain and function in knee OA ¹⁴. A physical therapist builds an exercise program around your knee, strengthening the muscles that support it, improving balance and movement, and progressing at a safe pace. Physical therapy works alongside injections, not instead of them.

The ACR also strongly recommends ³:

• Exercise, such as walking, strengthening, neuromuscular training or aquatic exercise. Supervised programs tend to work better.
• Weight loss for people with knee OA who are overweight. A loss of 5% or more of body weight can make a difference, and benefits grow with more loss.
• Tai chi, self-management programs, and a cane or knee brace when needed.
• Topical NSAIDs (anti-inflammatory gels) for the knee, and oral NSAIDs when appropriate. The ACR notes that topical NSAIDs should be considered before oral ones.

The ACR also says management should begin with treatments that have the least whole-body exposure or toxicity ³. Injections work best alongside these foundations, especially physical therapy and exercise, not instead of them.

How well do cortisone shots work for knee arthritis?

What it is: A corticosteroid, usually mixed with a local anesthetic, injected into the joint to calm pain and inflammation ⁶.

What the evidence says:

• The ACR strongly recommends intra-articular glucocorticoid (steroid) injections for knee OA, based on trials showing short-term benefit ³. It also conditionally recommends steroid injections over other injection types, noting that the evidence for steroids is “of considerably higher quality” than for other agents ³.
• The AAOS says corticosteroid injections “could provide short-term relief,” with moderate-strength evidence. In its review, pain and function improved, but the effect “lasted only up to 3 months” ⁴.
• The AAOS also found that extended-release steroid injections can be used over immediate-release versions to improve outcomes (moderate strength) ⁴.

The cartilage question: In a two-year randomized trial published in JAMA, 140 patients with knee OA received triamcinolone (a steroid) or saline every 12 weeks. The steroid group had slightly more cartilage loss on MRI, a difference of about 0.11 mm, and no better pain relief than saline over two years ⁷. The ACR panel noted this finding but was uncertain of its clinical significance, because the cartilage change wasn’t linked to worse pain or function ³. The AAOS downgraded its steroid recommendation one level because of the potential risk of accelerating OA ⁴.

Possible side effects include a short-term flare of pain and swelling for up to two days, temporary facial flushing, and a temporary rise in blood sugar, which matters for people with diabetes. Less common risks include infection, skin thinning and, with repeated use, possible cartilage damage. That’s why clinicians typically limit how many shots a joint receives ⁶.

Bottom line: Of the options here, cortisone has the strongest guideline support for short-term relief ³⁴. Repeated long-term use raises cartilage questions that are still being studied ³⁷.

Is your knee keeping you off the court? We invite you to a complimentary meet & greet and office tour at our Royal Palm office in Boca Raton, where Dr. D’Alessio practices. Book at answersmd.com or call 561-933-3333.

Do gel shots (hyaluronic acid) work for knee arthritis?

What it is: Hyaluronic acid (HA) is a natural component of joint fluid. HA injections, often called “gel shots,” are meant to supplement the joint’s lubrication.

What the evidence says:

• The ACR conditionally recommends against HA injections for knee OA ³. Its review found that apparent benefits were limited to studies at higher risk of bias. When the analysis was restricted to low-risk-of-bias trials, the effect compared with saline “approaches zero” ³.
• The ACR adds an important nuance. For a patient who hasn’t responded adequately to exercise, NSAIDs and steroid injections, HA “may be viewed more favorably than offering no intervention,” as part of shared decision-making that acknowledges limited evidence ³.
• The AAOS says HA is not recommended for routine use (moderate strength). It found that some studies showed statistically significant benefits, but they often fell short of a clinically meaningful difference. The number needed to treat to see a tangible benefit was 17 patients, and the benefit was most evident at 6 weeks and 3 months ⁴.
• In the AAOS review, high- vs. low-molecular-weight and cross-linked vs. non-cross-linked HA products performed similarly ⁴.

Bottom line: Gel shots aren’t a first choice for most knees, but the ACR leaves room for them when other options haven’t given enough relief ³. At AnswersMD, they’re decided case by case. Dr. D’Alessio generally favors cortisone, PRP or stem cell options over gel shots, depending on the patient.

Is PRP an option for knee arthritis?

What it is: PRP is made from your own blood. A sample is drawn and spun in a centrifuge to concentrate the platelets, which contain growth factors, and then the concentrate is injected into the joint ⁸.

FDA status: According to the American Association of Hip and Knee Surgeons (AAHKS), many PRP preparation systems were brought to market through FDA’s 510(k) clearance pathway ⁹. One FDA-published 510(k) summary for a PRP preparation device, for example, lists its indication as mixing PRP with bone graft material during orthopedic surgery and states that “the PRP prepared by this device has not been evaluated for any clinical indications” ¹⁰. According to the AAHKS 2025 position statement, PRP injections into a hip or knee joint are therefore considered “off-label” ⁹. PRP is not FDA-approved as a treatment for knee osteoarthritis.

Where expert groups stand: Expert groups differ on PRP, and the research is still growing. The AAOS, in its 2021 guideline, states that PRP “may reduce pain and improve function” in knee OA, based on limited evidence, with mixed results and differences between early- and late-stage arthritis ⁴. In studies comparing PRP with HA, results diverged after six months, and a meta-analysis at 9 to 12 months favored PRP ⁴. The AAOS also flagged a safety question from one study that needs further evaluation ⁴. Other groups have been more cautious: the ACR’s 2019 guideline, based on research through 2018, does not recommend PRP, citing how much PRP preparations vary from one system to another ³, and a 2025 AAHKS statement on advanced arthritis doesn’t recommend biologic treatments, including PRP, for routine use in advanced disease ⁹.

How Dr. D’Alessio decides when PRP fits: He looks at what’s causing your pain, how advanced the arthritis is, your health history, what you’ve already tried and your goals. If PRP fits, he explains what to expect, including the risks. If it doesn’t, he’ll tell you directly and walk you through the other options.

Possible side effects: The most common is temporary pain at the injection site. AAOS patient information notes that other problems, such as infection, tissue damage or nerve injury, appear to be no more common than with cortisone injections ⁸.

Summary: PRP is an option at AnswersMD for the right knee. Expert groups differ, the research is still growing, and PRP is not FDA-approved for knee OA ³⁴⁹¹⁰. Results vary from person to person and aren’t guaranteed, so whether PRP fits your knee depends on your diagnosis, the stage of your arthritis and your goals.

Are stem cell injections an option for knee arthritis?

What it is: At AnswersMD, Dr. Divino D’Alessio Jr., MD, DABFM, CAQSM, offers stem cell injections for joint pain from arthritis and orthopedic injuries. The product comes from donated umbilical cord tissue and, according to its supplier, contains mesenchymal stem cells. Like every injection at AnswersMD, it’s given under ultrasound guidance.

FDA status: Stem cell products are not FDA-approved for osteoarthritis or other orthopedic conditions ¹¹. In 2025, Florida updated its law to allow physicians to use certain stem cell therapies that are not FDA-approved for orthopedics, wound care or pain management, under specific requirements for how the cells are sourced and stored and for patient consent ¹². The Florida notice at the top of this page applies.

What the research shows: This is an area of active research. A 2025 Cochrane review of 25 trials found, based on low-certainty evidence, that stem cell injections may slightly improve pain and function compared with placebo, and the reviewers noted that open questions remain, including their effects on the joint over time ¹³. These trials looked at a range of different cell products and methods, so their results don’t predict how any one patient will respond to a specific treatment. Individual results vary, and no outcome is promised or guaranteed. Major guidelines don’t yet include stem cell injections in routine care for knee OA, and research continues ³⁹.

How Dr. D’Alessio decides: As with PRP, he looks at what’s causing your pain, how advanced the arthritis is, your health history, what you’ve already tried and your goals, and he’ll tell you directly whether stem cells make sense for you. A stem cell injection isn’t a cure, and it isn’t guaranteed to regenerate cartilage, reverse arthritis or prevent surgery. Any improvement may be partial or temporary, or may not happen. Individual results vary. No outcome is promised or guaranteed.

Possible risks: pain, swelling or a flare after the injection; infection, including joint infection; allergic or immune reactions; bleeding or injury to nearby tissue; a small remaining risk of disease transmission from donor material despite screening and testing; rare, unpredictable effects such as abnormal tissue growth; and long-term effects that aren’t yet known ¹¹¹³.

How do cortisone, gel shots, PRP and stem cells compare?

	Cortisone	Hyaluronic acid	PRP	Stem cells
Where expert groups stand	Recommended for short-term relief 34	Evidence mixed; not for routine use 34	Groups differ; research still growing 349	Research still early; not yet part of routine guideline care 3913
At AnswersMD	Offered, ultrasound-guided	Case by case	Offered, prepared on site, ultrasound-guided	Offered for joint pain, ultrasound-guided
Findings in reviews	Relief up to about 3 months 4	Benefit most evident at 6 weeks to 3 months 4	Mixed. Some studies favor PRP at 9–12 months vs. HA 4	Low-certainty evidence from 25 trials; long-term effects unknown 13
Regulatory status and cautions noted by sources	Temporary blood-sugar rise and post-shot flare; repeated use and cartilage 67	Small average benefit 34	Preparation devices FDA-cleared; PRP not FDA-approved for knee OA; preparations vary 3910	Not FDA-approved for osteoarthritis; Florida notice required; donor-material and immune risks 11

What should you ask before a knee injection?

1. What’s causing my pain? Is it arthritis, a meniscus or tendon problem, or something else?
2. Have we tried the foundations, such as exercise or physical therapy, weight management and topical anti-inflammatories?
3. Which injection do you recommend, and why, given my arthritis severity and health conditions such as diabetes?
4. How long might relief last, and how many injections are reasonable per year?
5. Will the injection be ultrasound-guided? At AnswersMD, every injection is. The ACR notes that imaging guidance may help ensure accuracy ³.
6. How does this plan fit my goals, whether that’s a sport, travel or simply walking without pain?
7. What’s the long-term plan if the injection doesn’t help?

How do I see Dr. D’Alessio for knee pain in Boca Raton?

Dr. Divino D’Alessio Jr., MD, DABFM, CAQSM, practices at AnswersMD’s Royal Palm office at 1801 S. Federal Highway in Boca Raton, close to Delray Beach, Highland Beach and Deerfield Beach. AnswersMD is a membership primary care practice, and sports medicine visits with Dr. D’Alessio are included with membership, with time for your questions for as long as you need.

The best first step is a complimentary meet & greet and office tour. Book at answersmd.com or call 561-933-3333.