Good knee care explains the likely relief and the limits

Short relief isn't proof that the knee was repaired

A steroid may bring brief relief when soreness blocks sleep or makes movement hard. Repeated procedures can raise the chance of harm to the knee. Ask whether the treatment is meant for one visit or repeated care.

A lower pain score and a longer walk are changes you can feel. A change seen only on a scan may not improve your day. Ask what people could actually do after treatment. If the answer only tells how the procedure might work, it doesn't tell you whether people felt better.

PRP can differ from one clinic to another

PRP means platelet-rich plasma. Blood from your arm is spun to gather more platelets, the small blood parts involved in healing. The prepared blood is then placed in the knee. One large study kept people from knowing whether they got PRP or salt water; PRP didn't give clearer relief, though other research found people moved better in daily life.

In concentrated PRP, the prepared blood contains a larger share of those small blood parts. That may help explain why results vary, but the higher amount doesn't promise more relief. Ask which kind the clinic uses and why. Get the visit count, likely result, and full price in writing. Then ask whether your insurance pays any part.

Safety and follow-up need clear answers before treatment

Tell the clinician about every medicine you take, especially medicine that thins blood. Mention any past bleeding trouble. Ask who will do the procedure and how the knee may feel later. Mild soreness and swelling can happen, but the clinic needs to name signs that aren't normal.

Don't wait on severe or rising pain, spreading redness, drainage, fever, or feeling ill. Those signs need urgent medical care. Before leaving, get the after-hours phone number and return date. If the answers feel rushed, you can stop and speak with another clinician.

Sources

1. The RESTORE trial randomized 288 adults aged 50+ with symptomatic mild-to-moderate medial knee OA to three weekly leukocyte-poor PRP injections or saline placebo. At 12 months, pain change was -2.1 vs -1.8 points (difference -0.4; 95% CI -0.9 to 0.2; P=.17) and medial tibial cartilage volume change was -1.4% vs -1.2% (P=.81). 29 of 31 prespecified secondary outcomes showed no significant between-group difference. The authors concluded the findings 'do not support use of PRP for the management of knee OA.'

   Bennell KL, Paterson KL, Metcalf BR, et al. — Effect of Intra-articular Platelet-Rich Plasma vs Placebo Injection on Pain and Medial Tibial Cartilage Volume in Patients With Knee Osteoarthritis: The RESTORE Randomized Clinical Trial.. JAMA, 2021. DOI: 10.1001/jama.2021.19415.

2. A 2026 network meta-analysis of 21 RCTs (2,254 patients) found both leukocyte-poor and leukocyte-rich PRP significantly improved 6-12 month WOMAC function versus placebo (MD -10.54 and -13.20 respectively) and both were superior to hyaluronic acid, with leukocyte-poor PRP ranked first (P-score 0.96) — a materially more favourable read of PRP than the RESTORE trial, which is why this corpus presents both.

   Journal of Orthopaedic Surgery and Research authors — Leukocyte-rich versus leukocyte-poor platelet-rich plasma and hyaluronic acid for knee osteoarthritis: a systematic review and network meta-analysis.. Journal of Orthopaedic Surgery and Research, 2026. DOI: 10.1186/s13018-026-06689-4.

3. A 150-patient randomized trial reported that an absolute count of 10 billion platelets was needed for a PRP formulation to sustain benefit to one year versus hyaluronic acid (WOMAC and IKDC differences p<0.001; +120 m vs +4 m in 6-minute pain-free walking distance). Because clinic PRP systems vary widely in platelet yield, 'PRP' is not one intervention and results are not transferable between preparations.

   Bansal H, Leon J, Pont JL, et al. — Platelet-rich plasma (PRP) in osteoarthritis (OA) knee: Correct dose critical for long term clinical efficacy.. Scientific Reports, 2021. DOI: 10.1038/s41598-021-83025-2.

4. A JBJS systematic review screened 420 papers on intra-articular cellular therapy for knee OA and cartilage defects and found only SIX studies at Level III evidence or higher (4 Level II, 2 Level III), covering 300 knees, with wide variation in cell source, cell characterisation, adjuvant therapy and outcome assessment — meaning no consensus exists on indications, cell sources, preparation or delivery.

   Chahla J, Piuzzi NS, Mitchell JJ, et al. — Intra-Articular Cellular Therapy for Osteoarthritis and Focal Cartilage Defects of the Knee: A Systematic Review of the Literature and Study Quality Analysis.. Journal of Bone and Joint Surgery (American), 2016. DOI: 10.2106/JBJS.15.01495.

5. FDA states verbatim: 'None of these products have been approved for the treatment of any orthopedic condition, such as osteoarthritis, tendonitis, disc disease, tennis elbow, back pain, hip pain, knee pain, neck pain, or shoulder pain.' The only FDA-approved stem cell products in the United States are blood-forming (hematopoietic progenitor) cells derived from umbilical cord blood, approved only for disorders of blood production. There are currently NO FDA-approved exosome products.

   U.S. Food and Drug Administration — Consumer Alert on Regenerative Medicine Products Including Stem Cells and Exosomes. FDA (Center for Biologics Evaluation and Research), 2020.

6. A safety review of intra-articular PRP in knee OA found significantly higher rates of mild knee pain and swelling than hyaluronic acid (p<0.001), driven specifically by leukocyte-RICH formulations; leukocyte-poor PRP showed a safety profile similar to HA. No severe adverse events were reported in any group.

   PM&R authors — Assessment of adverse events and safety associated with intra-articular platelet-rich plasma injections compared with hyaluronic acid and saline in knee osteoarthritis.. PM&R, 2026. DOI: 10.1002/pmrj.70141.

7. In a 2-year, double-blind RCT of 140 patients with symptomatic knee OA and ultrasound synovitis, intra-articular triamcinolone 40 mg every 12 weeks caused significantly GREATER cartilage volume loss than saline (index-compartment cartilage thickness change -0.21 mm vs -0.10 mm; between-group difference -0.11 mm, 95% CI -0.20 to -0.03) with NO significant difference in pain (-1.2 vs -1.9 on the WOMAC Likert pain subscale).

   McAlindon TE, LaValley MP, Harvey WF, et al. — Effect of Intra-articular Triamcinolone vs Saline on Knee Cartilage Volume and Pain in Patients With Knee Osteoarthritis: A Randomized Clinical Trial.. JAMA, 2017. DOI: 10.1001/jama.2017.5283.