PRP injection recovery time: the blood-based shot can feel sore for days

prp injection side effects often start with soreness

A treated joint often feels more sore, stiff or swollen for a few days. The ache may rise before it eases. Soreness and swelling at the shot site are common after PRP. They don't show that the treatment worked or failed. Give the joint an easier schedule while it is sore. A cold pack may help if the clinic says it is safe. Follow the written advice about medicine and movement. Another person's recovery time may not fit your joint.

The usual short flare starts settling instead of getting worse.

Long walks, repeated stairs and heavy bags can wait

Hard use means more than a workout. For a knee, it can include carrying groceries, climbing stairs many times or taking a long walk. Lifting a bag or reaching a high shelf can bother the shoulder. As the ache eases, add activity in small amounts. A flat walk is easier to control than a rocky trail. Keep doing exercises the clinic has approved, but stop if soreness turns sharp or keeps rising.

Comfortable movement counts more than a fast return to full effort.

Heat, spreading redness or fever needs a prompt call

Call the clinic when redness or warmth spreads instead of fading. Fever, leaking fluid or pain that keeps rising also needs attention. Swelling with calf pain must be checked that day. Those signs aren't the common soreness around the shot. Improvement can take time, so one easy morning proves little. One bad day also doesn't show whether the treatment will help. Note changes in sleep, walking, stairs and chores for the next visit.

Get prompt care if you feel ill or the pain becomes severe.

Sources

1. A systematic review and meta-analysis of adverse events in randomized trials of intra-articular PRP for knee osteoarthritis found PRP associated with mild, transient adverse events - knee pain and swelling - that typically resolve without intervention, and more frequent with LEUKOCYTE-RICH formulations. Leukocyte-poor PRP had a safety profile similar to hyaluronic acid. Knee stiffness was more frequent with PRP than with normal saline (P=.031). No severe adverse events were reported in any group.

   Nakagawa HF, Kim J, Rabinowitz J, et al. — Assessment of adverse events and safety associated with intra-articular platelet-rich plasma injections compared to other injectates for knee osteoarthritis: A systematic review and meta-analysis. PM&R, 2026. DOI: 10.1002/pmrj.70141.

2. A Bayesian network meta-analysis of nine studies (six RCTs, 1055 patients) found leukocyte-POOR PRP produced significantly better WOMAC scores than hyaluronic acid (mean difference -21.14; 95% CI -39.63 to -2.65) and than placebo (-17.84; 95% CI -34.95 to -0.73), while leukocyte-RICH PRP showed no such significant difference versus placebo. PRP of either type caused more local adverse reactions than hyaluronic acid (OR 5.63; 95% CI 1.38-22.90), almost always local swelling and pain, with no difference in safety between the two PRP types.

   Riboh JC, Saltzman BM, Yanke AB, et al. — Effect of Leukocyte Concentration on the Efficacy of Platelet-Rich Plasma in the Treatment of Knee Osteoarthritis. American Journal of Sports Medicine, 2016. DOI: 10.1177/0363546515580787.

3. The Cochrane review of STEM CELL injections for knee osteoarthritis concluded that on low-certainty evidence they may slightly improve pain and function, with uncertainty about effects on quality of life, treatment success and structural progression, and uncertainty about safety. This matters on a PRP site because 'stem cell therapy' is routinely used as a marketing label for PRP; they are different products with different evidence and PRP must never be described as a stem cell treatment.

   Whittle SL, Johnston RV, McDonald S, et al. — Stem cell injections for osteoarthritis of the knee. Cochrane Database of Systematic Reviews, 2025. DOI: 10.1002/14651858.CD013342.pub2.

4. A 12-centre randomized controlled trial of 230 patients with chronic lateral epicondylar tendinopathy compared tendon needling with leukocyte-enriched PRP against tendon needling alone. At 12 weeks there was no significant difference (55.1% versus 47.4% pain improvement; P=.163). At 24 weeks the PRP group reported 71.5% versus 56.1% pain improvement (P=.019), a 83.9% versus 68.3% success rate (P=.037), and significantly less residual elbow tenderness (29.1% versus 54.0%; P=.009). No significant complications occurred in either group.

   Mishra AK, Skrepnik NV, Edwards SG, et al. — Efficacy of platelet-rich plasma for chronic tennis elbow: a double-blind, prospective, multicenter, randomized controlled trial of 230 patients. American Journal of Sports Medicine, 2014. DOI: 10.1177/0363546513494359.

5. A meta-analysis of 73 articles covering 5,895 patients quantified the PLACEBO response to intra-articular injection in knee osteoarthritis: statistically and clinically significant improvements in pain, function and quality of life at 1, 3 and 6 months, with responder rates above 50% at each of those points, declining by 12 months. The placebo response was stronger in trials with more female participants and in more recently published trials. This is why an uncontrolled 'our patients improved' figure carries almost no information.

   Previtali D, Boffa A, Di Laura Frattura G, et al. — Placebo response to intra-articular injections in knee osteoarthritis: magnitude, evolution over time, and influencing factors. A systematic review and meta-analysis with meta-regression. EFORT Open Reviews, 2025. DOI: 10.1530/EOR-2025-0022.

6. A placebo-controlled, double-blind randomized trial of 40 patients with chronic rotator cuff tendinopathy compared a single ultrasound-guided subacromial injection of 5 mL PRP with 5 mL saline, with both groups completing a 6-week standard exercise programme and follow-up to one year. PRP did not produce better outcomes than saline on any measure - a reminder that the exercise programme, not the injectate, carried the improvement.

   Kesikburun S, Tan AK, Yilmaz B, et al. — Platelet-rich plasma injections in the treatment of chronic rotator cuff tendinopathy: a randomized controlled trial with 1-year follow-up. American Journal of Sports Medicine, 2013. DOI: 10.1177/0363546513496542.