Knee treatments differ in relief, risk, and cost

Home care still matters when you compare treatments

Stronger leg muscles can support the knee and make daily movement easier. Weight loss may reduce strain when it applies, though it isn’t the whole answer.

A cold pack can be judged over several days, while exercise often needs several weeks. Ask how long to try medicine or physical therapy before changing course.

Pills can affect the stomach, kidneys, heart, or blood pressure. A doctor can match the safer choices to your health and current medicines.

Cortisone often brings relief measured in weeks

Cortisone calms soreness inside the joint, and relief is often measured in weeks. Some knees improve longer, but others don’t gain much relief.

A flare, meaning a short rise in soreness after the needle treatment, can follow. Flushing and higher blood sugar can also occur.

Ask whether the aim is easier walking, better sleep, or less trouble on stairs. If the last relief was brief, another round isn’t the only choice.

Gel injections for knee soreness may bring little change

Gel is placed inside the knee joint through a needle. Short-term soreness, swelling, bleeding, or infection can follow.

A large review found the average pain change was smaller than people were expected to notice. Other research found no clear pain benefit compared with salt water.

This means walking or stairs may feel no different after gel. Ask about the full cost and what comes next if the first course doesn’t help.

PRP uses material gathered from your own blood

Platelet-rich plasma, or PRP, is made by spinning blood drawn from you. The spinning gathers platelets, blood parts that carry natural growth factors, into a smaller amount.

Concentrated PRP means that this blood material contains more platelets. The amount of platelets and white blood cells can differ, which may change short-term soreness.

Studies disagree about how much PRP helps a sore knee. Ask which activities to avoid during the first days and which symptoms need a call.

Sources

1. A 2024 AJR review of corticosteroid injection side effects lists local effects (post-injection flare, skin hypopigmentation and atrophy, infection, tendon rupture, accelerated osteoarthritis progression, osseous injury) and systemic effects (adrenal suppression, facial flushing, hypertension, hyperglycaemia, osteoporosis), and calls for targeted pre-injection counselling for specific populations.

   Kamel SI, et al. — Local and Systemic Side Effects of Corticosteroid Injections for Musculoskeletal Indications.. AJR Am J Roentgenol, 2024. DOI: 10.2214/AJR.23.30458.

2. A study using fluoroscopy as the reference standard confirmed that injectate placed into the suprapatellar recess under ultrasound guidance disperses into the tibiofemoral joint after a brief bout of walking, and that blinded radiologist review corroborated the interventionalist's reading of correct needle placement.

   Varlotta C, et al. — Accuracy of ultrasound-guided knee injections confirmed by fluoroscopy.. Interv Pain Med, 2023. DOI: 10.1016/j.inpm.2022.100174.

3. A meta-analysis found ipsilateral intra-articular corticosteroid injection within 3 months BEFORE joint arthroplasty was associated with increased periprosthetic joint infection risk, and the authors recommend against performing arthroplasty on a joint injected within that window - while injections given at any time overall showed no such association.

   Lai Q, et al. — Prior Intra-articular Corticosteroid Injection Within 3 Months May Increase the Risk of Deep Infection in Subsequent Joint Arthroplasty: A Meta-analysis.. Clin Orthop Relat Res, 2022. DOI: 10.1097/CORR.0000000000002055.

4. FDA's HCT/P guidance sets out the minimal-manipulation and homologous-use criteria that decide whether a human cell or tissue product is regulated solely under 21 CFR Part 1271 (section 361) or requires a biologics licence; cell-based orthopaedic injections that fall outside those criteria are unapproved drugs and biological products, and no cell-based product is FDA-approved to treat osteoarthritis.

   U.S. Food and Drug Administration — Regulatory Considerations for Human Cells, Tissues, and Cellular and Tissue-Based Products: Minimal Manipulation and Homologous Use - Guidance for Industry and FDA Staff. U.S. Food and Drug Administration, 2020.

5. The RESTORE randomized trial (288 participants, leukocyte-poor PRP, 3 weekly injections) found no significant difference from saline placebo at 12 months in knee pain (-2.1 vs -1.8 points; difference -0.4, 95% CI -0.9 to 0.2) or in medial tibial cartilage volume (-1.4% vs -1.2%), with 29 of 31 secondary outcomes also showing no between-group difference.

   Bennell KL, 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.

6. A 2024 network meta-analysis of 48 studies (9,338 knees) at minimum 6-month follow-up ranked PRP first for pain and function (SUCRA 91.5), then BMAC (76.5) and hyaluronic acid (53.1), with corticosteroid (15.2) barely above placebo (13.7) at that time point.

   Jawanda H, et al. — Platelet-Rich Plasma, Bone Marrow Aspirate Concentrate, and Hyaluronic Acid Injections Outperform Corticosteroids in Pain and Function Scores at a Minimum of 6 Months as Intra-Articular Injections for Knee Osteoarthritis: A Systematic Review and Network Meta-analysis.. Arthroscopy, 2024. DOI: 10.1016/j.arthro.2024.01.037.

7. 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.