Knee findings cannot promise equal relief in the hip

Platelet-rich plasma (PRP) is a blood-based shot, and knee results do not prove hip relief

The knee sits close to the skin. The hip lies deeper, so a clinician may use image guidance, watching the needle on ultrasound or live X-ray, during a shot. That helps the clinician place it inside your hip joint.

The joints also carry weight in different ways. Several knee reports found less soreness after platelet-rich plasma (PRP), made by drawing the patient's blood and spinning it into layers. The platelet-rich layer is then used for the shot. Hip studies haven't shown an equal edge.

A scan can show wear in a person whose hip doesn't hurt. That isn't doubt about whether the scan found wear. It means the exam must show whether the wear matches your sore motion. Otherwise, care may focus on a finding that causes no trouble.

A salt-water comparison shows whether the tested shot caused relief

Much of the hip research compared PRP with a gel shot called hyaluronic acid. That gel is similar to a slippery substance in normal joint fluid. In hip research, the gel shot hadn't clearly beaten saline, a comparison made with sterile salt water.

If PRP only matches the gel shot, the study can't show that PRP caused relief. A salt-water group gives a fairer check because it doesn't contain either treatment.

After an exam, QC Kinetix offers PRP as a biologic therapy, meaning blood-based care prepared from the patient.

Ask whether a quoted result came from hips or knees. Then ask whether PRP was compared with gel or salt water. Your choice also depends on the exam, cost, and a clear aim for walking.

Sources

1. The evidence overview underpinning the 2020 EULAR recommendations on intra-articular therapies pooled 29 quality-appraised systematic reviews. Hyaluronic acid showed a small effect on pain and function in KNEE OA but not in hip OA or shoulder capsulitis; intra-articular glucocorticoid showed small effects in knee OA and on function in hip OA and shoulder capsulitis; PRP showed benefit in knee OA but NOT in hip OA, and mesenchymal stem cells behaved similarly. Overall conclusion: most intra-articular therapies exert SMALL effects and are well tolerated.

   Rodriguez-García SC, et al. — Efficacy and safety of intra-articular therapies in rheumatic and musculoskeletal diseases: an overview of systematic reviews.. RMD open, 2021. DOI: 10.1136/rmdopen-2021-001658.

2. A Bayesian network meta-analysis of 11 randomized trials (1353 patients) in hip osteoarthritis found that at 2-4 months and 6 months NO injectable - corticosteroid, hyaluronic acid or platelet-rich plasma - significantly outperformed a saline placebo injection for pain or function. Pooled change from baseline exceeded the minimal clinically important difference in every arm including placebo.

   Gazendam A, et al. — Intra-articular saline injection is as effective as corticosteroids, platelet-rich plasma and hyaluronic acid for hip osteoarthritis pain: a systematic review and network meta-analysis of randomised controlled trials.. British Journal of Sports Medicine, 2021. DOI: 10.1136/bjsports-2020-102179.

3. In a multicentre, randomized, placebo-controlled trial (n=85) of a single fluoroscopically-guided intra-articular hyaluronic acid injection for hip OA, the decrease in pain at 3 months did not differ from placebo (7.8 mm vs 9.1 mm on a 100 mm VAS; P=0.98), and responder rates were 33.3% versus 32.6%.

   Richette P, et al. — Effect of hyaluronic acid in symptomatic hip osteoarthritis: a multicenter, randomized, placebo-controlled trial.. Arthritis & Rheumatism, 2009. DOI: 10.1002/art.24301.

4. A systematic review and meta-analysis of six Level I/II randomized trials (211 PRP and 197 hyaluronic acid patients, mean follow-up ~12 months) found NO significant difference between PRP and hyaluronic acid in WOMAC, VAS or Harris Hip Score improvement for hip osteoarthritis, including in the leukocyte-poor PRP subanalysis.

   Belk JW, et al. — Platelet-Rich Plasma Versus Hyaluronic Acid for Hip Osteoarthritis Yields Similarly Beneficial Short-Term Clinical Outcomes: A Systematic Review and Meta-analysis of Level I and II Randomized Controlled Trials.. Arthroscopy, 2022. DOI: 10.1016/j.arthro.2021.11.005.

5. The AAOS evidence-based clinical practice guideline on Management of Osteoarthritis of the Hip states verbatim: STRONG evidence supports intra-articular corticosteroids to improve function and reduce pain in the SHORT TERM; STRONG evidence does NOT support intra-articular hyaluronic acid, because it does not perform better than placebo for function, stiffness and pain; STRONG evidence supports physical therapy for mild to moderate symptoms; STRONG evidence supports NSAIDs for short-term pain and function; and MODERATE evidence does not support glucosamine sulfate.

   American Academy of Orthopaedic Surgeons — Management of Osteoarthritis of the Hip: Evidence-Based Clinical Practice Guideline.. AAOS, 2017.

6. The PRIMA trial randomized 100 patients with ankle osteoarthritis to two ultrasound-guided intra-articular PRP injections or saline placebo. AOFAS scores improved 10 points with PRP (63 to 73) and 11 points with placebo (64 to 75); the adjusted between-group difference over 26 weeks was -1 (95% CI -6 to 3, p=0.56). The authors state the results do not support using PRP for ankle osteoarthritis. The evidence for a biologic in one joint does not transfer to another.

   Paget LDA, et al. — Effect of Platelet-Rich Plasma Injections vs Placebo on Ankle Symptoms and Function in Patients With Ankle Osteoarthritis: A Randomized Clinical Trial.. JAMA, 2021. DOI: 10.1001/jama.2021.16602.

7. A randomized controlled study of 111 patients aged 18-65 with hip osteoarthritis compared three weekly ultrasound-guided injections of PRP, hyaluronic acid, or both. PRP had the lowest VAS at every follow-up and beat HA significantly at 6 months (mean VAS 21 vs 44). But the WOMAC advantage present at 2 and 6 months was NO LONGER significant at 12 months, and the combination arm did worse than PRP alone.

   Dallari D, et al. — Ultrasound-Guided Injection of Platelet-Rich Plasma and Hyaluronic Acid, Separately and in Combination, for Hip Osteoarthritis: A Randomized Controlled Study.. The American journal of sports medicine, 2016. DOI: 10.1177/0363546515620383.

8. In 45 volunteers with no history of hip pain, symptoms, injury or surgery, blinded 3.0-T MRI found abnormalities in 73% of hips - labral tears in 69%, chondral defects in 24%, subchondral cysts in 16% and osseous bumps in 20%. A labral tear on MRI is therefore not by itself an explanation for hip pain.

   Register B, et al. — Prevalence of abnormal hip findings in asymptomatic participants: a prospective, blinded study.. American Journal of Sports Medicine, 2012. DOI: 10.1177/0363546512462124.

9. A JBJS systematic review screened 420 papers on intra-articular cellular therapy for knee OA and focal cartilage defects and found only SIX 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. Two products called 'stem cell therapy' at two clinics may share almost nothing.

   Chahla J, 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.. The Journal of bone and joint surgery. American volume, 2016. DOI: 10.2106/JBJS.15.01495.