Dr Harikrishna Yadoji, MBBS (Osmania), MS Ortho( NIMS), Fellowship in Arthroscopy (France )
Arthritis is not a single disease but a group of conditions that produce joint pain, stiffness and loss of function. For many patients, injections into the joint (intra-articular injections) are a useful tool, sometimes to alleviate pain enough to allow for meaningful physiotherapy, sometimes as a medium-term treatment when oral medications are inadequate, and occasionally as a bridge to more definitive surgery. In this blog, I discuss the common injection options, what high-quality research reveals today, practical pearls from clinical practice, persistent myths, and clear answers to the questions patients ask most frequently.
Short primer on what injections can/cannot do
Injections deliver medication directly into a joint space. That local delivery allows relief of pain with lower systemic exposure than oral drugs and can reduce inflammation inside the joint. They are tools: helpful for symptom control and function, rarely disease-curing (with a few experimental exceptions). Guidelines from major societies recommend the considered use of injections alongside exercise, weight management and other conservative care.
Common intra-articular injection mechanisms and evidence
1. Corticosteroid injections (steroids)
What they do: Powerful anti-inflammatory effect inside the joint; they work quickly.
Typical effect: Noticeable pain reduction within days, often strongest during the first 1–6 weeks; benefit commonly wanes after a few months. Repeated injections give repeated short-term relief but do not reliably slow the structural progression of osteoarthritis. PMC+1
Clinical pearl: Use for acute flares or when rapid relief is needed to allow rehabilitation. Avoid frequent repeat injections in the same joint spacing and conservative use to minimise potential cartilage effects.
2. Hyaluronic acid (viscosupplementation)
What it is: A gel-like lubricant naturally present in joints; injections aim to restore a degree of joint viscosity and reduce pain.
Evidence summary: High-quality meta-analyses show a small to moderate symptomatic benefit for knee osteoarthritis compared to placebo; benefit size and duration vary by preparation and patient selection. Several guidelines accept its use as an option after discussing realistic expectations.
Clinical pearl: Best results are usually in patients with mild-to-moderate knee OA, and when used as part of a multimodal plan (exercise, weight loss, physiotherapy).
3. Platelet-Rich Plasma (PRP)
What it is: An autologous concentrate of platelets from the patient’s own blood; thought to deliver growth factors that modulate inflammation and support tissue repair.
Evidence summary: Multiple randomised trials and meta-analyses report clinically meaningful improvements in pain and function (often lasting 6–12 months) in knee osteoarthritis compared with placebo or hyaluronic acid in many studies; however, study heterogeneity (preparation methods, dosing schedules) remains a concern. Safety is generally good but not uniformly risk-free.
Clinical pearl: If offered, choose a centre with standardised PRP protocols and sterile technique; counsel patients about variability in response and insurance coverage.
4. Emerging and experimental injections
Bone marrow aspirate concentrate, mesenchymal cell therapies and combinations (e.g., PRP + HA) are under active study. Early reports are promising in selected patients, but robust long-term data and regulatory clarity are still pending. Use within approved clinical pathways or trials when possible.
How to interpret the research practical takeaways
- Short-term relief vs long-term disease modification: Corticosteroids give predictable, short-term relief; PRP and HA may provide longer symptom relief for some patients, but none are definitively proven to halt osteoarthritis progression.
- Patient selection matters: Age, body mass index, radiographic stage of OA, activity expectations, and coexisting conditions affect likely benefit. Many injection studies show greater benefit in earlier stages of OA.
- Quality and standardisation: Particularly for biologics (PRP, cell therapies), variability in preparation protocols drives variability in outcomes — look for centres using standard, published methods.
Myths and facts
Myth 1: “An injection will cure my arthritis.”
Fact: No intra-articular injection currently cures osteoarthritis. Injections relieve symptoms and improve function for variable durations; they complement rehabilitation and lifestyle measures.
Myth 2: “Steroid injections always damage cartilage.”
Fact: Occasional concerns exist about repeated steroid injections and cartilage health, but when used judiciously and not excessively often, steroids are safe and effective for short-term symptom control. The decision to repeat should be individualised.
Myth 3: “PRP is completely safe and free.”
Fact: PRP uses your own blood, which reduces many risks, but post-injection flares, infection (rare), and inconsistent benefits can occur. Cost and lack of universal insurance coverage are important considerations.
Myth 4: “Hyaluronic acid is useless.”
Fact: Not true. Many patients experience meaningful pain relief; the magnitude is moderate, and patient selection influences outcome. Guidelines list it as an option after discussing expectations. BMJ
Q & A – what patients ask most
Q: Which injection is best for my knee OA?
A: There’s no single “best” option. For rapid flare control: corticosteroid. For longer symptom relief (months): HA or PRP may help in selected patients. Choice depends on the stage of OA, prior treatments, patient preference and cost considerations.
Q: How long will the relief last?
A: Corticosteroid: weeks to a few months. HA: commonly several months (varies). PRP: In many studies benefits last 6–12 months. Individual responses vary.
Q: How often can I get a steroid injection?
A: Most specialists avoid very frequent repeat injections to the same joint; common practice is to space them (for example, no more than 2–4 injections per year) and to reassess benefit vs risk at each visit.
Q: Do injections affect my chances for future knee replacement?
A: Current evidence does not show that appropriate use of intra-articular injections prevents or accelerates replacement surgery predictably; they are used to manage symptoms while exploring all treatment options. Decisions about joint replacement are made holistically.
Q: Are injections painful? Any serious risks?
A: Injections have short-term discomfort during the procedure; post-injection flare (temporary increase in pain) is common with biologics. Serious risks (infection, nerve injury, allergic reaction) are rare when performed with sterile technique and ultrasound guidance as needed.
How I counsel my patients (practical protocol)
- Assess thoroughly: confirm diagnosis, stage disease with X-ray/MRI if indicated, review comorbidities and medications.
- Set realistic goals: pain reduction and improved function — not a cure.
- Choose the injection after shared decision-making: discuss benefits, uncertainties, cost and alternatives.
- Use image guidance when anatomy is difficult: ultrasound or fluoroscopy increases accuracy for many joints.
- Follow with rehabilitation: injections work best when combined with physiotherapy, strengthening and weight management where applicable.
Final thoughts
Intra-articular injections are useful and evidence-based tools in the orthopaedic armamentarium for arthritis. They must be selected and delivered thoughtfully, with informed consent and clear functional goals. Recent high-quality studies and guideline updates (EULAR, AAOS and multiple meta-analyses) provide a rational framework for choosing between steroid, hyaluronic acid and biologic options such as PRP — but patient selection and realistic expectations determine success.