What injections are available for knee osteoarthritis, and which one is more suitable for me?

Common options include hyaluronic acid, PRP, corticosteroids, and combined injections. In the study, combined PRP plus hyaluronic acid was associated with more stable data for long-term improvement, hyaluronic acid had few side effects, and corticosteroids were suited to short-term pain relief in the acute phase. The actual choice depends on the degree of degeneration, age, allergy history, cost, and insurance conditions, and should be decided after discussion with a physician based on your condition and a physician's assessment.

Is PRP injection covered by insurance, and how many injections are needed?

PRP is currently not covered by Taiwan's National Health Insurance and is paid out of pocket. A course usually involves 1 to 3 injections; some studies used one injection per week for 2 to 3 consecutive weeks, and others used a single injection. National Health Insurance covers hyaluronic acid injection only when osteoarthritis criteria are met and after 6 months of follow-up.

Why is repeated long-term use of corticosteroid injection not recommended?

Corticosteroids reduce inflammation and relieve pain quickly in the short term, but the effect usually lasts only a few weeks to 3 months. Research suggests that repeated long-term injection may harm cartilage and be associated with faster degeneration; in some follow-up comparisons, the corticosteroid group even improved less than a saline placebo group, so corticosteroids are recommended for short-term use only. These are trial results and do not predict any individual's outcome.

Ranking Injection Treatments for Knee Osteoarthritis: PRP, Hyaluronic Acid, and Corticosteroids for the Long Term

A 2025 network meta-analysis covering 37 clinical trials and a total of 5,089 patients with knee osteoarthritis indicated that three common injection therapies, platelet-rich plasma (PRP), hyaluronic acid (HA), and corticosteroids (CS), along with their various combinations, differed in long-term treatment results (follow-up of at least one year).

For the PRP injection protocols in the study, most used a course of 1 to 3 injections. Some trials scheduled one injection per week for 2 to 3 consecutive weeks; others used a single injection. These studies did not use a uniform brand, and preparation methods also differed slightly (both manual centrifugation and commercial kits were used).

Hyaluronic acid (HA) treatment mostly involved 3 to 5 injections, usually spaced one week apart. A few studies used a single high-dose injection (such as a single 60 mg injection). HA molecular weight ranged from low (500 to 730 kDa) to high (6,000 kDa).

Treatment Group One: Combined PRP plus Hyaluronic Acid Injection

In the study, combining PRP and hyaluronic acid showed more stable data in the trials with one-year follow-up. Hyaluronic acid increases lubrication in the joint and reduces friction, while PRP contains growth factors the body uses for repair, which may help the repair of damaged cartilage tissue; using the two components together may show a synergistic effect.

The data showed that one year after injection, the pain score (measured on the visual analog scale, VAS) decreased by an average of 24.4 points (on a scale of 0 to 100), and the function score (total WOMAC score) improved by 16.1 points, making it the group with more stable results in this study.

Treatment Group Two: PRP Alone

If hyaluronic acid is not acceptable, PRP alone can also be chosen. This treatment, concentrated from the patient’s own blood, may help improve symptoms by promoting new tissue growth and reducing inflammation within the joint. For younger patients whose joints have not degenerated severely, it is often included among the clinical treatment options.

In the study, one year later, PRP alone reduced the pain score by an average of 19.5 points, and the function score improved by about 14.6 points, placing it in the middle range of results in this study.

Treatment Group Three: Hyaluronic Acid Alone

Hyaluronic acid is often seen in skincare products, but it actually exists naturally within the joint. Injecting hyaluronic acid increases joint lubrication, making movement less painful. In the study, at one year, patients’ mobility and pain both improved. Hyaluronic acid has few side effects and low treatment risk, making it suitable for those who do not want PRP or other therapies, or who meet the conditions for insurance coverage.

The data indicated that after hyaluronic acid treatment the pain score improved by an average of about 6.2 points and function improved by 5.6 points, a mild effect.

Treatment Group Four: Corticosteroid Injection

Corticosteroid injection is usually used during acute pain, as it can reduce inflammation and relieve pain quickly. However, the study showed that this effect usually lasts only a few weeks to 3 months and does not provide long-term improvement. Repeated long-term corticosteroid injection may harm the joint cartilage and be associated with faster degeneration.

In the one-year follow-up results, corticosteroids improved pain by only 1.85 points and function by about 3 points, making it one of the more limited groups in this study.

Notably, in some comparisons, plain saline injection (used as a placebo) produced long-term improvement comparable to or greater than corticosteroids. This suggests that although corticosteroids can reduce inflammation in the short term, they are not suited to repeated long-term use.

Strengths and Limitations of the Study

This NMA included RCTs with at least one year of follow-up, providing a more comprehensive assessment of long-term outcomes. By including a broader range of studies, a larger sample size, and stricter inclusion criteria, it improved the reliability of the results, reduced variability, and strengthened statistical power and the generalizability of the findings.

The study acknowledged limitations, including a small number of direct head-to-head trials, small sample sizes in some studies (40% of studies had fewer than 100 patients), and about 10% of studies having a high risk of bias and low methodological quality. In addition, the study did not use the safety of intra-articular injection as an outcome measure, and physical therapy may have influenced the final results. Differences in PRP preparation protocols, HA formulations, CS dosing regimens, and outcome measures may also have contributed to heterogeneity.

How to Choose an Injection Based on Degree of Degeneration

The data included in this large study showed that different treatment approaches, combined PRP plus hyaluronic acid, PRP alone, and hyaluronic acid alone, gave different clinical results in improving knee pain and slowing degeneration. A physician will discuss a suitable treatment strategy together with the patient based on the patient’s age, degree of degeneration, medical history, and lifestyle needs. Corticosteroids should be used cautiously because of long-term risks, and long-term reliance on them is not recommended.

Although injection treatment is not suitable for everyone, patients are advised to discuss it with a physician first, assess their own degree of joint degeneration and lifestyle needs, and then decide whether to receive treatment. Combined with appropriate exercise and weight control, this can help keep the knee healthier and movement more comfortable. Whether treatment is suitable depends on your condition and a physician’s assessment.

Who Is Suitable for Intra-articular Injection?

Suitable group: those roughly 40 years and older, with moderate knee degeneration, pain when walking or going up and down stairs, and who are not yet considering surgery.
Unsuitable group: those with septic arthritis, severe bleeding problems, or a history of allergy to the injected medications.
Number of sessions: PRP usually requires 1 to 3 sessions, and hyaluronic acid about 1 to 5 sessions; the physician will adjust according to the situation.
Cost and insurance: PRP and hyaluronic acid are not necessarily covered by insurance in some countries, so it is advisable to ask in advance. Under Taiwan’s National Health Insurance, after using rehabilitation and medication for osteoarthritis and completing at least six months of follow-up, insurance-covered hyaluronic acid injection can be used; while it does not provide the top two treatment options, it can still be a reasonable choice.

Through the latest research, it is possible to choose a suitable injection therapy with more confidence. Although the knee degenerates, treatment methods keep advancing, and with early management there is an opportunity to slow the progression and improve quality of life. The actual choice depends on your condition and a physician’s assessment, and these are trial results that do not predict any individual’s outcome.

References

Gupta, N., et al. (2025). Long-term effectiveness of intra-articular injectables in patients with knee osteoarthritis: a systematic review and Bayesian network meta-analysis. Journal of Orthopaedic Surgery and Research, 20:227.