Steroid or hyaluronic acid injection for osteoarthritis of the Knee

Both steroid as well as hyaluronic acid are commonly used in the treatment of osteoarthritis of the knee.

Steroid injections work through complex processes, and they have powerful anti-inflammatory effects, which help to reduce the levels of inflammation of the joint in question. Pain levels will improve with the reduction in inflammation. Steroid injections can provide very quick relief, usually within days, and can last for many months. Steroid injection can be repeated this has to be done with care as you take too many repeat injections can cause damage to the tissues within the knee joint (cartilage).

Hyaluronic acid injections help to lubricate the joint. Hyaluronic acid injections are replicating the natural fluid that occurs in the knee joint. The length of time the people can benefit from these injections is variable and can range from a month to 6 months or so. The success is dependent on many factors including the degree of structural damage to needed degree of active inflammation of the knee et cetera.

Altman et al. (2015) did a systematic review into the mechanisms of action of hyaluronic acid injections for osteoarthritic knees (Altman, R.D., Manjoo, A., Fierlinger, A., Niazi, F. and Nicholls, M., 2015. The mechanism of action for hyaluronic acid treatment in the osteoarthritic knee: a systematic review. BMC musculoskeletal disorders, 16, pp.1-10.)

Key mechanisms of action reported:

Chondroprotection (protection of cartilage) was mentioned by 64.42 % of the articles used in the study. 67 of the studies included described Chondro protective effects of intra-articular hyaluronic acid treatment. Intra-articular hyaluronic acid has been shown to reduce chondrocyte apoptosis, while increasing chondrocyte proliferation.
Proteoglycan/Glycosaminoglycan synthesis was mentioned by 21.15 % and in 22 of the studies involved who mentioned the enhanced proteoglycan and glucosamine glycan synthesis related to intra-articular hyaluronic acid treatment. As osteoarthritis progresses intrinsic proteoglycan and GAG concentrations decline within the cartilage. Results demonstrated that intra-articular hyaluronic acid treatment stimulated proteoglycan synthesis delaying the progression of osteoarthritis.
Anti-inflammatory effects were mentioned by 20.19 % in 21 of the identified studies the anti-inflammatory effects of intra-articular hyaluronic acid treatment was mentioned. IL-1β is known to demonstrate pro inflammatory effects and suppression of IL-1β by hyaluronic acid provides anti-inflammatory effects.
Mechanical effects were mentioned by 9.61 % or 10 of the studies that were included describe mechanical effects of hyaluronic acid in the treatment of osteoarthritis of the knee. Fiscus nature of hyaluronic acid treatment is shown to lubricate joint capsule preventing degeneration through decreased flexion. Hyaluronic acid further protects the joint capsule through beneficial shock absorption effects. Hyaluronic acid provides cushioning to absorb pressure and vibration within the joint that otherwise would lead to chondrocyte degeneration.
Subchondral Bone was mentioned by 7.69 % Or 8 of the included studies. He has been shown that interaction between subchondral bone osteoblast and articular cartilage is chondrocytes in osteoarthritic joints alters. Several enzymes play a role in collagen degradation as well as cartilage degradation. Intra-articular hyaluronic acid affects the subchondral bone mainly by suppression of these enzymes.
Analgesic was mentioned by 5.76 % or 6 of the included articles described significant decrease in pain associated behaviour with a single hyaluronic acid injection in a murine model. One of the studies suggested that hyaluronic did not directly bind to bradykinin receptors but provided analgesic effects through interactions with hyaluronic acid in the receptors and free nerve endings within the joint tissue.

Steroid Injections

Steroid injections are often used due to their fast course of action

Through complex processes, steroids have powerful anti-inflammatory effects, which help to reduce the levels of inflammation of the joint in question. In most cases accurately administered steroid injections can provide pain relief often within 24 to 48 hours. Joint mobility can rapidly improve due to reduction of inflammation and pain which in turn helps function. Steroid injections due to being administrated locally have fewer side effects then oral steroids.

Known side effects of steroid injections: Depigmentation of skin post injection, repeated steroid injections can cause cartilage damage. Steroid injections can weaken tendons and increase the risk of tendon rupture in some cases. People may experience facial flushing which usually last for a few hours. There is also very rare possibility of an infection following a steroid injection which is uncommon and thought to be in the order of 4.6 per 100,000 injections.

Other injection related risks are neurovascular injury which can occur with any injection and is not specifically related to steroid injection

Conclusion: Which is better: Steroid or Hyaluronic acid injection?

Both steroid and hyaluronic acid injections are commonly used to treat osteoarthritis of the knee, but they work in different ways and have distinct benefits and drawbacks.

I would generally recommend steroid injections in scenarios where there is a very high level of pain making function difficult. Often there is then also a significant degree of inflammation present in many cases with effusion and neovascularity on ultrasound. In those cases, and of course if there is no contraindication, I would favour steroid injection. As this tends to act rapidly with significant pain relief which can be sustained for many months.

If levels of function are slightly better and pain levels are more modest and structural changes to the joint are mild to moderate, then hyaluronic acid injection can be a very good option.

One very important thing to remember is that steroid injections come with potential side effects as listed above and those side effects tend to become more frequent the more often steroid injections are given in the same structure. Hyaluronic acid injections do not have this drawback and can be repeated if successful an infinite number of times.

References:

Altman, R.D., Manjoo, A., Fierlinger, A., Niazi, F. and Nicholls, M., 2015. The mechanism of action for hyaluronic acid treatment in the osteoarthritic knee: a systematic review. BMC musculoskeletal disorders, 16, pp.1-10.

Bilsborough Smith, C., Baker, D., Botchu, R., Cairns, M., Chester, R., Dean, B., Mast, R. and Lewis, J., 2023. Corticosteroid injections for non-spinal musculoskeletal conditions. Consideration of local and systemic adverse drug reactions and side effects. New Zealand Journal of Physiotherapy.

Holland, C., Jaeger, L., Smentkowski, U., Weber, B. and Otto, C., 2012. Septic and aseptic complications of corticosteroid injections: an assessment of 278 cases reviewed by expert commissions and mediation boards from 2005 to 2009. Deutsches Ärzteblatt International, 109(24), p.425.