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Introduction

Corticosteroid injections (also known as ‘cortisone injections’) are commonly used by sports physicians to treat musculoskeletal injuries; they can help reduce pain, swelling and stiffness.

Corticosteroid injection into joints (with hydrocortisone acetate) dates back to 1951, when it was performed by Dr Joseph Hollander and his colleagues. Their work involved 1,300 patients and over 10,000 hydrocortisone injections to various joints and soft tissue (such as bursae and tendon sheaths) over a period of 4 years!^1,2

Things have changed a lot since those days. Up to 15 years ago, it was corticosteroids that were injected for most musculoskeletal conditions, essentially making it ‘the tool for every job’. This worked well for some conditions, but was sometimes associated with side effects, especially if a patient was given repeat corticosteroid injections in quick succession.

Side effects are generally uncommon, but can include localised skin pigmentation changes, lipoatrophy, calcification around the joint, allergic reaction to the constituents, tendon rupture, avascular necrosis, infection and systemic side effects.

The most common side effect to occur is a ‘steroid flare’, thought to affect up to 1 in 20 patients injected. This is an acute exacerbation of pain within 1-2 days of having the injections. Fortunately, it generally subsides quickly with a combination of rest, ice and oral anti-inflammatory medication (NSAIDs).

What can corticosteroid injections be used to treat?

The following parts of the body can be injected – joints, tendon sheaths, ligaments, muscles, musculotendinous junctions and the intermuscular plane. In the spine, areas that can be injected include the epidural space (epidural injections), facets (facet joint injections) and intraforaminal spaces (nerve root injections).

There are some areas where corticosteroid injections should be avoided, such as directly into tendons, nerves or vascular structures. Increasingly, there is a move away from injecting corticosteroids for tendinopathy (e.g. Achilles tendinopathy) as these conditions are primarily degenerative in nature, not inflammatory. There is also a concern about repeated injections increasing the risk of a tendon rupture.

A wide range of clinical conditions may benefit from a corticosteroid injection. Examples include carpel tunnel syndrome, De Quervain’s tenosynovitis, osteoarthritis, gout and rheumatoid arthritis. Spine conditions include degenerative disc disease, facet joint arthritis and nerve root entrapment.

Injections were traditionally given using anatomical landmarks as a guide (landmark-guided injections). With the advances in imaging, more and more clinicians choose to do these injections under imaging guidance (using an ultrasound, x-ray or CT to visualise the needle and area to be injected) for reasons of accuracy and safety.

How do corticosteroids work?

Corticosteroids work in many ways to achieve their effects. These include reducing the inflammatory reaction, restricting accumulation of leucocytes and macrophages (types of white blood cells) and inhibiting enzymes that can destroy normal tissue indiscriminately.

Additionally, new research suggests that corticosteroids may help to reduce the formation of ‘prostaglandins’, which are known to cause pain.

Importantly, the act of introducing a needle to injured tissue may in itself provide drainage and release of pressure. It may also mechanically disrupt scar tissue in muscle.

What do corticosteroid injections consist of?

Corticosteroid injections commonly consist of the following medications: a corticosteroid (e.g. methylprednisolone/triamcinolone acetonide/hydrocortisone) and a local anaesthetic (e.g. short-acting lidocaine or long-acting bupivacaine).

The local anaesthetic component may be injected first to reduce pain for the patient.

Other options for treating musculoskeletal injuries

There is now a greater awareness of other injection options. These include hyaluronic acid injections for arthritic joints, prolotherapy injections for treating lax ligaments and platelet-rich plasma (PRP) injections for tissues that have poor healing properties.

In recent times, stem cell injections have become popular due to their proposed regenerative properties. However, more research is needed on its effectiveness and safety profile before it can be used more widely.

‘Non-injection’ therapies are also available for treating musculoskeletal injuries. For example, there is a lot of research to support the use of shockwave therapy (SWT) for chronic tendon and soft tissue injuries. It is also more acceptable to patients who are needle phobic and would much prefer to avoid injections!

Finally, there is a greater emphasis on the multi-disciplinary team (MDT) approach, rehabilitation and prevention. Injections on their own, without counselling or referral for appropriate rehabilitation to physiotherapy and other allied health colleagues, is often associated with poorer clinical outcomes.

Public perception

It may be helpful to mention that corticosteroids (which this article refers to) and anabolic steroids (which are used illegally as an ergogenic aid to stimulate muscle mass and therefore banned by anti-doping authorities) are not the same!

References