Cortisone and other anti-inflammatory compounds have garnered a poor public reputation over the past several years. Often in current orthopedic Physical Therapy practice we are hearing more and more patients make statements against entertaining the possibility of incorporating corticosteroid injection into their plan of care in injury treatment. When asked why the individual is so adamantly opposed to an injection, we rarely hear a response other than “I hear it’s not good for you.” Well, it’s time to drop some education upon thee regarding this oft-maligned treatment and whether or not it deserves such a bum rap.

What is Cortisone?
The chemical cortisol or hydrocortisone is a hormone produced by the adrenal cortex, the outer layer of your adrenal gland. It is a naturally occurring chemical in the body that plays a crucial role in the regulation of major body functions, specifically glycemic metabolism, immune system function and inflammation. Part of a family of hormones called glucocorticoids, it is also made synthetically for use as an anti-inflammatory and anti-allergy agent and is commonly labelled as corticosteroids (prednisone, prednisolone and cortisone). Corticosteroids are not pain relievers. They reduce inflammation. When corticosteroids relieve pain, it is because they have reduced inflammation.

What is inflammation?
Inflammation is the process by which the body’s white blood cells, and substances they produce, eliminate the initial cause of cell injury, clear out necrotic cells and tissues damaged from the original insult and the inflammatory process, and to initiate tissue repair. Some of the chemicals released within the inflammatory process can act as pain-carrying nerve-fiber irritants resulting in localized pain.

So what’s the big deal about cortisone injection?
Conservative physical therapy treatment alone can be extremely beneficial in creating a tissue-healing environment in the body and assisting a person in the return to normal function. However, sometimes the body does not cooperate fully. Like many things in this world there are many variations to how a body responds specifically to injury. Everyone is not built that same, and while the vast majority of processes in the body are common throughout the population, there is range of actual responses and presentations within a process that varies from person to person. Much like we know sugar tastes sweet, but a teaspoon may be too sweet for some and for others a cup is bland. Or we know that Capsaicin is spicy-hot and for some a drop is too much, but others ask for a bottle and a straw.

Orthopedically, pain can be categorized as mechanical and inflammatory. All pain is from nerve irritation. No nerve activity, no pain. When a nerve is directly irritated by contact with an offending structure, like when a disc is compressing a nerve root in the spine or a partially torn rotator cuff muscle is being tugged on with active movement or the arm, the pain is often only present when the stress on the tissue is occurring.
Cortisone injection cannot DIRECTLY affect mechanical pain. In the case of inflammation, pain is cause by chemical irritation as stated above or related to fluid pressure compartmentalized in the part of the body that is injured, much like filling and then squeezing a water balloon in a confined space. The fluid pressure on the pain receptors (read nerve pain fibers) of the tissue create inflammatory pain. This pain often occurs after rest periods or when injured tissue is put on slack, allowing fluid pressure to build.

The nervous system is very complex. Nerves are what allow us to feel pain, touch, pressure, any and all sensation. Nerves also have another set of jobs such as carrying the signals that cause muscle activity and initiation of other active responses in the body. So when a nerve is irritated by inflammation, it often leads to a counter reaction from other types of nerves in an injured area that causes muscle spasm which create a form of mechanical pain.

So back to the previous statement “Corticosteroids are not pain relievers. They reduce inflammation. When corticosteroids relieve pain, it is because they have reduced inflammation.” Mechanical pain is not directly affected by cortisone injection, however, reduction of inflammation in a localized area can reduce the cause of mechanical pain caused by muscle spasm, thereby relieving symptoms INDIRECTLY in those cases.

Why is cortisone superior in some cases to NSAIDs or oral steroids?
A distinct benefit of a corticosteroid injection is that the relief of localized inflammation in a particular body area is more rapid and powerful than with traditional anti-inflammatory medications given by mouth. Your body also does not have to process injected medication as it does oral medication, guaranteeing a measured effective dose where it is needed. A single injection also can avoid certain side effects that can accompany many oral anti-inflammatory medications, notably irritation of the stomach.

Other advantages include the rapid onset of the medication’s action, dependability, and minimal side effects when compared to oral medication. Disadvantages of cortisone injections include the necessity of piercing the skin with a needle as well as potential short- and long-term side effects. It should be emphasized that though each of these side effects is possible, they usually do not occur.

Short-term cortisone injection complications are uncommon but include shrinkage (atrophy) and lightening of the color (depigmentation) of the skin at the injection site introduction of bacterial infection into the body (such as a joint infection), local bleeding from broken blood vessels in the skin or muscle soreness at the injection site aggravation of inflammation in the area injected because of reactions to the corticosteroid medication (post-injection flare)

Increased pain after the injection is typically due to a post-injection flare-up, because true allergies to cortisone are very rare.

Tendons can be weakened by corticosteroid injections administered in or near tendons. Tendon ruptures as a result have been reported, mostly in the Achilles tendon and in individuals with pre-existing conditions that can interfere with healthy tissue quality such as diabetes.

Generally, cortisone injections are used with caution in people with active infections. Long-term complications of corticosteroid injections depend on the dose and frequency of the injections and are very rare due to strict control of the dosage and frequency of injection by your doctor. It is generally felt that low, intermittent doses of corticosteroids pose little risk of significant side effects.

In summation, all injections are subject to a small percentage of risk due to the invasive nature of the procedure and strongly effective nature of the chemical injected. When used properly in cases of stubborn inflammatory symptoms while rehabilitating an injury, cortisone injection is a tool that can drastically reduce rehabilitation time and accelerate the ability of a person to progress strength and mobility, thereby returning earlier to full pain-free function. If you have concerns regarding any procedure that has been recommended to assist your rehabilitation from injury, do not hesitate to bring your concerns to a qualified medical professional. We are here to help. Be informed. Be Well.

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Windsor RE, Storm S, Sugar R. Prevention and management of complications from common spinal injections. Pain Physician. 2003;6:473–83. [PubMed]