Corticosteroid injections, often called cortisone shots, are a common medical treatment used to manage localized pain. These injections deliver a synthetic version of the natural hormone cortisol directly into a specific area, such as a joint, tendon sheath, or the spine. They are used to treat conditions involving inflammation, including various forms of arthritis, bursitis, and tendon issues. When an injection fails to provide the expected relief, it points to several underlying factors beyond the medication itself.
Understanding the Function and Timeline of Steroid Injections
The fundamental action of a corticosteroid is to act as a potent anti-inflammatory agent by suppressing the local immune response. It calms the overactive cells causing swelling and irritation in the targeted tissue, which reduces pain. Crucially, the injection does not heal or repair underlying structural damage; it provides an environment of reduced inflammation for healing or symptom management.
Many injections include a local anesthetic, which provides immediate, but temporary, numbing relief. This quick cessation of pain can sometimes mistakenly be attributed to the steroid itself. The corticosteroid component is slow-acting and typically takes between 24 to 72 hours to begin its anti-inflammatory work.
Full therapeutic effect often requires five to seven days, and sometimes up to two weeks, to notice the maximum benefit. If no improvement is felt within this initial two-week period, it is considered a non-response. The duration of successful relief is highly variable, lasting from a few weeks to several months, depending on the condition and individual response.
When the Pain Source Is Not Primarily Inflammatory
A common reason an injection fails is a misdiagnosis or an incomplete understanding of the pain’s true origin. Steroids address inflammation, but pain can arise from sources that do not involve a treatable inflammatory process. For example, many overuse tendon injuries are degenerative conditions, termed tendinopathy, which lack the acute inflammation corticosteroids are designed to treat.
In cases of advanced structural joint damage, such as severe osteoarthritis, the pain is predominantly mechanical, caused by bone-on-bone friction or cartilage loss. While an injection may reduce co-existing inflammation, it cannot repair this structural defect, so relief is often minimal or absent. Similarly, pain from severe nerve compression, like a large disc herniation or spinal stenosis, is caused by physical pressure, and the steroid may be unable to alleviate the mechanical compression.
Many musculoskeletal issues stem from underlying biomechanical problems, such as poor movement patterns or muscle imbalances, which cause secondary irritation. The injection relieves the symptom but fails to correct the root mechanical cause. Temporary relief, if achieved, quickly fades as the mechanical stress continues to irritate the joint or tendon.
Variables Affecting Injection Success
Even with a correct diagnosis, the procedure introduces several variables that impact the outcome. A major factor is the accuracy of needle placement, which is paramount for the medication to reach the precise target tissue. If the medication is injected into a neighboring area or disperses too widely, the concentration at the site of inflammation may be too low to be effective.
To maximize accuracy, many physicians use real-time imaging guidance, such as ultrasound or fluoroscopy, ensuring the injection is delivered exactly where needed. Without this guidance, the success rate for deep or complex joints can be significantly reduced. The specific corticosteroid medication used and its potency also play a role, as different formulations have varying strengths and durations of action.
Individual biological factors heavily influence how a patient responds to the drug. Some people have a unique metabolism that processes and clears the steroid too quickly, shortening the therapeutic window. Patients with certain psychosocial factors, such as high levels of negative affect, have also been shown to experience less pain reduction following an injection.
Guidance for Follow-Up Care
If a steroid injection fails to provide measurable relief within two weeks, schedule a follow-up consultation with the physician to discuss next steps. This consultation should involve a review of the initial diagnosis and whether the pain source was correctly identified. The physician may also review the exact procedure details, including whether image guidance was used.
A failure to respond indicates that the underlying issue requires a different therapeutic approach. Physical therapy is often the next logical step, as it directly addresses mechanical issues, muscle imbalances, and movement patterns that may be the true cause of the pain. Alternative treatments, such as platelet-rich plasma (PRP) injections or nerve blocks, may also be considered depending on the suspected diagnosis.
It is helpful for patients to keep a brief pain log, documenting symptom severity and any changes in function following the injection. This documentation provides objective data that helps the medical team decide whether to pursue a second injection, which is sometimes necessary, or move toward a more definitive treatment path, potentially including a surgical consultation.