Plantar fasciitis is a common source of heel pain, characterized by inflammation and irritation of the plantar fascia, the thick band of tissue running across the bottom of the foot from the heel bone to the toes. When conservative treatments like stretching and orthotics fail to provide relief, a cortisone injection may be recommended to manage severe symptoms. This procedure involves delivering a corticosteroid, a powerful synthetic anti-inflammatory medication, directly into the painful ligament insertion point. The purpose of this targeted injection is to reduce localized inflammation, alleviating pain and restoring function. The injection offers a window of opportunity for the patient to address the underlying causes of the condition.
Expected Timeline for Relief
Relief from a cortisone injection is generally not immediate, as the body requires time to process the medication. Many injections include a local anesthetic which provides rapid, but short-lived, numbness that wears off within a few hours. Following the initial procedure, a temporary increase in pain, often referred to as a “steroid flare,” can occur in up to 30% of patients, typically lasting up to 72 hours.
The corticosteroid’s anti-inflammatory effect usually begins three to seven days after the injection once the initial discomfort subsides. Significant pain reduction is typically short-term, often lasting between four and twelve weeks. While some patients may experience relief for up to six months, the effect tends to diminish after the three-month mark for most individuals. The goal of this temporary relief is to enable a patient to comfortably engage in physical therapy and stretching exercises, which are necessary for a lasting resolution of the condition.
Variables Influencing Effectiveness
The wide range in the duration of relief is heavily influenced by several patient and procedural factors. A patient’s adherence to post-injection care, including avoiding strenuous activity for a few days, is a significant determinant of success. Placing excessive stress on the treated tissue immediately after the procedure can counteract the anti-inflammatory action of the medication.
The severity and duration of symptoms before the injection also play a role, as more chronic conditions may not respond as robustly or for as long as acute cases. The technical precision of the injection matters; the use of ultrasound guidance can help ensure the medication is delivered accurately to the inflamed tissue, potentially improving outcomes and reducing complications. The specific chemical formulation of the corticosteroid used may also affect the onset and longevity of the anti-inflammatory effect.
Potential Side Effects and Limitations
While a cortisone shot offers powerful, localized pain management, it is a palliative treatment that manages symptoms but does not address the underlying biomechanical cause of plantar fasciitis. If the patient does not correct contributing factors, such as poor footwear or limited ankle mobility, the pain is highly likely to return once the steroid medication wears off.
The injection also carries specific risks, including a small chance of plantar fascia rupture. The corticosteroid may also lead to fat pad atrophy, causing a thinning of the natural cushioning under the heel that can result in chronic pain. Other local side effects include skin discoloration, such as whitening or thinning of the skin around the injection site.
Because of the potential for tissue damage, including fat pad atrophy and tendon weakening, physicians must strictly limit the frequency of injections. Repeated doses increase the risk of serious complications, including tissue necrosis. Therefore, cortisone shots are generally viewed as a temporary measure and are typically limited to a few injections per year or lifetime for the affected area.