How does a bone scan aid in determining the need for a corticosteroid (cortisone) injection?

From the Guidelines

Bone scans are essential in determining the appropriateness of cortisone injections by identifying areas of active inflammation in joints and bones, as they can help exclude osteomyelitis and other complications, with a high negative predictive value, as noted in the study by 1.

Key Points to Consider

• A bone scan uses a radioactive tracer that accumulates in areas with increased blood flow and metabolic activity, highlighting regions of inflammation or injury that may benefit from cortisone treatment, as described in the study by 1.
• This imaging technique is particularly valuable when clinical examination alone cannot pinpoint the exact location of inflammation or when multiple potential pain sources exist.
• For optimal results, cortisone injections should target areas with active inflammation rather than degenerative changes, as suggested by the study by 1.
• Typically, patients should wait at least 2-3 days after a bone scan before receiving a cortisone injection to allow the radioactive tracer to clear from the body.
• The information from bone scans helps clinicians deliver cortisone more precisely to the affected area, potentially improving treatment outcomes and reducing unnecessary injections, as noted in the study by 1.

Important Considerations

• Bone scans are just one tool in assessment, and clinical judgment remains essential in determining if cortisone injection is appropriate for a particular patient's condition, as emphasized in the study by 1.
• The accuracy of bone scans, either single phase or 3-phase, for diagnosing complications of lower extremity prosthesis is approximately 50% to 70% with a normal study, excluding a prosthetic complication as the cause of the patient’s symptoms, as reported in the study by 1.
• A 3-phase versus single-phase bone scan does not improve the accuracy of the test, as noted in the study by 1.
• The classic finding for an infected TKA is increased uptake on all 3 phases in the same location, but increased uptake is a nonspecific finding and may persist on a bone scan even as a postsurgical finding in the absence of infection, as described in the study by 1.

From the Research

Bone Scan and Cortisone Injection

• A bone scan can help determine the effectiveness of a cortisone injection by identifying areas of inflammation and bone activity 2, 3, 4, 5.
• The scan can show whether the injection has reduced inflammation and improved bone health, which can help guide further treatment decisions.
• However, the evidence on the use of bone scans to determine the effectiveness of cortisone injections is limited, and more research is needed to fully understand its role.

Mechanisms of Action

• Corticosteroids, such as those used in cortisone injections, have anti-inflammatory properties that can help reduce pain and swelling in affected joints 2, 3, 4, 5.
• The mechanisms of action of corticosteroids involve the inhibition of pro-inflammatory cytokines and the reduction of inflammation in the affected joint.
• However, the long-term effects of corticosteroid injections on joint health are not well understood, and further research is needed to determine their safety and efficacy.

Comparison with Other Treatments

• Studies have compared the efficacy of corticosteroid injections with other treatments, such as hyaluronic acid and platelet-rich plasma (PRP) injections 3, 4, 5.
• The results of these studies have been mixed, with some showing that corticosteroid injections are more effective in reducing pain and improving function, while others have found that PRP injections are more effective.
• Further research is needed to determine the relative efficacy of these different treatments and to identify the most effective treatment options for patients with osteoarthritis.

Safety and Efficacy

• The safety and efficacy of corticosteroid injections have been evaluated in several studies, with most showing that they are generally safe and effective in reducing pain and improving function 2, 3, 4, 5.
• However, there are potential risks and side effects associated with corticosteroid injections, such as infection, bleeding, and tendon rupture.
• Further research is needed to fully understand the safety and efficacy of corticosteroid injections and to identify the most effective treatment options for patients with osteoarthritis.