Knee pain is defined as a sensation of discomfort or pain in the knee, caused by overuse, poor form during physical activity and lack of proper warm up or osteoarthritis. The knee is coordinated with a number of surrounding structures, including bones, ligaments, tendons and cartilage to perform its functions. Any abnormality or external harm to any of these can result in knee pain.
Acute sudden pain is caused by fractures, sprained ligaments, tendon ruptures, meniscal injuries, knee dislocation or a dislocated kneecap. Chronic knee pain is commonly a sign of the different forms of arthiritis, bursitis, infection, gout.
Intra-articular steroid injections are a prescribed line of treatment for relief from joint-pain. Intra-articular injections with local anesthetics or corticosteroids can be used for the treatment of inflammation in the joint.
There are various types of steroids that can be used with intra-articular injections, which have a different duration of effect and action. The guiding principle which determines the effectiveness of each of these preparations is their solubility.
The insoluble preparations are known to have a longer duration of effect and are the most preferred. Aristospan is the most soluble and preferred preparation for intra-articular injections and its duration of effect is usually six months. Aristocort is also highly insoluble, and is usually second choice to Aristopan. This particular preparation normally has a duration of three months. Finally, Depo-Medrol is a highly soluble steroid that should only be used as a last resort. It only lasts for five weeks.
Before the procedure, the appropriate steroid is selected after careful consideration to the of the extent of the problem and patient history. A local anaesthetic (lidocaine 1%) is administered and the steroid is then injected into the joint. Once completed, an iodinated contrast is injected to observe immediate distribution of the steroid and local anaesthetic and confirm which joints are being treated.
Specialists dealing with intra-articular steroid injections generally instruct their patients to maintain a simple diary of pain for at least a week’s duration after the injection. The commonly recommended entry in the diary is pain vs. previously expected pain or same physical workload.
The intra-articular steroid injections are administered with the aim of providing two to six weeks of pain relief. However, the higher-dose steroids with or without joint lavage can provide pain relief for a period as long as 24 weeks.