What is the point of joint injections? Sticking a needle into a joint is not anyone's idea of a good time; however, at times, an injection might be the best option despite the risks and discomfort. Knowing the risks of bleeding and infection, millions of people put up with the pain of this invasive procedure. Avoiding the needle would be ideal; however, the needle does provide an access route for the fluids being injected into the joint. The results of a joint injection depend on the type of substance being injected, the accuracy of the injection, and location of the injection. The whole point in having an injection depends on the results.
In order to understand the purpose of a joint injection, one must first have some basic understanding about the joint itself. The joint is sealed into an encapsulated, confined space by the synovial joint capsule. Any fluid injected into the joint capsule stays within the joint and does not disperse throughout the entire body. All of the joint structures like the ligaments and tendons are closing intertwined with the capsule and together provide stability for the bones which are joining together to form the joint. In turn, The joint capsule is also closing related to joint problems like bone spurs, adhesive capsulitis, intra-articular crystals and arthritis. Thus, any therapeutic fluid injected into the joint capsule has the potential to relieve many types of joint problems.
Two main types of substances are used in joint injections. Steroids are the most common chemical injected because of their powerful ability to control inflammation. By cooling down the fire in a joint, the pain and swelling can be reduced to the point that joint function can return to normal. The second most common substance injected into the joint is Hyaluronic Acid. It is a basic building block of connective tissues found in the joint like the cartilage and synovial lining. When injected into a joint as a joint supplement, this substance is said to improve joint function by improving joint lubrication and shock absorbency. Both steroid and Hyaluronic Acid are proven effective, but Hyaluronic Acid seems to be gaining popularity.
The injection of Hyaluronic Acid is called Viscosupplementation and is well proven to be effective for knees. After three to five weekly injections, one can expect pain relief within a month that can last up to a year. Hyaluronic acid is favored over steroids because the pain relief does seem to last longer and does not have the risk of joint deterioration with multiple, repeated injections. However, the worth of viscosupplementation has not been proven in the hips, shoulder, thumb or ankle while steroids are known to be effective in any joint.
The effectiveness of a joint injection is not only dependent on the type of fluid injected, but also on the accuracy of the needle placement. In order to improve the accuracy of joint injections, many doctors are starting to use ultrasound guidance in the office. Anyone with a poor response to traditional, exam-guided injections is encouraged to have an ultrasound guided injection because improved accuracy does improve the results.