What are Knee Joint Injections?
Knee pain as a result of osteoarthritis of the knee is one of the leading causes of disability in the United States. It develops slowly and the pain it causes worsens over time. Although there is no cure for osteoarthritis, there are many treatment options available to help people manage pain and stay active. Clinicians frequently rely on knee joint injections to treat knee pain and stiffness associated with inflammation. Acute and chronic knee pain results in a decrease in joint mobility that often leads to a reduction in daily activity. This can ultimately affect the physical health and emotional well-being of a patient.
Physicians have several types of knee joint injectionsavailable. The type of injection typically depends on the nature of the knee injury.
The most common type of knee injection for inflammation is corticosteroids; however, some other available injections include:
- Hyaluronic acid used to cushion and lubricate the knee join.
- Viscosupplementation is a procedure in which a thick fluid called hyaluronate is injected into the knee joint. it is thought that hyaluronate will improve the lubricating properties of the synovial fluid, reduce the pain from osteoarthritis of the knee, improve mobility, and provide a higher and more comfortable level of activity. If you have tried all other nonsurgical treatment methods and your pain continues to limit your activities, viscosupplementation may be an option.
- Platelet Rich Plasma (PRP) used to inject the patient’s own blood plasma enriched with platelets to induce healing.
Physicians utilize the different types of knee injections to treat a variety of broadly categorized types of knee pain. Understanding the anatomy of the knee may help shine some light on why and how knee joint injections can help decrease pain.
The knee is essentially composed of four bones: the femur, tibia, fibula, and patella. All four of these bones work in concert to aid the knee during movement. There are also muscles involved during flexion and extension of the knee. The muscles include the hamstrings, which support the back of the knee, and the quadriceps, which support the front of the knee.
Ligaments and cartilage help stabilize the knee. The two cruciate ligaments located at the center of the knee joint are the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL). Both of these ligaments assist the knee during rotation. The lateral and medial ligaments also support the knee, and the lateral and medial meniscus cartilage acts as a cushion between the femur and tibia.
Injuries and knee pain can manifest in any one of the aforementioned anatomical structures. For example, a rapid twist of the knee during sports or other activity could cause tendon injury, while degeneration of the cartilage over time may be the cause of inflammation and associated pain. A proper diagnosis through patient assessments and imaging studies will help physicians determine which underlying condition is present prior to the knee joint injection.
How are Knee Joint Injections Performed?
Prior to the procedure, the patient’s skin is cleaned in preparation for the injection. After the skin is sterilized, a local anesthetic is used as a numbing agent along with a long-lasting steroid medication.
Prior to a platelet rich plasma injection, the physician draws blood from the patient. A centrifuge machine is used to separate the plasma from the blood. The plasma is then injected into the knee. During the injection, the doctor uses a special real-time x-ray, known as a fluoroscope, to guide the needle to the correct location.
Corticosteroid injections have been successfully used in the management of knee-related pain and have been the topic of many investigations concerning their efficacy. A systematic review of 28 randomized controlled trials, in one year, of corticosteroid injections for knee pain confirmed short-term pain relieving benefits in each one of the trials.
Studies regarding the injection of hyaluronic acid into troubled knee joints also revealed favorable results. During a recently reported meta-analysis, hyaluronic acid injections resulted in positive therapeutic effects for patients who suffered from knee pain related to osteoarthritis.
A 2010 edition of Knee Surgery, Sports Traumatology, Arthroscopy also reported successful treatment of knee pain from platelet rich plasma injections. According to the authors of this study, researchers conducted statistical analysis on patients who were administered platelet rich plasma injections for knee pain. At the conclusion of the study, the analysis showed significant improvement in pain relief in patients who received the platelet rich plasma injections compared to that of the placebo group.
Knee joint injections are considered safe, non-invasive procedures; however, as with all procedures, there is some risk of complications. Although rare, potential risks includ
Conditions Related To Knee Joint Injections
Knee pain is a very common occurrence in the United States. Most cases of knee pain can be attributed to osteoarthritis. The Centers for Disease Control and Prevention have reported that arthritis occurs in approximately 50% of people over the age of 65. Osteoarthritis is characterized by cartilage degeneration that ultimately results in pain and inflammation.
Although knee joint injections cannot prevent osteoarthritis, doctors frequently rely on them as part of an overall conservative approach to help manage the pain associated with the disease. In addition to pain associated with osteoarthritis, knee joint injections have also proven useful for various causes of knee pain, such as tendonitis, cartilage tears, gout, and bursitis.
Knee joint injections are a conservative option for treating knee pain. This well-established nonsurgical treatment has been the subject of many studies that have shown favorable results concerning its safety and efficacy. Successful knee joint injections afford patients the opportunity to return to activity again and allow for highly-effective pain relief in an outpatient setting.