FAQs on Knee Injections in Philadelphia
What conditions are treated with knee injections?
Knee injections are used to treat arthritis. Osteoarthritis (OA) is a joint disease that involves wear-and-tear, as well as inflammatory processes. Knee pain is the main symptom of OA, which results from cartilage degradation, degeneration of knee structures, and loss of synovial fluid. According to the Centers for Disease Control and Prevention (CDC), more than half of adults over the age of 65 years suffer from some form of arthritis.
What is the purpose of a knee injection?
Knee joint injections with aspiration are done to establish a diagnosis, drain excessive fluid, relieve discomfort, and instill medication.
What are the different types of knee injections?
- Corticosteroid injections – This medication modifies the inflammatory response, stops production of destructive enzymes, and restricts the action of inflammatory cells.
- Hyaluronic acid injection – This is an effective treatment for OA related to degenerative processes.
- Platelet-rich plasma (PRP) injection – This is done to promote healing of a damaged joint, improve function and relieve pain.
How do I prepare for the knee injection?
The nurse will go over the procedure and have you sign a consent form. You must change into a gown so the doctor will have access to the knee. Most patients are positioned lying down, with an absorbent pad beneath the knee. You can eat and drink the day of the procedure, but should bring someone to drive you home.
How is a knee injection performed?
The doctor will first cleanse the injection site with an antiseptic. The knee is inserted into the joint after numbing the skin. If excessive fluid is on the knee, the doctor may aspirate (draw off) the fluid before injecting the solution. After the injection, a bandage is applied to the injection site.
What can I expect after the knee injection?
Temporary soreness at the injection site is expected with both hyaluronic acid and corticosteroid knee injections. If the doctor adds an anesthetic into the joint, immediate pain relief can be expected. It typically takes 12-24 hours before the corticosteroid begins to work. With hyaluronic acid, the pain relief occurs after 48-76 hours. After the knee injection, you should rest for the remainder of the day, and avoid excessive weight-bearing activities.
What are the contraindications for the knee injection?
The pain specialist will not injection the knee if you have:
- A bacterial infection
- Severe bleeding disorder
- A joint prosthesis
- Overlying dermatitis
Do knee injections work?
In one review of studies, corticosteroids were found to offer short-term relief of OA pain, and hyaluronic acid injections offered 24 weeks of pain relief, as well as improved joint function. A recent study regarding hyaluronic acid found significant reduction of pain scores after the third injection compared to baseline pain scores. Several studies of knee joint injections show a 75-85% success rate. The few studies regarding PRP injections were promising for improved knee function, quality of life, and pain relief.
What risks and complications are associated with the knee injection?
As with all minimally invasive procedures, there are a few risks associated with this procedure. These include bleeding, infection, nerve damage, severe pain (hitting a nerve), and blood vessel injury.
Ayhan, E., Kesmezacar, H., & Akgun, I. (2014). Intraarticular injections (corticosteroid, hyaluronic acid, platelet rich plasma) for the knee osteoarthritis. World Journal of Orthopedics, 5(3), 531-561.
Godwin M & Dawes M (2004). Intra-articular steroid injections for painful knees. Systematic review with meta-analysis. Can Fam Phys, 50: 241-248.
Miller LE & Block JE (2013). US-approved intra-articular hyaluronic acid injections are safe and effective in patients with knee osteoarthritis: Systematic review and meta-analysis of randomized, saline-controlled trials. Clin Med Insights Arthritis Mus Disorders, 6, 57-63. doi: 10.4137/CMAMD.S12743
Shen, X. & Gatti, R. (2013). The safety and efficacy of intra-articular dual molecular weighted hyaluronic Acid in the treatment of knee osteoarthritis: the I.d.e.h.a. Study. Orthopedics Review, 5(4), e33.
Zuber, T.J. (2002). Knee joint aspiration and injection. American Family Physician, 66(15), 1497-1501.