Project Description

Dr. Paul Lynch, performs a synvisc knee injection to help lubricate the knee joint, ultimately relieving the patient’s pain.


Watch Pain Doctor Paul Lynch perform a Synvisc Knee Injection procedure live.


What Are Knee Joint Injections?


Chronic knee pain is common and previous studies have indicated that nearly a quarter of all adults suffer from symptoms of knee pain. The symptoms of pain can vary widely and range from a dull ache to a sharp stab. Whether these symptoms are acute or chronic in nature, they have the potential to lead to significant impairments on the patient’s day-to-day functioning.

Symptoms of knee pain may be accompanied by:

  • Redness
  • Swelling
  • Instability of the knee
  • Immobilization
  • Trouble straightening the knee
  • Trouble bending the knee

When considering treatment options, the most important factor is the underlying source of the pain. Many patients suffering from knee pain are expected to achieve relief from these symptoms through the use of more conservative methods first. For instance, over-the-counter (OTC) non-steroidal anti-inflammatory drugs (NSAIDs) are regarded as quite effective for managing symptoms of pain, owing to their anti-inflammatory properties. Nonetheless, a small portion of patients are not able to achieve symptom relief from these conservative methods, and as such, may be excellent candidates for knee joint injections.

There are several types of knee joint injections. Broadly, these injections differ in the solution that is injected into the knee joint area, including:

  • Corticosteroids: Corticosteroids can be effective in reducing knee joint pain, owing to their anti-inflammatory properties.
  • Hyaluronic acid: Hyaluronic acid is a substance that is found to naturally occur in the joint of the knee. The function of this substance is to lubricate the structures that comprise the joint so that it moves smoothly. It also acts as a protective cushion against possible trauma or injury. As individuals age, this protective cushion may break down, causing a reduction in the amount of hyaluronic acid within the joint. Thus, supplementing this substance through knee joint injections helps reduce the irritation and inflammation that leads to symptoms of pain and discomfort.
  • Platelet rich plasma: A patient’s own blood plasma, containing a high concentration of platelets, can be used to treat pain and discomfort of the knee joint. Platelets release proteins known as growth factors, which are critical to the process of tissue repair and regeneration within the body.

The procedure for knee joint injections is regarded as non-invasive. They are typically performed on an outpatient basis and can be performed in under an hour. As with most medical procedures, knee joint injections do carry some risk for adverse side effects.

These side effects are generally rare and can include:

  • Swelling of the joint area or bruising
  • Pain at the injection site
  • Bleeding at the injection site
  • Allergic reaction
  • Inflamed synovium
  • Flushing of the face
  • Saphenous neuropathy
  • Septic or acute aseptic arthritis
  • Albicans arthritis
  • Nicolau syndrome

Despite these risks, knee joint injections have received support for their pain relieving benefits for knee joint pain. Typically, these effects can be seen within one to two days of the procedure. Furthermore, most patients report that they remain generally free from symptoms for around six to 12 weeks. In a small portion of cases, the patient’s knee pain does not completely resolve following this initial injection. In these instances, the physician may recommend two to three follow-up injections until the patient is no longer in discomfort due to the pain.


How Is A Knee Joint Injection Performed?


The knee is regarded as one of the more complex joints within the body. It is comprised of four bones: femur, fibula, tibia, and patella. These bones are secured together within the knee by various ligaments and cartilage. Further, tendons in the knee serve to attach the various leg muscles (including calf muscles, quadriceps, and hamstring) to the bones. All of the structures that comprise this complex knee joint are at risk for trauma or injury.

Managing symptoms of knee pain as the result of injury can be challenging. Your physician will want to carefully consider the source of the pain in order to determine the appropriate available treatment options. In general, most instances of knee joint pain are attributable to irritation and inflammation of the soft tissue, which can be effectively managed through knee joint injections.

During this procedure, the surface of the skin at the site of the injection will be thoroughly cleaned and sterilized. Most knee joint injections will require only a topical local anesthetic; however, an intravenous sedation medication may be employed in order to keep the patient comfortable during the procedure.

To begin, the physician uses a fluoroscopic X-ray device to assist in guiding the injection needle into the proper location within the knee joint. Once the needle has been correctly placed, the solution (i.e., corticosteroid, hyaluronic acid, or platelet rich plasma) is injected into the affected area, and both the injection needle and the fluoroscopic device are removed.

Given that the patient’s own blood is used for platelet rich plasma injections, this procedure specifically requires that the physician take a blood sample prior to performing the injection. The sample of blood, which is contained in a vial, is placed into a centrifuge. This machine spins the vial at a very high rate, causing the red and white blood cells to be separated from the plasma. The patient’s plasma is drawn off and used for the injection.


Conditions Related To Knee Joint Injections


Knee joint injections are not intended to prevent knee pain or injury. They are only used to treat symptoms of knee pain and discomfort that have been unresponsive to previous trials of more conservative methods of pain management (e.g., oral analgesics). Acute and chronic knee pain is a commonly occurring complaint among outpatient clinics within the United States and a large portion of these cases of knee pain can be attributed to osteoarthritis.

Osteoarthritis is a degenerative disease in which, over time, the soft tissue of the joint begins to suffer the effects of daily wear and tear. This can cause the structures of the joint to become irritated and inflamed. Knee joint injections have received support as being effective in managing these symptoms.

Knee joint injections can be used to treat the symptoms of other conditions, including:

  • Tendinitis
  • Cartilage tear
  • Gout
  • Bursitis
  • Other forms of injury or trauma to the structures comprising the knee




Knee joint pain is quite common within the United States. In many cases, patients may be able to effectively manage their symptoms of pain using more conservative methods, such as oral analgesics. However, a portion of knee pain patients will report symptoms that do not seem to improve using these treatment techniques. For these patients, knee joint injections may be warranted. There have been a number of studies that have examined the effectiveness of these injections and provided support for their use in treating the symptoms of conditions affecting the knee.



  1. Kon E, Buda R, Filardo G, Martino A, Timoncini A, et al. Platelet-rich plasma: intra-articular injections produced favorable results on degenerative cartilage lesions. Knee Surg Sports Traumatol Arthrosc. 2010;18:472-479.
  2. Leung A, Liew D, Lim J, Page, C, Boukris-Sayag V, et al. The effect of joint aspiration and corticosteroid injections in osteoarthritis of the knee. Int J Rheum Dis. 2011;14:384-389.
  3. Lockman, L. Knee joint injections and aspirations. Can Fam Physician. 2006;53(11):1403-1404.
  4. McGarry J, Daruwalla Z. The efficacy, accuracy and complications of corticosteroid injections if the knee joint. Knee Surg Sports Traumatol Arthosc. 2011;19:1649-1654.
  5. Sampson, S, Reed N, Silvers H, Meng M, Mandelbaum B. Injection of platelet-rich plasma in patients with primary and secondary knee osteoarthritis: a pilot study. Am J Phys Med Rehabil. 2010;89(12):961-969.