A Pain Management Physician’s Approach to Knee Pain Treatment
Knee pain is one of the most common reasons patients come into the doctor’s office. Frequent knee pain affects almost 25% of adults and causes limitation in mobility and function along with reduced quality of life. Osteoarthritis is the most common cause of knee pain in people over 50 years old with 37% of those 60 years and older having it confirmed with radiographic evidence (e.g., by x-ray). Women are more often affected than men. Untreated knee pain can lead to severe chronic pain that is difficult to manage and treat. Osteoarthritis of the knee causes pain, stiffness, reduced joint motion and muscle weakness. These limitations reduce functionality and quality of life. In this post, general treatment options will be discussed from a pain management physician’s perspective.
Tissue Injury with Knee Pain
The most common form of knee pain is from osteoarthritis driven by nociceptive or tissue injury to the structures in the knee. Pain is due to the loss of cartilage in the knee resulting in constant tissue injury to the bone and other structures in the knee. The tissue injury in the knee triggers an inflammatory cascade that results in degeneration of the remaining cartilage and bone and starts a vicious cycle of injury then pain and then further injury and pain until there is no cartilage left and bone is touching bone. Any tissue injury in the knee can result in pain and if left untreated can lead to severe nerve pain as well which becomes difficult to treat and therefore it is important to get treatment for knee pain as soon as it starts.
Risk Factors for Knee Osteoarthritis
- The following are the most common risk factors of knee osteoarthritis.
- Older age
- Female sex
- Overweight or obese
- Previous knee injury
- Occupational factors (excessive heavy lifting, knee bending, squatting, etc…)
- Varus or Valgus alignment (i.e., structural misalignments in the knee such as bow-leg)
Treatment Options for Knee Pain
The most important part of treating knee pain is tailoring the treatment plan to your unique needs. In most instances of knee pain, it is important to maintain physical activity including exercises to strengthen the surrounding muscles. Tai chi and aerobic exercises with lower impact on the knee joints can also be very helpful in promoting good balance and improved functional outcomes such as ability to walk. Weight management is also important since higher BMI (body mass index) is also associated with increased knee pain and poor outcomes from traditional treatments. Physical therapy is the foundation of treatment for any form of knee pain. It is almost always helpful to see a physical therapist after your doctor says you can safely engage in stretching and resistance training.
For many patients, the initial treatment for knee pain after the injury or pain starts is to rest and apply ice if there is swelling in the knee. However, if the pain does not subside within a few days it is important to see your doctor for further treatment recommendations and for most patients I would recommend using topical NSAID (i.e., non-steroidal anti-inflammatory) gel that can suppress the inflammatory response around the knee. While this was only available as a prescription in the past, it is now readily available over the counter at any drug store (e.g., Voltaren®). If this is not effective then medications like ibuprofen (e.g., Advil®) and naproxen (e.g., Aleve®) are appropriate to improve the pain. There are also stronger prescription NSAID medications that can be prescribed by your doctor if needed. Acetaminophen (e.g., Tylenol®) is also a useful medication to add in with any NSAID medication but care should be taken not to take too much as it is metabolized by the liver and taking too much of it can be toxic and lead to liver failure. Opioid medications conversely have no role in long term management of knee pain.
Non-Invasive Nerve Stimulation
A unique category of treatment is non-invasive stimulation with transcutaneous electrical nerve stimulation (TENS) unit which can treat both acute and chronic knee pain. There are numerous TENS units on the market for you to choose from, including several that are specifically designed for knee pain such as the Quell® device*. When used consistently, TENS can modulate and decrease pain levels and improve functionality as measured by increased ability to walk.
If the knee pain does not improve with the less invasive treatments or the pain is very severe and debilitating then a knee injection of glucocorticoid (referred to as a “steroid”) can help provide a strong local anti-inflammatory medication into the knee joint to help suppress the pain and allow improved range of motion in the joint. If these steroid injections are helpful and there is evidence for osteoarthritis in the knee based on clinical exam and x-rays then hyaluronic acid injections (commonly referred to as “gel shots”) in the knee joints can also provide pain relief for patients with mild to moderate osteoarthritis.
Nerve Blocks and Radiofrequency Ablation
If the knee pain has been ongoing for several months or resistant to many other treatments then it is time to consider nerve blocks and radiofrequency ablation to help manage the pain. The genicular nerves provide the sensory information from the knee joint to the brain. Performing a nerve block to these nerves can block the pain signal temporarily from the knee to the brain. While helpful these nerve blocks generally last anywhere from a few days to a few weeks. Radiofrequency ablation of the genicular nerves involves providing a high temperature energy to these nerves to stop their signal from being delivered to the brain. This treatment provides around a year of pain relief in the knee.
Less studied treatments like CBD, acupuncture and peripheral nerve stimulation can also be helpful for severe hard to treat knee pain. More research is also being done on the role of platelet rich plasma or PRP injections and their role in helping with knee pain. I often advocate trying these treatments after a through discussion. However, as always, the treatment plan must be personalized for your needs and goals.
When all other treatments have failed and there is evidence of severe tissue injury to the knee joint, then it is time to consider a knee replacement. This requires consultation with a specialized orthopedic surgeon that performs many knee replacements a year to make sure you get the most personalized approach for your surgery.
The most important goal when treating knee pain is to make sure there is significant reduction in pain around the knee to help improve functional outcomes like walking. Often treatment needs to have a multimodal approach encompassing many different options including physical therapy, non-invasive and more interventional treatments.
*Quell is intended to treat lower extremity chronic pain such as knee pain. It has not been reviewed or cleared by the Food and Drug Administration (FDA) for specific medical conditions such as osteoarthritis.
The Content in this post is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read in this post.
NeuroMetrix compensated Dr. Maddalo to share his perspectives on knee pain. The thoughts and opinions in this blog post are his own.
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