Osteoarthritis (OA) is a major cause of musculoskeletal (MSK) pain that affects more than 10% of Canadians over the age of 15 [1, 2].
It is a degenerative disease of the whole joint, including the cartilage and underlying bone, ligaments, and the capsule surrounding the joints.
The cartilage, or protective layer on the ends of your bones, breaks down leading to significant pain and loss of function.
While OA is most commonly found in the hips, knees, spine, hands, and big toes, this article will focus on OA of the knee.
Who develops OA and what does it look like?
Current research supports the theory that OA develops through a combination of traumatic injury, changes in the mechanical function and alignment of the bones, and chronic inflammation [4,5].
Individuals who have experienced a previous joint injury, such as an anterior cruciate ligament injury, or who are older, or are overweight, are at increased risk of developing OA.
Typical symptoms include pain in the affected joint, stiffness in the joint the morning, loss of joint range of motion, and swelling. As OA progresses there are other changes that can be seen on x-ray such as loss of space between the femur and tibia, thickening of the bone surface, formation of cystic (fluid-filled) lesions, and bone spurs, as shown in the image below .
How is OA diagnosed?
OA can be diagnosed by your doctor based on your description of your symptoms, along with a physical examination of your affected knee.
To assess your knee function, your doctor will observe you stand and walk, assess the range of motion in the knee, and perform specific physical examination tests to check ligament function.
Sometimes your doctor will order an x-ray to better understand the extent of cartilage loss in the joint. However, there is not always a direct relationship between the severity of your symptoms and the results of the x-ray.
Therefore, it is important that you and your doctor discuss a treatment plan that is based on your symptoms and level of function.
Unfortunately, there is currently no cure for OA, but there are measures that you can take to reduce joint pain and increase your quality of life.
How can I manage OA?
The first step in OA management is staying active!
Regular activity will improve pain, decrease joint stiffness, and improve overall function [7, 8].
There is no specific exercise routine that has been proven to be most effective, but studies have shown that it is important to participate in an activity that you enjoy, are motivated to do regularly, and have easy access to .
Anticipate experiencing some pain and swelling in your joint following exercise; this does not mean that you are damaging the joint further .
You may need to adjust your routine to account for recovery time between more aggressive activities. If you are experiencing joint pain the day after activity, you may have done too much the day before and could consider lowering the intensity or duration of exercise next time.
Staying active is key to managing a chronic disease like OA and will allow you to take control of your day-to-day function .
Weight loss is often recommended as a treatment for knee OA.
This is because studies have shown that individuals with a higher body mass index (BMI) experience larger forces in their joints . As a result, they develop more severe OA, decreased mobility, and higher rates of joint replacement [12, 13].
Research has shown that patients with OA who lose 10-20% of their body weight can have dramatically improved pain, function, and quality of life .
For this reason, if your doctor recommends weight loss, a good starting goal is 5% of your body weight.
We understand that trying to lose weight while your knee is painful and swollen can be difficult. A dietician referral may be a helpful first step.
Another effective management strategy for knee OA is physiotherapy.
Research has demonstrated that physiotherapy can improve proprioception (sensing where your joint is in space), agility, and balance .
Targeted exercises can also help to strengthen the muscles surrounding the knee joint, in addition to your core, hip and ankle joints, to improve joint mechanics and function .
Doing aquatic physiotherapy or pool-based exercises has also been shown to be very effective for improving strength and function .
Bracing the affected knee is another option you may consider so that you can continue to lead an active lifestyle .
A common type of brace used for OA is an unloader or offloader brace which helps to reduce load on the cartilage-worn side of the joint, which re-establishes joint space.
It takes some time to get used to wearing these braces so you may need to slowly build up the time you spend wearing the brace over a few weeks.
These braces are best fitted by a qualified orthotist and your doctor can give you a referral if your knee is likely to benefit from this type of brace.
Depending on the severity of your symptoms, you may consider medication therapy in conjunction with the treatments discussed above.
Topical anti-inflammatory gels such as diclofenac can be applied to the painful joint as needed and are a good first option before starting oral medication .
If topical pain relievers are not effective, you can progress to oral medications such as acetaminophen (Tylenol) or NSAIDs (non-steroidal anti-inflammatory drugs).
Acetaminophen is considered first line treatment for OA pain as it has no drug interactions or common contraindications [9, 16, 19]. Acetaminophen reduces pain while NSAIDs reduce both pain and swelling.
However, regular NSAID use can lead to increased risk of gastrointestinal issues such as ulcers and irritation of the stomach and intestines. For these reasons it is important to carefully review the safest way to take your medications with your doctor and pharmacist.
Prescription narcotics or opioid medications such as morphine or hydromorphone are not recommended for OA .
There are many supplements which claim to be beneficial for OA, however, none of these have strong evidence to demonstrate that they are safe and effective.
Before initiating any medication or supplement, you should discuss these treatments with your doctor and/or pharmacist as they can interact with other medications and cause side-effects.
Another type of treatment for the symptoms of knee OA is joint injections [19, 20].
While there are many types of joint injections, three that are commonly used are cortisone, hyaluronic acid, and platelet-rich-plasma (PRP).
Cortisone is a steroid hormone and can be injected into the knee to decrease inflammation and provide short term, moderate pain relief .
Hyaluronic acid is a sugar molecule found naturally in cartilage that primarily helps to lubricate the joint. Hyaluronic injections have been shown to be beneficial for pain relief in the intermediate term and can improve knee function .
PRP injections involve taking platelets from your own blood and injecting them into the affected joint to accelerate healing. Recent evidence has demonstrated that PRP injection “has the potential to provide improvements in pain and functional outcomes up to one year after the injection in patients with mild to moderate knee OA” .
Injections can be a very effective tool in managing pain, keeping you active, and delaying the need for surgery.
In severe cases of OA, where non-surgical treatment options have failed, it may be time to consider a consultation with an orthopedic surgeon.
In patients where OA affects one side of the knee more than the other, a high tibial osteotomy (HTO) can be performed.
HTO is a procedure which off-loads the side of the knee with OA to help preserve the remaining cartilage . It is a good option for improving pain and increasing function in patients who are active and reasonably fit.
A partial knee replacement may also be done for patients with lower demands on their knees, and who have intact knee ligaments, healthy cartilage in the other compartment, and sufficient knee range of motion .
However, if OA affects the entire knee joint, and there is significant loss of function in addition to pain, a total joint replacement should be considered.
Recovery time for each of these surgeries varies, but you should anticipate recovery taking 9-12 months before you are able to do most activities again. Your surgeon will discuss the options available with you, including the risks and benefits of each procedure, during your initial consultation.
Brodie Ritchie, MSc, MD Candidate, University of Alberta
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