Doctors need to do 3 things to make the diagnosis of knee osteoarthritis – know your medical history, perform a physical examination, and request imaging tests. (1)
Some people may have to do some type of laboratory testing, too. This is to rule out other conditions that require a different treatment plan. (1)
And as tiresome as it may look, this diagnostic process is critical. It gives all the information needed to provide the right treatment.
Below, we’ll walk you through each step to diagnose osteoarthritis of the knee. Here’s what you’ll learn, tap on any topic to go to its section:
- Medical history (symptoms and risk factors)
- Physical examination
- Imaging tests (X-rays and MRIs)
- Laboratory testing (blood and joint fluid tests)
- Conditions to rule out before diagnosing knee OA
- What happens after the diagnosis?
The 4 steps of a knee osteoarthritis diagnosis
Your doctor will combine the findings of each step to get a diagnosis. The first one is:
1) Knowing your medical history
Here, you’ll talk with your doctor about your symptoms, your personal and family history, and what your daily life looks like.
Apart from the site of the knee pain, make sure to tell your doctor (2):
- What alleviates your symptoms?
- What makes them worse?
- Does it radiate to other areas?
- Is there a moment of the day when they’re better/worse?
- Which activities are the most affected by your symptoms?
This will give your doctor a good idea of what’s going on with your knee joint.
Now, if these symptoms and risk factors are present, your doctor might suspect you have knee osteoarthritis:
Common symptoms of knee osteoarthritis
Although the main symptom is knee pain, these characteristics may point at osteoarthritis as the cause (2, 3):
- The pain worsens with movement. Like walking, squatting, or climbing stairs.
- Rest can be a double-edged sword – it may soothe and/or aggravate the pain.
- In severe cases, the pain is so intense it wakes you up at night.
Other knee osteoarthritis symptoms include (2, 3):
- Joint stiffness that lasts 30 minutes or less.
- A grating sensation when you bend and/or straighten your knee.
- Lack of range of motion in your knee joint.
- Mild swelling.
- Impairment in your daily living.
For mild to moderate cases, these symptoms tend to get better with home treatments. Like NSAIDs, ice/heat therapy, or wearing a knee brace.
Related: 10 Symptoms of knee osteoarthritis
Several health and lifestyle factors can predispose you to knee osteoarthritis, such as (2, 4):
- Being over 60 years old. This is a major risk factor.
- Having a previous knee injury, like a meniscus or ligament tear.
- Being overweight or obese.
- Frequent squatting due to your occupation or hobbies.
- Being of the female sex.
- Having a genetic predisposition.
If you have some of the symptoms mentioned above and any of these risk factors, your likelihood of having knee OA will increase. (3)
Related: The 2 Major Causes of Knee Osteoarthritis
2) Doing a physical exam
In this second step, your doctor will inspect your knee joint. Here are common things most physicians do during a physical exam (1, 2):
- Palpate your affected joint to check for tenderness, redness, and specific pain points.
- Move your joint to assess your range of motion.
- Perform specific maneuvers to see if your ligaments, meniscus, and/or kneecap are affected.
- Assess your walking pattern.
- Request specific movements, depending on what was previously discussed.
After this exam, your orthopaedic doctor will likely have a good idea of what’s happening with your knee.
But, to make an accurate knee osteoarthritis diagnosis, he/she will need to see if there’s any damage in your joint. And if so, how severe it is.
Thus, the next step is:
3) Requesting knee joint imaging tests
This third step will show the state of your knee joint from the inside. Depending on the physical examination, your doctor will request one or both of these tests:
Note: Doctors can’t make a knee osteoarthritis diagnosis out of imaging tests alone. To make an accurate diagnosis, your doctor must use this as a tool to complement the information from the steps above. (3)
This is a quick way to see the inside of your knee bones and how close they are to each other.
Now, if your X-rays show any of the following, there’s a high probability of having knee osteoarthritis (2, 3):
- Bone spurs.
- Joint space narrowing.
- Thickening of the bone (subchondral sclerosis).
- Tiny cysts inside the bone (subchondral cysts).
Magnetic resonance imaging (MRI)
This other test shows the state of soft tissues – your ligaments, meniscus, muscles…
Your doctor may request an MRI if she/he suspects you have a meniscus or ligament tear, for example. This can be the case if you also feel like your knee is unstable, or if it gets locked frequently.
4) Requesting laboratory tests
For most people, this step is unnecessary for diagnosing knee osteoarthritis.
However, your doctor may need to rule out any other musculoskeletal and skin diseases. Like rheumatoid arthritis, bursitis, arthritic psoriasis, or gout.
This is because some conditions have similar symptoms or can happen at the same time as knee OA. Their presence will change and/or affect your treatment plan.
The most common laboratory tests are (3):
- Blood tests.
- Urine tests.
- Synovial fluid analysis.
Conditions to rule out before making a knee OA diagnosis
The following conditions can cause symptoms similar to osteoarthritis of the knee: (2, 3)
- Rheumatoid arthritis.
- Meniscus tear.
- Ligament sprain.
- Patellofemoral pain syndrome.
- Iliotibial band syndrome.
- Knee bursitis.
- Septic arthritis.
- Spine problems.
What happens after diagnosing knee osteoarthritis?
The next step is figuring out a treatment plan to relieve osteoarthritis symptoms. The specifics of your treatment will depend on your lifestyle, age, symptoms, and goals.
Yet, it’s important to know these remedies won’t repair the joint damage. They can delay the process of cartilage loss, though.
Most treatments for knee osteoarthritis include:
Osteoarthritis is a chronic condition. As such, learning how to manage it will help you keep your quality of life.
These strategies include treatments for short and long-term relief, such as (2, 3):
- Heat/cold therapy.
- Nonsteroidal anti-inflammatory drugs (NSAIDS).
- Exercise – strengthening and/or aerobic training.
- Wearing knee braces for osteoarthritis.
- Transcutaneous electrical nerve stimulation (TENS)
- Weight loss for people with a BMI >30.
- Dietary supplements, like glucosamine and chondroitin.
Related: 11 home remedies for knee OA that actually work
Your doctor will likely recommend going to physical therapy. Some people might need occupational therapy as well.
These healthcare professionals will help you manage your chronic pain. Also, they will teach you individual strategies to keep your osteoarthritis pain at bay.
These can reduce pain and provide short-term relief. They provide even better results if paired with physiotherapy and self-care strategies.
The most common are hyaluronic acid and corticosteroid injections. Each one has its pros and cons, so make sure to discuss this with your doctor before undergoing this treatment.
Related: 10 evidence-based treatment options for knee OA
This is the best option for people with severe knee osteoarthritis. Or, for people with a deteriorated lifestyle due to this condition.
There are several surgical options available. The best for you will depend on your symptoms, age, lifestyle, and what your surgeon considers ideal for your case. They include:
Regardless of the surgical treatment, you’ll need physical therapy afterward. This will make sure you recover fully while preventing future complications.
Related: When is surgery necessary for knee osteoarthritis?
How do you diagnose knee osteoarthritis?
Your doctor will take your medical history, perform a physical exam, and request imaging tests. If needed, you may need laboratory tests too to rule out other conditions.
How do you test for knee osteoarthritis?
There isn’t a specific test for knee osteoarthritis, yet. To diagnose this condition, your doctor has to combine the findings of your:
– Medical history,
– Physical exam,
– X-rays and/or MRI,
– And laboratory tests.
How do I know if I have knee osteoarthritis?
If you’re 45 years old and have these 6 elements at the same time, there’s a 99% chance you have knee osteoarthritis (3):
– Knee joint pain that worsened over time,
– Morning joint stiffness for 30 minutes or less,
– A grating sensation while bending/extending,
– Limited range of motion,
– Deterioration of your quality of life due to knee pain,
– And x-rays showing bone spurs on your knee joint.
Conclusion: Knee osteoarthritis diagnostic process
Osteoarthritis is a common disease of weight-bearing joints. That’s why hip and knee osteoarthritis are so typical.
And, even though it’s tempting, having a radiographic knee OA can’t be the ONLY diagnostic criteria. It won’t make for an accurate diagnosis.
So, try going to an orthopaedic doctor that makes a thorough assessment. This will rule out other conditions and make sure you get the right treatment.
- Michael, Joern W-P et al. “The epidemiology, etiology, diagnosis, and treatment of osteoarthritis of the knee.” Deutsches Arzteblatt international vol. 107, 9 (2010): 152-62. DOI: 10.3238/arztebl.2010.0152
- Hsu H, Siwiec R M. Knee Osteoarthritis. [Updated 2021 Jul 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK507884/
- Zhang, W et al. “EULAR evidence-based recommendations for the diagnosis of knee osteoarthritis.” Annals of the rheumatic diseases vol. 69, 3 (2010): 483-9. DOI: 10.1136/ard.2009.113100
- Jang, Sunhee et al. “Recent Updates of Diagnosis, Pathophysiology, and Treatment on Osteoarthritis of the Knee.” International journal of molecular sciences vol. 22, 5 2619. 5 Mar. 2021, DOI: 10.3390/ijms22052619
- Heidari, Behzad. “Knee osteoarthritis diagnosis, treatment and associated factors of progression: part II.” Caspian journal of internal medicine vol. 2,3 (2011): 249-55.