Knee Osteoarthritis | A Physio Explains Everything You Need To Know About It

Written By on January 17, 2022 — Medically Reviewed By Kris Ceniza (PT)

Written by on January 17, 2022 — Medically Reviewed By: Kris Ceniza (PT)

Research shows that knee osteoarthritis affects 16% of the population worldwide. And, contrary to popular belief, it doesn’t only affect the elderly. (1)

Almost 23% of people between 15 and 40 years old have some degree of knee osteoarthritis. And some of them have no symptoms at all. (1, 2)

Sadly, this degenerative process can’t be reversed. But, if you do have symptoms, there are several treatments available to manage them. You may even avoid surgery if you act early enough.

This article will give you an up-to-date overview of knee osteoarthritis. Here are the topics I will cover:

Tap on any of the questions above to go straight to the answer. Or, keep reading and start with the basics:

What is osteoarthritis in the knee joint?

Knee osteoarthritis is a degenerative process where the joint surfaces of the knee are worn out and torn.

See, most of our joints are lined with articular cartilage. This is a smooth tissue that lets our bones glide over each other without much friction.

But, after years of using our joints, this cartilage wears off. This degeneration is particularly common in weight-bearing joints, like the knee.

This is also why osteoarthritis is considered a progressive disease.

Because the more we put our joints through excessive stress, the worse it gets.

In advanced stages, the cartilage damage can be so severe that there won’t be much joint space left. It may also affect the other knee, causing bilateral osteoarthritis.

Knee Force Knee Sleeve

Learn more: The 4 stages of osteoarthritis and their symptoms

What causes knee OA?

The main cause of knee osteoarthritis is overuse. The repetitive stress on the knee leads to joint cartilage loss. This type of OA is known as “primary knee osteoarthritis.”

Yet, some lifestyle factors and injuries can make you prone to knee osteoarthritis. This is also called “secondary knee osteoarthritis.”

Risk factors of knee osteoarthritis

People prone to develop osteoarthritis in the knee joint include (1, 3):

  • Women
  • People over 65 years old
  • People with a BMI >25
  • Athletes involved in running sports, weight lifters, and wrestlers
  • Having a previous meniscus tear and/or ACL tear

Further reading: Causes of knee osteoarthritis

How is knee osteoarthritis diagnosed?

Four knee joints show the radiographic progression of osteoarthritis, from mild to severe.

To diagnose knee osteoarthritis, your doctor will do a physical exam first. He/she will request a magnetic resonance imaging (MRI) of your knee joint and maybe some blood tests, too.

That will help them rule out other diseases to provide an accurate diagnosis.

Now, for your doctor to give you a proper knee osteoarthritis diagnosis, there’s some criteria you have to meet. It includes (2, 4, 5):

  • Being >50 years old
  • During the physical exam – Having knee tenderness, knee noises, normal skin temperature
  • In your daily life – Feeling knee stiffness for <30 minutes, some level of pain
  • In your MRI – Presence of bone spurs, cartilage defects, meniscal tears, lack of joint space
  • In your blood tests – No signs of an autoimmune disease, healthy synovial joint fluid

Go deeper: How a knee OA diagnosis is made?

Wait, what’s the difference between knee osteoarthritis and rheumatoid arthritis?

First, both are two types of knee arthritis. This term means “knee joint swelling.”

Now, knee osteoarthritis is the most common form of knee arthritis. As stated above, the main cause is overuse. (5)

But, rheumatoid arthritis is one of many musculoskeletal and skin diseases caused by a dysfunction of the immune system. It causes swelling in the joints of the hands and fingers.

Although both conditions cause knee arthritis, the treatments are completely different. That’s why your doctor may request blood tests so he/she can accurately identify the type of arthritis affecting you.

Symptoms of knee joint OA

Front view of a person standing with a "bow leg" deformity on their left leg - a symptom of osteoarthritis in the knee

People with symptomatic knee osteoarthritis have a wide variety of symptoms, including (4):

  • Joint pain, ranging from mild to incapacitating
  • Joint stiffness, mostly in the morning
  • Swelling of varying degrees
  • Instability, as if the knee gives away under you
  • Cracking, grinding, and other joint noises
  • Visual deformity of the knee in advanced cases

At first, you may feel pain with weight-bearing activities, like standing, walking, or climbing stairs.

But, as the degeneration progresses, the pain in the affected joint may be present at rest, too. It can make it hard for you to lay down or sleep.

Related: The 10 symptoms of knee OA + treatments

Treatment of knee pain from osteoarthritis

Although knee osteoarthritis can’t be reversed, some treatments can slow down the progression of the condition if you do them soon enough. While other treatments will help you manage the symptoms when they’re severe.

The top 8 treatments for knee osteoarthritis are:

1) Self-Management/Home treatments

Most medical societies say: Strongly recommended

Knee Force Knee Sleeve

And we agree. Home management is the best treatment for knee osteoarthritis! (6, 7)

The healthcare professionals handling your case will teach you how to manage your condition at home. Here’s what you should expect to learn from them (6):

  • Home treatments for knee osteoarthritis
  • What to do when the pain gets worse
  • How to protect your knee while exercising
  • How to comply with your medication
  • Stress management techniques
  • Problem-solving scenarios

The goal of educating you in these aspects is so you can navigate through your daily life more confidently. You’ll be able to reduce pain, knee stiffness, and joint swelling on your own.

You’ll love this: 11 home treatments for osteoarthritis knee pain that actually work + instructions

2) Exercise

Two people doing tai chi, a great exercise for treating knee OA

Most medical societies say: Strongly recommended

Exercise has shown time and time again how beneficial it is for knee osteoarthritis. It strengthens your knee joint muscles, keeps your articular cartilage healthy, and can reduce arthritis pain. (6, 7)

And, the best thing is that it doesn’t matter what exercise you do. You just have to enjoy doing it because it helps with your adherence.

But you may feel some increase in knee pain or muscle soreness at first. This is expected, mostly if you’re not used to exercising at all. (6)

Don’t worry. Your physical therapist will have recommendations ready if (and when) this happens.

3) Medication

Most medical societies say: Strongly recommended

Several over-the-counter medications can provide pain relief and improve your quality of life. (6, 7)

Topical or oral anti-inflammatory drugs (NSAIDs) can help relieve pain and reduce swelling. Both are effective, so discuss with your doctor which format suits you the best. (6)

Acetaminophen also helps with pain, but it’s not as effective for reducing inflammation. At least when compared to NSAIDs. (6)

What medication is best for osteoarthritis?

Your doctor will be the best person to answer that as there’s really no concrete response. She/he will take into account your medical history before recommending any medication.

Learn more: 11 Types of medication for knee OA (evidence-based guide).

4) Wearing knee supports

A person walking while wearing a knee support to manage knee OA symptoms

Most medical societies say: Recommended

The right knee brace provides incredible benefits. It can reduce your pain, protect your joint from further injury, and increase your confidence while doing your daily activities. (6)

If that wasn’t enough, this is one of the treatments with the least amount of side effects. If any, the brace might only feel uncomfortable or cause rashes to sensitive skin. (6)

Plus, you can easily prevent these issues by checking the fabric blend of the brace and making sure you wear the right size.

The best part is that there’s a nearly infinite variety of knee braces that can help with your symptoms, whether they be mild or severe.

This will help: What type of knee brace you will need

5) Lose weight

Most medical societies say: Recommended

Patients with a BMI >25 will likely have less pain and better knee function if they lose weight. (6, 7)

Ideally, this weight loss intervention would be done gradually, under medical supervision, and with a combination of dietary and exercise strategies.

Note: Losing weight and keeping it off is hard. So, a less frustrating approach may be aiming at reducing body weight by 10%. This is enough to provide benefits for most patients with BMI>25 and knee OA. (6)

6) Dietary supplements

Most medical societies say: Can help in mild/moderate osteoarthritis

These are some of the supplements that may help reduce pain in the first stages of knee osteoarthritis (6):

There’s not much research available regarding which supplement is best and for whom. But, they won’t cause harm to healthy people who don’t exceed the dose the manufacturer suggests. (6)

Talk with your doctor before taking any supplement, especially if you also take medications or have any other health condition.

You’ll like this: Our top 9 supplements for knee OA

7) Intra-articular injections

Two anatomical views of a knee joint to show the different places of intra-articular injections

Most medical societies say: It depends

This treatment consists of injecting a compound into the arthritic knee to help relieve symptoms. The most popular are (6):

  • Hyaluronic acid – can help some people but after the treatments above have failed
  • Platelet-rich plasma – similar to hyaluronic acid
  • Intra-articular corticosteroids – provide short-term relief but may accelerate osteoarthritis

Please, keep in mind that injecting your knee is a personal decision. Your healthcare team should discuss it with you first. Make sure to ask about the pros and cons, potential outcomes, and risks.

Related: Nonsurgical treatments for knee OA for short and long-term relief.

8) Surgical treatment

Comparison of two knee joints, one with severe knee osteoarthritis and another with a total knee replacement

Most medical societies say: It depends

As with injections, undergoing surgical treatment is a very personal decision.

Most orthopaedic surgeons recommend it when symptoms severely limit your daily life and/or the treatments above have failed. (8)

Now, there are several types of knee surgeries for osteoarthritis.

The most known is joint replacement surgery. Here, the surgeon replaces the part of the joint that’s damaged with an artificial alternative. In severe cases, they may have to replace the whole joint.

Another option is removing the bone spurs if they are causing symptoms. This is usually done through arthroscopy. (8)

Young and/or active patients often undergo a knee osteotomy. Here, the goal is to take the pressure off the damaged cartilage. (8)

There are some things to consider before undergoing knee OA surgery. But, if you decide to do it, make sure to talk with your physician about the procedure.

Ask them about the pros, cons, if there are other options available, and any other thing that will bring you peace of mind.

Further reading: When is surgery necessary for osteoarthritis in the knee?

But, what is the best treatment for YOU?

If you’ve been diagnosed with knee osteoarthritis, the best thing to do is go to a physical therapist first.

Your physio will work in tandem with your doctor and other healthcare professionals to give you the best care possible. This may look like:

  • Teaching you self-management
  • Treating your symptoms in the clinic with active and passive strategies
  • Designing an exercise program for your needs
  • Helping you prepare for knee surgery

We – physical therapists – are specifically trained to help you recover from painful conditions, like knee OA. We work with you to get you as close as possible to your previous lifestyle.

Learn more: Ranking of treatments for knee osteoarthritis – from best to worst


What does osteoarthritis in the knee feel like?

Symptoms vary from person to person. You may feel a dull, deep pain inside the joint. Swelling and instability may be present or not. Your knee may crack or grind as well.

Yet, these symptoms can also be present in pretty much any other knee injury. So, if you think you have knee osteoarthritis, please visit your doctor to get an accurate diagnosis.

Can you heal knee osteoarthritis?

No, knee osteoarthritis is irreversible. But, several treatments can manage the symptoms and slow down the progression of the disease.

How serious is osteoarthritis (OA) of the knee?

The severity is a case-by-case scenario.
For example, some people with OA may have a severely damaged cartilage but can live their lives pain-free. Others will have incapacitating symptoms that may require surgery to improve.

Conclusion: What is osteoarthritis of the knee?

Knee osteoarthritis is the wear and tear of the articular cartilage in this joint.

This degenerative process is irreversible. But, several treatments can relieve pain, improve your daily life, and even delay surgery.

Finally, if you’re not sure what to do, go to physical therapy. Your therapist is trained to guide you through this process!


  1. Cui, Aiyong et al. “Global, regional prevalence, incidence and risk factors of knee osteoarthritis in population-based studies.” EClinicalMedicine published by The Lancet vol. 29-30 100587. 26 Nov. 2020, DOI: 10.1016/j.eclinm.2020.100587
  2. Culvenor, Adam G et al. “Prevalence of knee osteoarthritis features on magnetic resonance imaging in asymptomatic uninjured adults: a systematic review and meta-analysis.” British journal of sports medicine vol. 53,20 (2019): 1268-1278. DOI: 10.1136/bjsports-2018-099257
  3. Driban, Jeffrey B et al. “Is Participation in Certain Sports Associated With Knee Osteoarthritis? A Systematic Review.” Journal of athletic training vol. 52,6 (2017): 497-506. doi:10.4085/1062-6050-50.2.08
  4. Alshami, Ali M. “Knee osteoarthritis related pain: a narrative review of diagnosis and treatment.” International journal of health sciences vol. 8,1 (2014): 85-104. DOI: 10.12816/0006075
  5. Hsu H, Siwiec RM. “Knee Osteoarthritis.” [Updated 2021 Jul 25]. Statpearls. Retrieved on December 2021 from:
  6. American Academy of Orthopaedic Surgeons Management of Osteoarthritis of the Knee (Non-Arthroplasty) Evidence-Based Clinical Practice Guideline (3rd Edition). Published August 31, 2021.
  7. Bannuru, R R et al. “OARSI guidelines for the non-surgical management of knee, hip, and polyarticular osteoarthritis.” Osteoarthritis and cartilage vol. 27,11 (2019): 1578-1589. DOI: 10.1016/j.joca.2019.06.011
  8. Luthra JS, AL Habsi S, AL Ghannami S (2020) Surgical Options for Treating Knee Osteoarthritis – A Concise Review. J Musculoskelet Disord Treat 6:084.
Mitch Torres (PT)
Mitch is a physical therapist, personal trainer, and nutrition coach. Fascinated with the knee joint, Mitch poured that passion into writing about knee pain and how to overcome it with movement. His goal is to teach you how to apply this knowledge into your daily life, so you can keep knee pain away for good.