The Knee - Osteoarthritis

Before a needle or the knife, try some exercise. It's best practice.

Knee osteoarthritis, or knee OA, is one of the most prevalent and debilitating chronic degenerative joint diseases, affecting up to 30% of people aged over 50, with a hallmark symptom of pain. This in turn can affect balance, with a concomitant increase in the risk of falls and associated injuries.

In Australia we have comprehensive guidelines based on research helping us to know how to assess and manage this condition. These guidelines support a non-surgical approach as first-line management for knee OA, with strong evidence for exercise coupled with appropriate pain relief and targeted physiotherapy. Check out this fact sheet for more information about knee OA.

A little bit of anatomy

The knee is made up of two main joints – the tibiofemoral joint between the shin bone (tibia) and the thigh bone (femur), and the patellofemoral joint between the kneecap (patella) and the femur. The ends of the bone are covered with articular cartilage which absorbs and distributes load and helps with smooth movement. There is another thicker cartilage between the thigh bone and shin bone called the meniscus which adds another layer of shock absorption and improves contact between the tibia and femur.

Osteoarthritis affects all the structures of the knee joint including the ligaments, nerves, and muscles, but mainly the articular cartilage.

Normally, there is a balance between the body making new cartilage to replace older cartilage. In osteoarthritis this balance is impacted which can affect the amount of healthy cartilage. Pain associated with knee OA arises from changes to surrounding tissues, particularly the synovial tissue, as well as articular cartilage. As tissues become tight and stiff, the biomechanics of the joint are altered, impacting the way load is distributed. Alterations to the thickness of articular cartilage further affect load absorption and distribution, resulting in further degenerative change. 

Who gets it?

Knee osteoarthritis is common in Australia, affecting 1.2 million people, with females impacted at slightly higher rates than males. About 70% of people with knee osteoarthritis are older than 55, however younger people can also be affected. Factors that contribute to an increased risk of developing osteoarthritis include a history of knee injuries, previous surgery, and being overweight. There may also be a link with overall health including blood pressure, diabetes and high cholesterol.

Obesity remains one of the most important risk factors for the incidence and progression of OA.

Obesity increases the risk of OA in both weight-bearing (knee) and non-weight-bearing (hand) joints and doubles the lifetime risk of symptomatic OA compared to individuals with a lower BMI. Recent studies have demonstrated that factors related to obesity – adipose deposition, insulin resistance, and altered immune responses – may lead to the initiation and progression of obesity-associated OA.

Diagnosing Knee OA

Symptoms common to knee OA include intermittent or constant knee pain that is gradual in onset and worsens with activity, joint stiffness, particularly first thing in the morning, crepitus or cracking with certain activities such as ascending stairs or squatting, and pain after prolonged sitting or resting. The most common symptom of pain arises due to changes in the synovial tissue, and redistribution of load away from the cartilage (which has minimal nerve supply and loves load) to the underlying bone which has a rich nerve supply and is not tolerate of these forces.

Signs of knee OA include joint swelling and redness, reduced knee joint range of motion, reduced balance, and joint line tenderness.

As there are many causes of knee pain it is important to see a qualified health professional to get a clear diagnosis. Your physiotherapist will listen carefully to you describe your symptoms and complete a thorough physical examination. A diagnosis of knee osteoarthritis is made if you have knee pain which is worse with activity, show signs and symptoms consistent with knee OA, and other causes of symptoms are ruled out.

Do I need a scan?

Scans are not recommended for diagnosing osteoarthritis. One of the reasons for this is what is seen on a scan does not normally match very well with a person’s symptoms, and generally will not change the recommended management.

In one study only 15% of patients with radiographic findings of OA had symptoms of OA.

A scan is only required if you have an atypical presentation, or if surgery might be indicated, which is a small percentage of people. Some people may require blood tests to rule out other conditions like rheumatoid arthritis. 

Treatment

Exercise is the number one treatment for osteoarthritis and is recommended in all international guidelines.

Exercise should be the first line of treatment for all patients. This could include specific strengthening exercises, a walking program, or hydrotherapy. Often when getting started with exercise pain can initially flare up, so working with a skilled physiotherapist is important to get the right balance.

Weight loss can be helpful if you are overweight. Research shows that losing even 2kg can significantly reduce levels of pain. Weight loss can be difficult and there are multiple factors involved in a person’s weight. Your physiotherapist can support you in planning if this is a priority for you.

Soft tissue therapy, manual therapy, pain medication, and/or joint injections are all options that can be tried if exercise is not having a large enough effect. These modalities can provide short term pain relief and improvements in function which can improve participation in therapeutic exercise. However, they are not a panacea, nor a replacement for exercise, and should not be pursued in isolation or for long periods of time.

Can I get an injection?

There are several injectable options available to persons with knee OA who have not progressed sufficiently with therapeutic exercise. It is important to recognize that injections are an invasive technique, and as such carry an increased risk profile for complications including infection. You can click on the links below for more information:

• Corticosteroid injections
• Hyaluronic acid (HA)
• Platelet-rich plasma (PRP)
• Stem cell therapy

Will I need surgery?

Most people with knee joint OA will not require surgery.  A small percentage of people will require joint replacement surgery. This is considered if the problem is not responding to other noninvasive treatments and is having a significant impact on quality of life. Arthroscopic surgery to “clean up” a knee joint with osteoarthritis has been shown to have no benefit.

Prior to considering surgery it is important that you have completed at least 3 months of a good quality exercise program. This is the minimum timeframe necessary to ascertain the benefits of a non-surgical approach and to improve strength and knee joint biomechanics. Failing this, your physiotherapist can provide guidance on available medical and surgical treatments, enabling you to make informed health care decisions. 

How long’s it going to take?

Currently there is no cure for osteoarthritis. OA needs to be managed over time with regular adjustments to lifestyle, daily living activities, and exercise type and quantity. Prognosis is positive for most people, and with a simple, progressive, therapeutic exercise program combined with lifestyle changes they can continue with good function.

Pain flare ups can occur and can be effectively managed with over the counter pain medication, soft tissue therapy, and adjustments to exercise programs. Research shows that people who continue with exercise programs over a long period tend to have less flare ups, improved functional capacity and better health-related quality of life. 

Take home Advice

Knee osteoarthritis is a common condition causing knee joint pain and stiffness. Your physiotherapist can make a diagnosis without any scans or blood tests. Guidelines recommend that the first line treatment for all people is exercise, and that this is highly effective in reducing pain and improving function under the guidance of a physiotherapist. 

Got knee pain and want to get it sorted? Give us a call.

At Movement for Life Physiotherapy, we can assess, diagnose, and treat your knee pain. We provide education and evidence-based advice coupled with a comprehensive treatment plan to help get you back to the things you love doing sooner.

Give us a call now or click on BOOK AN APPOINTMENT to book online.

References:

1. Australian Commission on Safety and Quality in Healthcare. (2024). Osteoarthritis of the Knee Clinical Care Standard. Retrieved October from https://www.safetyandquality.gov.au/standards/clinical-care-standards/osteoarthritis-knee-clinical-care-standard
2. Bannuru, R. R., Osani, M. C., Vaysbrot, E. E., et al. (2019, Nov). OARSI guidelines for the non-surgical management of knee, hip, and polyarticular osteoarthritis. Osteoarthritis Cartilage, 27(11), 1578-1589. https://doi.org/10.1016/j.joca.2019.06.011
3. Deyle GD, Allen CS, Allison SC, et al. Physical Therapy versus Glucocorticoid Injection for Osteoarthritis of the Knee. N Engl J Med. 2020;382(15):1420-1429. doi:10.1056/NEJMoa1905877
4. Henriksen M, Christensen R, Klokker L, et al. Evaluation of the benefit of corticosteroid injection before exercise therapy in patients with osteoarthritis of the knee: a randomized clinical trial. JAMA Intern Med. 2015;175(6):923-930. doi:10.1001/jamainternmed.2015.0461
5. Hsu H, Siwiec RM. Knee Osteoarthritis.2019 Available from: https://www.ncbi.nlm.nih.gov/books/NBK507884/ 
6. Kolasinski, S. L., Neogi, T., Hochberg, et al. (2020, Feb). 2019 American College of Rheumatology/Arthritis Foundation Guideline for the Management of Osteoarthritis of the Hand, Hip, and Knee. Arthritis Care and Research, 72(2), 149-162. https://doi.org/10.1002/acr.24131
7. Kon, E., Filardo, G., Drobnic, M., et al. (2012). Non-surgical management of early knee osteoarthritis. Knee Surgery, Sports Traumatology, Arthroscopy, 20, 436-449.
8. Michael JW, Schlüter-Brust KU, Eysel P. The epidemiology, etiology, diagnosis, and treatment of osteoarthritis of the knee. Deutsches Arzteblatt International. 2010 Mar;107(9):152.
9. Migliorini F, Driessen A, Quack V, et al. Comparison between intra-articular infiltrations of placebo, steroids, hyaluronic and PRP for knee osteoarthritis: a Bayesian network meta-analysis. Arch Orthop Trauma Surg. 2021;141(9):1473-1490. doi:10.1007/s00402-020-03551-y
10. Moretti L, Maccagnano G, Coviello M, et al. Platelet Rich Plasma Injections for Knee Osteoarthritis Treatment: A Prospective Clinical Study. J Clin Med. 2022;11(9):2640. Published 2022 May 8. doi:10.3390/jcm11092640
11. Nedunchezhiyan, U., Varughese, I., Sun, A. R., et al. (2022). Obesity, inflammation, and immune system in osteoarthritis. Frontiers in immunology, 13, 907750.
12. Ross, A., Gascon, G. M., Snow, R., et al. (2020). Outcomes of a conservative care program for knee osteoarthritis through translation of research into practice. Musculoskeletal Care, 18(3), 342-351.
13. Tong, B., Chen, H., Wang, et al. (2024). Clinical prediction models for knee pain in patients with knee osteoarthritis: a systematic review. Skeletal Radiology, 53(6), 1045-1059.
14. Wei P, Bao R. Intra-Articular Mesenchymal Stem Cell Injection for Knee Osteoarthritis: Mechanisms and Clinical Evidence. Int J Mol Sci. 2022;24(1):59. Published 2022 Dec 21. doi:10.3390/ijms24010059