Osteoarthritis

The International Association for the Study of Pain (IASP) has designated 2016 as the “Global Year Against Pain in the Joints”. One of the most common causes of joint pain is Osteoarthritis (OA). In fact, 20% of chronic pain worldwide is associated with OA. The most commonly affected joints are the knees, hips, fingers and toes. OA is most common in people over the age of 65.

Symptoms

The most common symptoms of OA are:

• Stiffness/tension in the joint, which is particularly worse after resting;
• Limited range of motion/mobility;
• “Clicking” or “crunching” or “scraping” sounds and/or sensations in the joint;
• Swelling (inflammation) within or around the joint;
• Pain.

These symptoms generally progress with age and activity, although, the underlying cause of OA and symptom progression is multifactorial and not entirely understood.

Cause

Previously, OA was thought simply to be caused by general mechanical wear and tear of the joints; however, it is now recognised as a degenerative disease of the joints, with numerous risk factors. Major factors contributing to the development of OA include weight (the main risk factor second to age), genetics, joint injury and joint overuse.

• Weight: Research suggests that excess fat tissue produces proinflammatory adipokines (cell-signalling proteins that are secreted by fatty tissue). An excess of these molecules induces inflammation, which can cause joint damage. Increased mechanical loading due to excess weight also contributes to accelerated cartilage breakdown.
• Genetics: Research has identified numerous genes that may be associated with an increased susceptibility to OA. Primary gene candidates include those coding for collagen and other structural proteins and inflammatory molecules. Single genes alone may not be enough to infer an increased risk of developing OA, however, the interactions between genes and environmental factors, such as obesity, may account for a significant portion of OA risk.
• Joint Injury & Overuse: Overuse of the joints, injuries and muscular imbalance, all lead to accelerated cartilage breakdown and are also risk factors for OA development. Research shows that this may not simply be due to cartilage damage and increased wear and tear. Increased levels of inflammatory and degradative molecules have been detected in patients with knee injuries, which, as mentioned above, can give rise to an extra level of joint damage.

Treatment

Unfortunately, there is no cure for OA. Contrary to popular belief, however, the symptoms of OA are not inevitable. Various medical treatments and management strategies exist that aim to alleviate OA associated pain, improve mobility and function, and slow the progression of OA.

• Medications: Over-the-counter analgesic medications include Acetaminophen, which has specifically demonstrated effectiveness for people with OA, and nonsteroidal anti-inflammatory drugs, such as ibuprofen. For stronger pain relief, opioid medications, such as oxycodone and tramadol, may be prescribed by a doctor.
• Physical Therapies: Exercise is one of the most effective ways to manage OA. While it may be painful, light exercise has actually been shown to reduce pain. Strengthening the muscles around the affected joint can also reduce the pain. Increasing joint flexibility will help to regain motion in the joint. Exercise is also beneficial in that it can help with weight loss and maintenance. A physiotherapist can develop an individualised exercise program to help a patient manage their OA.
• Injectable & Surgical Treatments: Injection therapy can also help to reduce OA pain. Injected agents include corticosteroids and hyaluronic acid. There is growing evidence to also support the use of platelet-rich plasma and Botox injections. In cases of severe, refractory OA pain, invasive surgery is an option and includes joint replacement and bone realignment.
• Other Management Strategies: An occupational therapist can assist with reducing the burden of home and work activities by developing ways to reduce the associated stress and pain. Assistive devices are also available to OA patients. Studies have shown that some dietary supplements, such as chondroitin and Vitamin D, may reduce the progression of OA.

References & Further Reading:

1. International Association for the Study of Pain. 2016 Global Year Against Pain in the Joints. 2016; http://www.iasp-pain.org/GlobalYear/JointPain.
2. http://www.arthritisvic.org.au/Conditions-and-Symptoms/Osteoarthritis
3. http://www.arthritis.org/about-arthritis/types/osteoarthritis/
4. National Institute of Arthritis and Musculoskeletal and Skin Diseases. Osteoarthritis. 2015; http://www.niams.nih.gov/Health_Info/Osteoarthritis/default.asp
5. PubMed Health. Osteoarthritis: Overview. 2014; http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0072773/
6. Image by BruceBlaus (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons. https://commons.wikimedia.org/wiki/File:Osteoarthritis.png
7. Garne Mr, Alshameeri Z and Khanduja V. Osteoarthritis: genes, nature–nurture interaction and the role of leptin. Int Orthop. 2013; 37:2499-2505. http://www.ncbi.nlm.nih.gov/pubmed/24036528
8. Thijssen E, van Caam A, van der Kraan PM. Obesity and osteoarthritis, more than just wear and tear: pivotal roles for inflamed adipose tissue and dyslipidaemia in obesity-induced osteoarthritis. Rheumatology. 2015;4:588-600. http://www.ncbi.nlm.nih.gov/pubmed/25504962
9. Papathanasiou I et al. Molecular changes indicative of cartilage degeneration and osteoarthritis development in patients with anterior cruciate ligament injury. BMC Musculoskelet Disord. 2016;17:21. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4712525/
10. Goodwin JL, Kraemer JJ and Bajwa ZH. The use of opioids in the treatment of osteoarthritis: when, why, and how? Curr Pain Headache Rep. 2005;9:390-398. http://www.ncbi.nlm.nih.gov/pubmed/16282039