Knee osteoarthritis (OA) affects more than one third of people over the age of 50. Although it is almost as common as hypertension in the ageing population, confusion remains surrounding the condition itself and how to best manage it. Today’s column will provide you with a good understanding of the condition as well as the recommended evidence-based guidelines for managing knee OA.
Similar to wrinkles in skin or graying hair, your body’s joints will undergo normal changes with time. In fact, a study showed that these degenerative changes were seen in knee x rays of 85% of asymptomatic, pain-free adults. This simply highlights the fact that many adults live comfortably and are able to continue their activities regardless of having osteoarthritis in their knees.
OA affects the moveable joints of the body, most commonly the weight bearing knee and hip joints. It is characterised by cell changes that lead to mechanical and chemical wear of the smooth cartilage that lines the ends of the bones. The bones respond by producing bony spurs called osteophytes to stabilize the joint. In some cases, the progression of this condition may lead to important functional limitations that can affect walking capacity and cause pain and stiffness, particularly in the morning.
Some younger adults will develop what is called secondary OA. In this case, joint changes occur following a trauma, metabolic disease, congenital malformations or hormonal shifts. Unlike other inflammatory arthritic conditions such as rheumatoid arthritis or ankylosing spondylitis that are autoimmune in nature, the presence of inflammation is inconsistent and is not clearly a cause in knee OA.
Risk factors for developing knee OA have been well studied. Age, gender, previous injury, genetics and bony alignment all have an influence on developing knee OA. However, none of these risk factors are easily modifiable! Since our column focuses on proactive health, we will highlight the factors that you CAN readily influence through lifestyle changes.
The factors that you should consider if you experience pain and limitations are: excessive joint loading, strength and control of the muscles of the hip and knee and finally, excess body weight. Pain most often occurs if the load of your activity surpasses the tolerance of your joint tissue. In the case of OA changes, the joint tolerance level may be diminished so it may take less load than expected to cause pain.
For example, imagine that your gutters are filled to the brim with leaves this fall. You spend several hours kneeling on your roof getting the job done. This seemingly effortless activity may, for someone with knee OA, be just enough to create an inflammatory response in your knees.
Abnormal loading of your joint surfaces can also come from poor joint stability. Either due to previous injury and/or normal OA progression. The good news is that your tissues are adaptable. And the ability to handle load can be improved through the right exercises. Keeping your joints in a stable position relies on the strength of the muscles (quadriceps, hamstring and gluteus muscles particularly) as well as efficient control of your limb movements. This is how exercise contributes to slowing down the disease progression.
The last factor to consider is weight gain. The studies consistently demonstrated being obese or overweight was a risk factor for the onset of knee OA. A study determined that obesity can contribute to a generalized inflamed state. It signals chemical reaction that leads to joint degradation. Think of it this way. For every 1 lb increase in weight, the overall force across the knee when standing on one leg is 2-3 lbs! Weight loss does not need to be major in order to decrease symptoms. A ten percent weight loss through diet and exercise in a year can lead to a fifty percent reduction in knee pain from OA!
Low-impact aerobic exercise is most recommended to people who suffer from knee OA. This keeps the joints moving and lubricated, to maintain strength and to help manage weight. Good examples of such physical activities include stationary cycling, water-based exercises and urban poling/nordic walking. Remember to progressively build up your capacity to tolerate load. It’s best to start with a few short bouts. As opposed to starting with 20 consecutive minutes if you have not been active in a long time.
The consensus for first-line treatments of patients suffering with OA are as follows; education and support about the condition and a personalised activity plan that targets strength, aerobic activity and weight loss. When pain management is not sufficiently met with the above recommendations, second-line treatments are considered. These treatments include appropriate pharmacotherapy, topical creams, bracing and walking aids.
We hope that the information presented clarifies some of the common misconceptions about osteoarthritic change. We hope it sheds some light on what is currently recommended to improve your pain management and overall function. Currently, there is one most limiting factor to helping people suffering from OA. It is the disconnect between the information contained in these guidelines and our ability to put them into practice. Let’s get the message across that the right motion is lotion to your knees!
Article written by Karine Tcholkayan pht and Amy Rogerson pht
Amy and Karine are registered physiotherapists, both holding a Master’s degree in Physiotherapy and Bachelor of Science in Exercise Science.