How To Thrive With Knee Osteoarthritis
How To Thrive With Knee Osteoarthritis
Despite a diagnosis of arthritis of the knee, the majority of these individuals can live a pain-free, active and high quality of life. We just need to change the narrative about osteoarthritis of the knee - bone on bone, degeneration, bone spurs and wear and tear does not mean you are destined to be in awful pain and can not lead an active life.
Too often healthcare professionals will tell you that you wore away your cartilage, you may have been told that running caused your knee joint to wear out, or that you walked too much at work for too many years. These theories are wrong.
1. Arthritis development is a biological process, not a mechanical one
Typically, we hear of knee osteoarthritis pertaining to mechanical wear and tear, but in actually fact it is a biological process that is set in motion many years before we start to feel the affects of arthritic knee pain. In our joints, we have 100's of proteins, cytokines, chemicals, and other compounds which are made by the synovium, or the lining of the knee joint. When our joints are healthy, the chemicals in our joint support cartilage health and nutrition.
Whether it is due to injury, or our metabolism, weight, and diet — a switch flips. Changes occur in our knee joint that is similar to the changes associated with other chronic disease states - diabetes, heart disease and high blood pressure. That switch turns on genes in our DNA that increase the production chemicals that are hostile to the health of our cartilage. So over time, an increase in those unfriendly chemicals eventually causes cartilage cell injury. The cartilage is the cushioning in the knee that protects the knee from developing knee arthritis. This weakens the cartilage and its ability to withstand stress.If the cartilage is not functioning well, or if it becomes thinner, it can lead
pain, inflammation, warmth, and swelling.
Osteoarthritis appears to be caused by low-grade chronic inflammation. This is the same chronic inflammation held as a cause of other chronic diseases such as Type 2 diabetes, heart disease, and fatty liver. Osteoarthritis is similar in that it may be caused by poor metabolic health. It may also have been caused by an injury that occurred 20 years ago. One bleeding episode in the knee can initiate the process. Surgery can start an arthritic process too. Having a meniscus tear, and certainly having that tear removed compounds the problem. That adds a mechanical issue to the inflammatory biological issues- the perfect storm for osteoarthritis and a good reason to avoid meniscus surgery if you can.
Osteoarthritis appears to be a result of poor metabolic health, which in turn can switch a gene in our DNA that increases cartilage damaging chemicals causing low grade inflammation and cartilage cell injury.
2. Osteoarthritis is less common in runners
This study shows that running was associated with a decrease in the cytokines or the chemicals in the knee related to cartilage wear and degradation.
Exercise has been proven to decrease the concentration of proteins and compounds in our knees that are hostile to cartilage health. In this study, IL-10, a cartilage protective chemical in the knee, was produced in response to exercise. Also, the concentration of a compound called COMP decreased within the knee with exercise. COMP is a protein that is felt to be a biomarker of cartilage degeneration,
Individual experiments have proven that the concentration of those nasty chemicals in our knee will go down after running, or resistive exercise. Studies have also shown that the health of our cartilage is positively affected by running. Our cartilage seems to like the cyclical loading associated with certain activities.
3. Bone on bone or degenerated cartilage is not causing you pain
Believe it or not, the bone on bone arthritis of the knee may not be a “pain generator.” There are no nerve endings in the bone itself. So if two bones are rubbing together and all else is well, they won’t hurt. The cartilage in the knee also does not have nerve endings in it. So thinning cartilage will not hurt in and of itself.There are three main contributors to the pain experienced by people with osteoarthritis of the knee:
1. The periosteum - the periosteum is a thin tissue that wraps around the bone. It supplies blood to the bone, and it does have nerve endings. It is the tearing of the periosteum that leads to a lot of the pain.
2. Synovitis - the synovium is the lining of the knee joint, it surrounds the bones of the knee and there are many nerve endings there. Synovitis is inflammation and swelling of this lining tissue or synovium.
3. Bone oedema or inflammation - when the knee cartilage thins, the cushioning action is also diminishing. Together with weakness in the quadriceps that can not absorb force as well, the less cushioning may cause increased stress in the bone, which can cause oedema and a deep, intense ache.
4. Exercise can improve your arthritic knee
Metabolic issues are felt to have a causative role in the development of osteoarthritis and other chronic disease states. This systematic review showed that the chemical composition of knee cartilage is not adversely affected by exercise, while many studies show that knee pain from arthritis improves with exercise. This study contributed sufficient evidence to show significant benefit of exercise over no exercise in patients with osteoarthritis. Exercise improves pain, strength, and decreases muscle atrophy - especially in targeted strengthening of quadriceps, calf and hamstring muscles. Ultimately, exercise can improve your quality of life and help delay the need for surgery. The Royal Australian College of General Practitioners (RACGP) also put out a "Guideline for the management of knee and hip osteoarthritis. Second edition 2018" that includes strong recommendations for land-based exercise - this means feet on the ground type strength training opposed to aquatic exercise.
"We strongly recommend offering land-based exercise for all people with knee OA to improve pain and function, regardless of their age, structural disease severity, functional status or pain levels"
5. Muscle mass, strength and mortality
One of the most intriguing reports relating body composition and muscle strength to knee osteoarthritis was this study, that showed that reduced quadriceps strength relative to body weight and lean muscle mass was a risk factor for development of knee osteoarthritis. This systematic review found similar results - that walking and home based quadriceps strengthening exercise reduced pain and disability related to knee osteoarthritis.
This study found quadriceps muscle strength was significantly associated with knee pain. The quadriceps muscle is the principal dynamic stabiliser of the knee joint; thus, quadriceps muscle weakness leads to instability of the knee, which may be one of the reasons for knee pain. This also means that knee pain may be prevented by muscle exercise.
Finally, this study is one of many that showed lower muscle strength and muscle mass and greater declines in strength over time are associated with increased risk of mortality.
6. Why we should focus on leg strengthening interventions
Leg weakness, in particular quadricep weakness, is clinically important in individuals with osteoarthritis because it is associated with physical disability, an increased rate of loading at the knee joint itself and has been identified as a risk factor for the initiation and progression of knee joint degeneration. Most of the literature have observed quadriceps strength deficits of 20 to 45% in people with knee joint osteoarthritis. Part of this weakness is due to muscle atrophy (reduction of muscle size) and part due to arthrogenic muscle inhibition. Arthrogenic muscle inhibition leads to marked quadriceps weakness that impairs physical function and may hasten disease progression. It was observed in individuals with severe knee osteoarthritis, arthrogenic muscle inhibition appears to account for a greater portion of quadriceps weakness than muscle atrophy.
Most of the literature have observed quadriceps strength deficits of 20 to 45% in people with knee joint osteoarthritis.
7. Can stronger legs help prevent knee osteoarthritis?
The short answer... Yes.
According to Mayo Clinic researchers individuals with stronger quadriceps muscles in their legs can help protect against cartilage loss behind the kneecap. Further, those who had greater quadriceps strength had less cartilage loss within the lateral compartment of the patellofemoral joint (between the femur (thigh bone) and patella (kneecap), which is frequently affected by osteoarthritis - a stronger quadriceps muscle helps keep the patella from moving laterally and tracking abnormally with movement. A 2015 article found that people with osteoarthritis, there was asymmetrical deficits in knee extensor (quadricep) and flexor (hamstring power) power between 18% and 29%.