What is going on with my KNee?
Have you had to tell friends that you can’t go hiking, jogging, skiing or walking because of a sore knee? Have you had to reconsider doing activities that you once loved to do because of knee pain? Has your physician told you have knee arthritis? Knee osteoarthritis is very common in society. It is estimated that close to 32.5 million people in the United States have some form of arthritis, with knee joint osteoarthritis being the most common.
Women tend to have more cases of arthritis than men. Osteoarthritis (latin for bone and joint inflammation) occurs when a joint becomes chronically inflamed and painful. This is primarily due to the body’s immune response trying to heal your aging, wearing thin, shiny white cartilage cushions at the end of your bones. This can happen gradually or be accelerated from a bad knee joint injury in your past. When swelling and pain-producing chemicals accumulate in your joints, they irritate pain and pressure receptors in that joint, leading to a pain response in your brain. There are no nerve endings in the shiny white articular cartilage of your joints, but there is in the bone behind the cartilage. So, typically the pain you feel from the initial stages of joint irritation it is irritation of the surrounding tissue in and around the joint.
factors that lead to knee joint osteoarthritis:
Age- As we get older our joints get gray hair and wrinkles on the inside. Our joints are not as robust as they once were, and self-repair and tissue turnover slows down as we age.
Heredity- Some families have a genetic history of premature joint arthritis. Some families have genetically inherited lower extremity malalignments such as being bow legged or knock kneed. This can change weight bearing pressures to only certain parts of your knees causing premature joint changes.
Auto immune diseases- Auto immune inflammatory diseases such as Rheumatoid arthritis, Lupus, Psoriatic arthritis, infective arthritis, etc. can lead to premature joint break down. Consulting your Dr. regarding these conditions is crucial for treatment and improved long-term outcomes.
Prior traumatic injury- An injury such as an osteochondral lesion, meniscus or ligament injury, articular cartilage injury, or fracture through the joint can permanently injure your joint surfaces. More importantly, a prior knee injury that was not fully rehabbed can lead to premature adverse joint changes. For example, studies show that meniscus (cartilage pads) surgeries that remove part or all the meniscus, can lead to joint micro-instability and ultimately premature joint pressures and wear. Other studies show that if you have had knee surgery or an injury and do not regain full joint ROM, this can lead to premature arthritic change in the knee. Further, habitually poor biomechanics from an injury or weakness in your hip or foot and ankle can place increased stress through your knees.
Repetitive activities that regularly exceed your knee’s strength, power, endurance and ROM capacity can place increased stress on your knee joint surfaces. Especially, if you do not give your joints a chance to heal and recover between intense workouts and injuries. You must progress weight bearing exercises appropriately and proportionately. You can’t start running marathons if you haven’t built up the volume correctly. The principles explained in mechanotransduction (mechanical stress transformed into gene activation), Davis’s Law (soft tissue) and Wolff’s Law (bone) state that when you stress a tissue it will respond by creating the same and more resilient tissue that you are stressing. However, if you overload a tissue without giving it a chance to heal and regenerate, it will break it down. Therefore, an organized and progressive overload stress is required to prepare our bodies tissues for the demands we place on them. One of the keys to decreasing injury, as much as we are able to, is being strong and flexible enough to tolerate what you are doing to your joints. We need to build capacity. When we exceed our tissue capacity, we get injured. Further, by building your training volume slowly, you allow your tissues to adapt. The goal is to produce an anabolic (build up) stimulus, not a catabolic (tearing down) stimulus.
Obesity- carrying extra weight above your ideal weight places extra stress on your weight bearing joints. Some research states that for every 1 lbs of body weight you lose you reduce the stress to your knee joints by 4 lbs. For those people who backpack, think about how sore your knees are after back packing with a 30, 40, or 50 lb pack on, and then how you feel when you take it off?
Poor diet, metabolic issues and excess body fat are hard on our joints. When we carry extra body weight, specifically belly fat, the fat tissue releases hormones called adipokines. These hormones can be found in our joints, especially those of obese people. These hormones circulate throughout our bodies and accumulate in our joints leading to increased low-grade inflammation and cartilage damage. Chronic presence of these chemicals leads to cartilage thinning and decreased joint resistance to stress. Our joint cartilage is sensitive to our dietary choices as well. It is well known that certain foods and drinks cause increased system wide inflammation. For example, diets high in sugar, alcohol, carbs and acidic foods are inflammatory. Chronic inflammation can lead to tissue scarring and persistent nerve irritation.
How can physical therapy help?
A PT can help educate you on your symptoms, beliefs about movement, exercise and pain, and how to start to improve your condition.
PTs can provide a strength, range of motion (ROM), balance and coordination assessment of your lower extremities and spine to identity what’s impacting your knee
A PT can assess old injuries and their impact on your knee. Do you have an old back injury with some subtle, lingering leg weakness or tightness? Do you have an old severe ankle sprain that you didn’t fully regain all its ROM? Are you lacking adequate hip mobility? Are the muscles in your foot weak?
As manual therapists, we can provide gentle mobilizations and soft tissue work to improve joint mobility and decrease pain. We can help train your joint’s awareness and proprioception so it can handle unexpected stresses and strains with more resiliency.
Physical therapists can design an individualized program with corrective ROM and strengthening exercises for your trunk, hips, knees and feet. We can design a daily/ weekly maintenance home program for your knee. We can also give you a program for progressive return to activity and progressive loading to facilitate improved tissue strength and tolerance. Further we can help you understand what to avoid and what’s okay to do with your knee.
Physical therapists can help you with understanding your step cadence (step rate) while running. Studies show that over striding increases stress to your lower extremities. Increasing your step rate by 5% but keeping speed constant, can decrease the stress on your knees by 20%! Heiderscheit, B et al., 2011 7. We can give you advice on shoe wear and/ or orthotics/ arch inserts and if they are right for you.
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References
Tanaka R et al. Efficacy of strengthening or aerobic exercise on pain relief in people with knee osteoarthritis: a systematic review and meta-analysis of randomized controlled trials. Clininical Rehabilitation. 2013 Dec;27(12):1059-71
Uthman OA et al. Exercise for lower limb osteoarthritis: systematic review incorporating trial sequential analysis and network meta-analysis. BMJ. 2013 Sep 20;342014 & Nov;48(21):1579
Tanaka R et al. Does exercise therapy improve the health-related quality of life of people with knee osteoarthritis? A systematic review and meta-analysis of randomized controlled trials. J Phys Ther Sci. 2015 Oct;27(10)
Li, Y et al. The effects of resistance exercise in patients with knee osteoarthritis: a systematic review and meta-analysis. Clinical Rehabilitation. 2016 Oct;30(10):947-959
Zacharias A et al. Efficacy of rehabilitation programs for improving muscle strength in people with hip or knee osteoarthritis: a systematic review with meta-analysis. Osteoarthritis Cartilage. 2014 Nov;22(11):1752-73
Fransen, M. Exercise for osteoarthritis of the hip or knee. Cochrane Database Syst Rev. 2003;(3).
Goh, SL et al. Efficacy and potential determinants of exercise therapy in knee and hip osteoarthritis: A systematic review and meta-analysis. Annals Physical Rehabilitation Medicine. 2019 Sep;62(5):356-365
Bartels, EM et al. Aquatic exercise for the treatment of knee and hip osteoarthritis. Cochrane Database Syst Rev. 2016 Mar 23;3
Allyn M et al. The pain-relieving qualities of exercise in knee osteoarthritis. Open Access Rheumatology: Research and Reviews 2013:5 81–9
Horga, LM et al. Can marathon running improve knee damage of middle-aged adults? A prospective cohort study. BMJ Open Sport Exerc Med. 2019; 5(1)
Heiderscheit, B et al. Effects of Step Rate Manipulation on Joint Mechanics during Running. Med Sci Sports Exercise. 2011; 43(2): 296–302