As a recreational marathon runner I am frequently asked by non-runners, “How are your knees holding up? Aren’t you afraid you will get arthritis in your knee and need a knee replacement from running marathons?” It is undeniable that running related injuries are high, and any other disease or dysfunction at up to 79% within a community would be considered epidemic proportions. The injury rates are scary to me, but what is absolutely maddening to me, is people frequently throwing around the arthritis word as if every and only runners would be afflicted with it. In this blog post I will define “arthritis” and I will offer a glimpse of what the research says about what populations are at greatest risk.
More than 100 rheumatic diseases exist, but the two most common types are rheumatoid arthritis (RA) and osteoarthritis (OA), often times just referred to as arthritis. Although the etiology, risk factors, and prevalence of RA and OA are different, they are both characterized by pain in the joints and debilitating functional limitations (Stone & Baker, 2014). The largest difference in RA and OA is in their physiological mechanisms. The exact cause of RA is unknown and is considered an autoimmune disease which is possibly the result of an interaction between genetic disposition, environmental factors, and chance. RA is a systemic inflammatory disease linked to cardiovascular, pulmonary, and gastrointestinal diseases, in addiction to cancer and is sadly observed more in females (Gibofsky, 2014). The good news is, US studies have noted a progressive decline in RA prevalence since the early 1960s (Helmick et al., 2008).
Osteoarthritis (OA) is distinguished by degeneration of the articular cartilage, progressing to eventual cartilage loss, creating a bone on bone scenario of weight bearing joints, most commonly the knee and hip. OA is the leading cause of knee and hip joint replacement (Rooney, 2004). The cause of OA is multifactorial with the largest contributing factors including, higher body mass index (BMI), previous traumatic knee injury, occupational activity, and increased age (Richmond et al., 2013). I don’t know about you, but I did not see being a runner as one of the largest risk factors associated with OA or joint replacement. Unlike the prevalence of RA decreasing, previous research showed OA increased 22% from 1995-2008 (Lawrence et al., 2008) and continues to rise.
If you have read the “about” section on my website, you know that I work as a registered dental hygienist and I have done so for 19 years. One of the first things I do at the beginning of my patients appointment is to go over their medical history. I treat several patients a week that have had a joint replacement. I can say with certainty that I have never had a patient acquire arthritis or need a joint replacement from marathon running. I think we all are aware of the prevalence of overweight and obesity in our society. Does anyone think that the increase in osteoarthritis may be parallel with the overweight and obesity epidemic? Does anyone think that the increase in osteoarthritis may be parallel with the longer life expectancy due to medical interventions? Does anyone think that there are more traumatic youth knee injuries from early sports specialization more common in the last couple of decades? OA is actually highest in former female soccer players with a previous anterior cruciate ligament (ACL) injury and football players that take traumatic hits and are often times obese. You see large football players and although they may be athletes, I see a Ford 250 Extended Cab truck, rolling around on Honda Civic tires. Imagine it, those tires are going to breakdown sooner than later.
Runners can be at risk for OA if they constantly run through injury without proper treatment and time off, which cumulatively can lend itself to the previous injury risk factor. A runner and their coach if they have one, need to be mindful of the laws of biomechanics I wrote about in my injury epidemic blog post. If you haven't read that blog post, please do. A runner can also be at risk if they have poor mechanics with muscular imbalances. This would be similar to a car having it’s alignment off and the tires wear unevenly. The same thing can happen with the meniscus of the knee. However, these risk factors are extremely low for developing arthritis in the knee if not coupled with higher BMI, previous knee injury, occupational activity, and/or increased age. To say that runners will ruin their knees, get arthritis, or need a joint replacement because of running is a fallacy.
Runner Image: Ara Miralles
Gibofsky, A. (2014). Epidemiology, pathophysiology, and diagnosis of rheumatoid arthritis: synopsis. American Journal of Managed Care, S128-S135.
Helmick, C. G., Felson, D. T., Lawrence, R. C., Gabriel, S., Hirsch, R., Kwoh, C. K….Stone, J. H. (2008). Estimates of the prevalence of arthritis and other rheumatic conditions in the United States: Part I. Arthritis & Rheumatism, 58(1), 15-25.
Richmond, S. A., Fukuchi, R. K., Ezzat, A., Schneider, K., Schneider, G., & Emery, C. A. (2013). Are joint injury, sport activity, physical activity, obesity, or occupational activities predictors for osteoarthritis? A systematic review. Journal of Orthopaedic & Sports Physical Therapy, 43(8), 515-524.
Rooney, J. (2004). Don’t get out: Understanding the difference between osteoarthritis andrheumatoid arthritis. Nursing Made Incredibly Easy, 2(2), 26-35.
Stone, R. C., & Baker, J. (2014). ) Physical activity, age, and arthritis: Exploring the relationships of major risk factors on biopsychosocial symptomology and disease status. Journal of Aging and Physical Activity, 22, 314-323.