By Dr. Derek Reinke, board-certified orthopaedic surgeon specializing in sports medicine
This is a frequent question I am asked at Cary Orthopedics. Some studies have shown a higher rate of arthritis in runners while others have shown no association or possibly a benefit to running. A recent study in the Journal of Bone and Joint Surgery provides some interesting information. The study, performed by Danielle Ponzio and others, is titled “Low Prevalence of Hip and Knee Arthritis in Active Marathon Runners.” The study consisted of a survey of 675 international marathon runners.
Participants had to have completed five marathons and still be active runners, running a minimum of 10 miles per week. The athletes were asked a number of questions about their running history, mileage and frequency as well as any previous diagnosis of arthritis, knee pain or prior surgery. The study was comprised of very active individuals, averaging 36 miles of running per week. They also had run for an average of 18 years with an average age of 48 years old and completed an average of 75 marathons. All subjects were asked if they had previously been diagnosed with arthritis by a physician, and then the results were then compared to the U.S. population at large.
The study found that 9% of marathon runners had been diagnosed with arthritis compared to the US population at 17.9%. As in the general population, runners who were older, female and heavier tended to have arthritis at a greater rate although this was still lower than the general population matched for age. A family history of arthritis, as well as a prior history of hip or knee surgery, were significant risk factors in both populations.
The study found no correlation between pain and arthritis with running duration, intensity, weekly mileage or the number of marathons completed. In fact, an increased number of marathons was associated with lower rates of reported hip and knee pain.
The Journal of Bone and Joint Surgery quoted another study by Robert Hyldahl and others, which showed lower levels of pro-inflammatory markers in runners’ synovial fluid after running for 30 minutes. These authors surmised that running might have an anti-inflammatory protective effect on the articular cartilage and explain a lower rate of arthritis and pain in runners.
Ponzio felt that their study supported the benefits of physical activity in maintaining healthy joints. The only exception in runners was in a joint that had previously been injured and required surgery. In this group, there was a greater risk of arthritis. A large number of study participants had completed over 100 marathons, and if there was any cumulative adverse effect to running, it would be seen in these athletes. However, the rate of arthritis in these very active individuals was no greater.
This article, along with others, suggests that running is a safe activity for the knee and hip in most people. It is important for those who are starting a new running program to start slowly and build up the intensity and mileage over several weeks. This will allow the body to adapt over time and lessen the chance of the knee or hip injury or a possible stress fracture. Obviously, if you are having any symptoms with running such as pain or swelling, this is not normal. You should stop running and if this is a persistent problem, have this evaluated by a sports medicine physician.