|Should You Continue Running?|
The effect of injury and osteoarthritis on running longevity.
What happens when the body sustains knee ligament injury or develops degenerative joint disease and the well-tuned running machine becomes compromised? Given how natural it is for us, should we continue running?
The research is now quite clear. Once a knee has undergone trauma such as Anterior Cruciate Ligament (ACL) rupture, post-traumatic osteoarthritis (OA) will develop. Within as little as twenty years post injury, radiological evidence of degenerative changes will be found in one hundred per cent of these knees. Magnetic Resonance Imaging (MRI) studies of these joints reveal typical signs of OA such as cartilage thinning, meniscal tears, bone marrow swelling, and osteophytes (small bony growths). Unfortunately studies are also revealing that continuing with impact sports like running will accelerate the progression of the OA changes. So even if you are not having pain or symptoms of joint irritability like swelling and stiffness, you can be guaranteed that if you have had ACL injury and you keep running, your knee is slowly deteriorating.
Within the ACL-injured population, one of the factors that seem to influence OA progression is alteration in joint mechanics. Abnormal rotation in the knee while running has been found in studies looking at both the reconstructed and non-reconstructed ACL-deficient knee. In theory this alters weight-bearing forces in the joint and leads to cartilage thinning and OA. Adult cartilage has low adaptation potential and is unable to compensate for the change in location of bumping and grinding. It is critical that symmetrical running gait patterns be restored as close to normal during rehabilitation to minimize the effect of these biomechanical changes.
Quadriceps weakness has been documented as a feature of knee OA in general and it is suggested that this weakness alters shock absorption at the knee joint and predisposes to further OA changes. We also know that timing of muscle function is compromised by pain and swelling. Rehabilitation including strengthening and coordination drills helps to minimize this impact of weakness.
The prognosis for any of the lower body joints (hip, knee, and ankle) is the same once osteoarthritis is present. If you have OA and you run, over time the OA will get worse. With ankle OA, weakness of the lower leg muscles has been documented as a common finding. As with the quadriceps and the knee, if the shin muscles are kept strong this may offer a buffering protection of the ankle joint. Once running mechanics are altered by a stiff ankle joint, cartilage surfaces will be subjected to abnormal wear patterns that may facilitate progression of degenerative joint changes.
Typical signs and symptoms of an OA joint are heat, swelling, stiffness, and pain. Just to be clear, these symptoms dos not necessarily mean you have OA. Other causes may be muscle imbalances that are irritable to the joints but not yet severe enough to cause cartilage changes. In these cases proper identification of the underlying asymmetries combined with appropriate rest and exercise therapy will likely get you back on the road or the trails without any worries for the future of your running career.
So, back to the original question: You have had an ACL injury or have known OA in your knee; should you continue running? There are several ifs involved in the answer. If you are asymptomatic (no pain, swelling, or stiffness), if you have good running mechanics with adequate range of motion and strength, and if you are willing to alter running goals like race distance and speed, then … maybe! We know for sure that if you have OA it will get worse with continued running. Intensity, frequency, and duration are all positively correlated with increased joint stress, so all of these factors need to be addressed. How many marathons do you really need to do at the expense of your joints? Could a ten-k or half-marathon race satisfy your desire for running without sacrificing your body? Walking, hiking, swimming, and biking are all great, safe alternatives to running. Ideally you should consult with a health professional like a sport medicine physician or physiotherapist about your specific options.
Our ancient ancestors probably never lived long enough to have to worry about stopping running because of OA. Back then life expectancy was well under forty. Osteoarthritis never had much chance to develop. Now, especially as fit, active people, we can expect to live well into our eighties. Respect and protect your joints; the originals are much better than the replacements!
About the Author
Louise Taylor is a physiotherapist with THE Downtown Sports Clinics in Calgary. Her training includes acupuncture and spinal manipulation, and her treatment style involves a strong emphasis on specific exercise to help rebalance the body.