By the very nature of the activity, running puts a tremendous amount of stress on the feet, ankles, shins, knees, hips and back. Consequently, aches and pains in the muscles and joints of the lower legs are not at all uncommon.
One area in particular that may become a chronic problem is the knee.
The knee is a complicated joint made up of four bones (femur, tibia, fibula and patella), four major ligaments (anterior and posterior cruciate and the medial and lateral collaterals) and numerous tendons. Additionally, the femur and tibia are lined with shock-absorbing cartilage that keep the joint moving smoothly.
Any of these structures can become damaged either acutely or from wear and tear. When this happens, pain is invariably the symptom that is experienced, though it need not be constant. Sometimes pain is only felt when putting the joint through certain movements, while other times it is felt only with weight bearing.
Whatever the nature of the symptoms, identifying the cause for the pain is often difficult but it is nonetheless critical. Ignoring a knee injury is done at great risk of worsening the damage or causing additional injuries.
“Runner’s knee” is the term given to a range of overuse injuries that often afflict runners and cause pain in the front of the joint. Some of these issues arise from biomechanical or structural problems but many come about simply from doing too much too quickly. Of the various injuries that are encompassed in ‘Runner’s knee’ two are the most common: patellar tendinitis and patellofemoral pain syndrome.
The knee cap is a mobile bone that is completely encapsulated in a thick tendon sheath. At the top, this tendon connects to the large quadriceps muscle that lies on the front of the thigh while at the bottom the tendon connects to the front of the tibia or shinbone.
Repeated stress on the tendon while running may cause microscopic tears within the structure. Swelling then occurs as the body tries to heal itself and pain is perceived. Continuing to run through the pain can cause new tears and exacerbate the old ones leading to a chronic and difficult-to-heal phase called tendinopathy.
There are several factors that contribute to the development of patellar tendinitis. The use of inappropriate footwear and the surface being run on can both contribute to the development of patellar tendinitis. Training errors are also important and can be summed up by the rule of “toos”. This refers to training too much, too far, too fast or too long. Advancing the training schedule forward too quickly is a major cause of patellar tendinitis.
Muscle strength imbalance as well as structural issues such as flat feet or knee joint laxity may also play a role in the development of this injury.
Pain from patellar tendinitis is almost always felt below the knee cap at the top of the shin. Pain is worst with bending the knee or kneeling.
Treatment of this condition is three-pronged and is aimed at 1) decreasing inflammation 2) allowing time for adequate healing and 3) alleviating whatever factors led to the problem in the first place.
To decrease inflammation, non-steroidal anti-inflammatory (NSAIDs) medications such as ibuprofen are quite effective. In addition, frequent applications of ice to the affected are may also be helpful. While a complete cessation of activity may not be necessary, it is important to refrain from any activities that exacerbate the pain. In mild cases, running at low intensity for short durations may be possible but for many this is not the case. To ensure adequate healing, rest and recovery should take place until the joint is pain free. During this period and immediately thereafter, strengthening exercises of the quadriceps and the ankle are beneficial to prevent recurrence and are to be encouraged. Finally, it is important to address any issues related to footwear, arch support and the training program in order to prevent patellar tendinitis from coming back.
Patellofemoral Pain Syndrome
As the knee joint is ranged from straight to fully bent, the patella moves upwards over the femur in a groove. If the patella runs through this groove in an inappropriate way or if the patella rubs against the femur as it slides in the groove, the underside of the knee cap may become inflamed and injured resulting in pain. This situation is known as the patellofemoral pain syndrome (PFPS). Left unchecked, the cartilage underneath the patella may become damaged leading to the more severe condition chondromalacia.
PFPS is the most common cause of knee pain in all patients, not just runners. The symptoms are fairly characteristic and include pain around or behind the knee cap that is accentuated by going up or down stairs.
Once established, it is important to treat PFPS or it may progress to chondromalacia which can be more painful and take longer to heal. Management is similar to patellar tendinitis in that rest along with the use of ice and NSAIDs may help diminish pain and swelling. Furthermore, strengthening of the quadriceps muscle is of the utmost importance as it is this muscle that stabilizes the patella and guides it properly through the groove with bending of the knee.
Many other treatment options have been evaluated for PFPS including the use of braces and taping but these have not been shown to be beneficial.
There are other overuse injuries that are occasionally considered when evaluating ‘runner’s knee’ but these are far less common and often more difficult to diagnose. So how should you proceed if you have knee pain and believe that you have ‘runner’s knee’?
First and foremost, take a day or two to rest. Do not run on a knee that is painful, you will only make things worse. If you are unable to bear weigh on the injured leg or if you have swelling of the joint, these are signs that you may have more important structural damage to the ligaments or cartilage and in these cases, evaluation by a physician is strongly recommended.
In the absence of these red flags, a trial of ice and NSAIDs is appropriate. If after a few days of rest the pain has subsided, begin a strengthening program for the quadriceps and ankle flexors of the lower leg. Replace your shoes if necessary with new ones that are suited to your running style. Use arch supports if needed. After a week or so, continue the strengthening exercises and resume running on a soft surface but at a much reduced volume and intensity. If the pain does not return, slowly increase the frequency, duration and finally intensity of the runs over a period of at least a month. If at anytime the pain returns, evaluation by a physician is probably a good idea.
Train hard, train healthy.
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About the Author:
Jeffrey Sankoff, MD is a three time Ironman and 70.3 World Championship qualifier. He is an Emergency Physician at Denver Health Medical Center in Denver.