What You Need to Know About Runner’s Knee

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by Dr. Richard Beauchamp M.D., FRCSC

Have you experienced pain around the front of your knee(s) during or after a run? If so, you may have had a case of runner’s knee. Runner’s knee is actually a vague term used to describe the above symptom—pain in the knee. However, it is not necessarily a precursor of arthritis; in fact, it has been said that there is no correlation to hip and knee arthritis in active marathoners.1

Runner’s knee is a common condition, but the actual causes and effective treatments are not easily explained. Runner’s knee is a grab bag of other diagnoses and conditions often aggravated by the pounding of the legs on the ground during your sport. Your legs have to generate force in order to run, as well as absorb force in order to protect your bones and muscles from injuries. Runner’s knee can also occur in walkers, although not as frequently.

Causes
There are two broad categories: intrinsic causes (from actual conditions inside the knee joint) and extrinsic causes (from other adjacent parts of the body which affect the knee). Intrinsic causes for runner’s knee can include injuries to the cartilage, ligaments or tendons inside the knee joint. These are often seen in an acute injury, such as a fall, and can account for knee pain. However, this is not a true reflection of the syndrome of runner’s knee. Extrinsic causes for runner’s knee are much more common. They can include anatomical alignment issues, muscle weakness or overuse syndromes. Every runner has a unique build and running pattern that may contribute to the knee pain.

Malalignment syndromes of the lower extremities can precipitate the development of knee pain, usually through an abnormal pull of the muscles on the kneecap (patella). Knock knees or bowlegs can produce abnormal patello-femoral movement (also known as “tracking”) and subsequent knee pain as well.

Most cases of runner’s knee are actually due to a combination of quadriceps (thigh) muscle weakness and poor tracking of the kneecap on the femur (thigh bone). This poor tracking can be from misaligned body parts in the foot, leg or pelvis.The anatomical alignment of the quadriceps tendon and muscle at its attachment to the kneecap is described as the “Q angle.”

An increased Q angle usually refers to excessively loose tracking of the kneecap leading to knee pain and, at times, eventual kneecap dislocations. This poor tracking can lead to some degree of cartilage degeneration under the kneecap causing pain felt mainly over the front and inside areas of the knee joint. This is often referred to as chondromalacia patella. The whole syndrome of runner’s knee and chondromalacia patella is often referred to as Patello-Femoral Stress Syndrome (PFSS).

Diagnosis
A giveaway sign of runner’s knee is downhill running. This action can be especially sore for a runner suffering from runner’s knee, mainly because of the unique muscle pull that is needed by the quadriceps when you are braking and slowing down, trying to keep your legs under control. Sitting in one position for a prolonged period and then standing up often exacerbates the symptoms of runner’s knee—this is called a positive theatre sign. There is usually no knee pain present at rest.

When you visit your doctor for this condition, he or she may want to look for any other conditions that may require further treatment than is offered below. An x-ray may be ordered to look at the bony anatomy and ensure you don’t have any unusual tumours or cracks in the bone. A Magnetic Resonance Image (MRI) may also be helpful to view the cartilage, meniscus and ligaments.

Treatment
Like any other running injury, the best initial treatment for runner’s knee is undertaken by the runner. This means careful reviewing your running history and identifying any predisposing factors such as an excessive recent increase in distance and speed, worn out running shoes, or the addition of recent hill training. Perhaps you can alter some of these factors and your symptoms may subside. If that is not successful, you should consult your health care provider. If you have a knee that frequently locks up and does not bend or straighten properly, or is so loose that you cannot rely on it to properly support you, you should check with your physician. On the other hand, if you have more complaints related to knee pain without the above issues, then you need to have a leg alignment and general biomechanical assessment of your lower extremities (including spine and pelvis) by a therapist specializing in sports injuries.

The most frequent treatment for  runner’s knee usually involves a combination of strengthening the quadriceps muscle (often the “VMO” component), stretching any opposite muscles that may be tight (such as ITB and hamstrings) and possibly altering your shoe wear or incorporating a foot orthosis in your running shoes. Sometimes your therapist or doctor may prescribe a knee brace or orthoses.

Once you begin an appropriate treatment program for runner’s knee, it may take several months for the symptoms to subside. You can help prevent recurrence by maintaining adequate quadriceps strength (using weights) and ensuring your footwear is supportive.

 

References:

1. J Bone & Joint SurgVol. 100, pg. 131-137, Jan. 2018.
2. J Applied BiomechanicsVol. 34, pg. 76-81, Feb. 2018.

 


Dr. Richard Beauchamp is an orthopedic surgeon based in Vancouver. He is the medical director of the Shriner’s Gait Lab at Sunny Hill Health Centre and a clinical professor in the Department of Orthopedics at the University of British Columbia. He is an avid runner and walker who has completed seven marathons.

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