LATERAL KNEE PAIN

By Robert Forster, PT

Pain on the outside of the knee is one of the most common complaints from marathoners we see as they build up the mileage in training. The usual culprit is excessive friction between the thick band of fascia on the outside of the thigh called the Illiotibial band, and the bump at the end of the thighbone (femur). In most cases, the pain is in one knee and not the other. This begs the question: why would only one knee hurt if both legs ran the same mileage? The answer, as in all one sided “asymmetric” marathon overuse injuries, a mechanical deviation in the pelvis on the injured or non injured side of the body.

Most often, the cause of IT band syndrome is a pelvic misalignment, causing a functional leg length discrepancy. When the pelvis is unbalanced, the joints of the “short” or “long” leg will make adjustments to compensate in an attempt to level the pelvis. Typically, the foot on the long leg side will over-pronate as a strategy to flatten the arch and functionally shorten that leg while the foot on the short side will typically supinate in an attempt to hold that arch up and functionally elongate that leg. Either of these subtle but significant compensations will cause aberrant forces to bear down on the vulnerable tissues on the outside of your knee. An effective rehabilitation program must not only treat the painful area, but also address the cause of injury by exposing and correcting the mechanical imbalance at the pelvis.

Anatomy and Function

The illiotibial band is a thick band of fascia that extends from the pelvis down along the outside of the thigh to attach below the knee on the outside of the lower leg bone called the tibia. The IT Band functions to stabilize the thighbone and knee during the weight bearing “stance” phase of the running or walking gait, and helps guide the lower leg as it swings forward through the air in the swing phase. Just before foot strike, the illiotibial band slides over a bony prominence on the outside of the knee called the lateral epicondyle. This irritates a structure called a bursa (a fluid filled sac much like an internal blister that is supposed to be there) which is designed to prevent friction between the bony prominence and the illiotibial band.

Pain Presentation

Illiotibial band problems may also present at the top end of this broad band of fascia running along the outside of the thigh. Either at the top, where it originates on the outside of the pelvis, or, much more commonly, at the lower end at the site of the bursa on the outside of the knee. This lower IT Band pain tends to appear suddenly on a run and it often becomes so severe you have to limp or stop the workout and walk home. While it does not represent a high degree of damage to the bursa or the IT band, it can be one of the most painful conditions runners suffer and it will stop you in your tracks. If you ignore the pain and continue to run, the pain will progress to daily activities including stairs, squatting and pivoting.

At the top of the IT Band where it attaches to the outside of the pelvis bone, the pain can come on more gradually and is typically much less intense but can be equally as persistent. Pain in either the top or the bottom should never be ignored because they can be very stubborn and difficult to resolve if you run through the pain for any period of time.

The pain typically limits your workouts rather quickly before it can cause significant damage to the bursa or the illiotibial pain. However, if pain causes you to limp or alter your gait in an effort to limit the pain, you are likely to cause excessive stress on other structures and cause additional, potentially more damaging injuries.

Rehabilitation

Alleviating marathon-training injuries requires the right treatment to the right structures. The first step in any sports rehabilitation program is to first get an accurate diagnosis. Most often, lateral knee pain in marathoners is an IT Band syndrome, but it is critical to rule out a meniscus cartilage tear and tendon injury before settling on a diagnosis. The primary approach to all IT Band syndromes is to address the inflammation and pain at the injury site while simultaneously working to limit the amount of pronation in the foot when you run. Ultimately, this involves correcting leg length inequality with stretching and strengthening exercises. This takes some time but improving running gait mechanics can immediately start to reduce the pain.

Summary:

Lateral knee pain needs to be evaluated immediately to rule out problems in the joint itself. Local icing and PT treatment at the painful site will help, but ultimately we need to address the leg length discrepancy for total resolution of the problem. We will teach you stretching and strengthen exercises to correct your alignment and work with you to improve your running mechanics.

Call Forster Physical Therapy for your free evaluation. 310-656-8600

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