Iliotibial Band Friction Syndrome
By Glenn Lindsay, PhysiCo
The average runner's foot strikes the ground approximately 3,000 times per mile. Over a 10 mile run that's 30,000 foot impacts, with each of these impacts bearing our entire body weight through the one leg. This is not the case with walking, where we have both feet on the ground around 30% of the time. Given the added momentum of running and the opposing ground reaction force, the actual force which each leg must withstand whilst running is roughly three times body weight. Indeed it is not surprising that a distance runner's knees are subject to significant stresses. Should your training be primarily on the roads of London in worn-out shoes with less than optimal shock absorption qualities, then these stresses will be even greater.
The knee joint is therefore not surprisingly a common site of injury for the runner. In fact, one particular knee injury is so common with this form of exercise that it is often called 'Runner's Knee'. The correct term is 'Iliotibial Band Friction Syndrome' (ITBFS), and although it is most commonly experienced by runners it is also seen with other activities such as cycling, ski-ing, soccer and weight lifting.
The iliotibial band (ITB) is a thick band of tissue that extends down the outside of the thigh from the ilium bone at the pelvis, over the knee to the tibia bone of the lower leg. More specifically, it attaches to the pelvis via the Tensor Fasciae Latae (TFL), which is a hip flexor muscle (ie bends the hip), and via the Gluteus Maximus muscle, which extends the hip. It passes over the knee joint to attach at the lateral tibial condyle (ie the outer part of the tibia bone just below the knee). The primary function of the iliotibial band is to provide static stability to the lateral aspect of the knee. To hopefully make this anatomical arrangement clearer, please see the diagram below. (My apologies for the quality, but I'm a physiotherapist, not an artist!)
Tensor Fasciae Latae
Lateral epicondyle of femur
Lateral condyle of tibia
Femur (thigh bone)
Patella (Knee cap)
So What Happens?
ITBFS is an overuse injury specifically referring to an irritation and subsequent inflammatory reaction of the lower iliotibial band. This occurs due to repetitive frictioning of the band as it rubs over the bony prominence of the lateral epicondyle of the femur during flexion (bending) and extension (straightening) of the knee. ie When the knee bends beyond 30 degrees, the iliotibial band moves behind the lateral epicondyle. As the knee straightens to less than 30 degrees, the band moves forward of the lateral epicondyle. Thus, during the running gait, bending and straightening of the knee repetitively and alternately shifts the iliotibial band forward and behind the lateral epicondyle.
As with most injuries of overuse, there are underlying factors which can contribute to the onset of ITBFS. These include both structural factors which are intrinsic to the runner and extrinsic factors. In runners, intrinsic factors include:
- genu varum (bow legs) leading to tightening of the ITB at the knee
- lateral knee ligament laxity leading to bowing of the knee due to excessive forces of body weight during running
- pes cavus (high foot arches) leading to a more rigid foot and decreased shock absorption at the foot and ankle. This therefore increases forces at the knee
- over-pronation (or excessive rolling in) at the ankle leading to excessive internal rotation and tightening of the iliotibial band as it crosses the knee
- leg length discrepancies which result in a lateral tilting of the pelvis and a tightening of the ITB, such as when excessive ankle pronation and internal tibial rotation occur in the longer leg in an attempt by the runner to equalize leg length
- a tight Tensor Fasciae Latae muscle which effectively tightens the ITB.
Extrinsic factors can include:
- footwear excessively worn on the lateral (outer) heel contributing to greater forces at the lateral aspect of the knee
- inflexible running shoes which restrict subtalar joint pronation, prolonging external tibial rotation (which may lead to genu varum) and decreasing shock absorption
- inappropriate running shoes which allow excessive pronation in runners predisposed to this problem
- excessive running on the crown of the road or on banked surfaces with the involved leg on the low side
- increasing mileage too quickly leading to muscle fatigue and poor form.
Those presenting at the clinic for treatment report discomfort at the outer aspect of the knee during running. This discomfort often varies from a dull ache to a sharp, stabbing pain. It usually begins with minor discomfort and becomes progressively worse, for example as running distance increases. Pain free walking can usually be achieved with the involved knee held straight, as logically this will prevent the forward and backward rubbing of the ITB over the bony prominence of the lateral epicondyle.
Simply resting the knee or providing local anti-inflammatory treatment is not usually enough, unless the initial symptoms were brought on by an exceptionally long or arduous run which will not be repeated upon return from injury: e.g. the recreational jogger who runs a marathon but may decide not to run such a distance again. However, for most runners it is usually vital that the underlying cause be established. If not, it is most likely that after a rest period the symptoms will return as training resumes.
In the initial phase of treatment, settling the inflamed area is the primary goal. This can usually be achieved via such modalities as ice, ultrasound and/or electrical stimulation, local or oral anti-inflammatory medication and a reduction in the activity which initially caused the problem eg running. Addressing poor training habits or structural abnormalities is also important. For example, stretching a tight iliotibial band, changing to a more appropriate pair of training shoes or running on level surfaces rather than the crown of a road.
If symptoms do not resolve, then complete rest from running is advisable. In more extreme cases then a steroid injection administered by a physician may be an option. In the very worst case scenario, where all conservative treatment possibilities have been exhausted, then surgery can be performed. This usually involves an incision made to the posterior (ie rear) fibres of the ITB to relieve the frictioning effect.
During treatment, where de-conditioning becomes a concern, then alternative pain-free training methods such as swimming or cycling may be required. Long term, after pain and inflammation have been resolved, it may be necessary to continue such exercises as ITB stretches before and after training sessions to prevent recurrence of symptoms. Further addressing the strength and flexibility of the hip musculature may also be required.
- Cavanaugh, PR: The Biomechanics of Lower Extremity Action in Distance Running. Foot Ankle 7:197,1987.
- Lindenberg, G, Pinshaw, R, and Noakes,TD: Iliotibial Band Friction Syndrome in Runners. Physician & Sports Medicine 12:118, 1984.
- Lucas, C. Iliotibial Band Friction Syndrome as Exhibited in Athletes. Journal of Athletic Training 3:27, 1992.
Glenn Lindsay is an Australian physiotherapist from Sydney, Glenn completed a diploma in Sports Science at the University of New South Wales before obtaining his degree in physiotherapy at the University of Sydney. A former triathlete and runner, he has undertaken numerous post graduate courses and has lectured physiotherapists and other health professionals both in the U.K. and in Australia. He has vast experience in treating athletes and sports people of all levels, including professional sporting teams and international athletes. Having been in the U.K. for 5 years, he worked both within the NHS and at private and corporate clinics before starting PhysiCo in 1997. He is physio for the Great Britain paralympic and able-bodied swimming team, and the Formula One Jordan Team.