Anatomy
The Iliotibial band (ITB) is a thick band of fascia that runs down the outside of your thigh. At the top of your thigh it is formed by the Tensor Fascia Latae (TFL) muscle, and Gluteus Maximus and at the bottom it acts like a lateral ligament attaching to the lateral femoral condyle (the outer part of your thigh bone) and patella (kneecap) before connecting to the outside of your tibia (shin bone). This demonstrates the ITB's role in lateral stability and how closely related the hip and the knee are.
How does it feel?
ITB Syndrome (ITBS) is a common injury affecting the outside of the knee and causing pain with activity.
Common symptoms include:
Sharp pain on the outside of the knee
Pain worsens with continuous running, coming down stairs or repetitive activities involving bending of the knee
Swelling on the outside of the knee
Pain during bending of the knee
How common is it?
ITBS is one of the most common injuries in runners presenting with lateral knee pain, with an incidence of up to 22% of all overuse injuries. In cycling ITBS accounts for 15% to 24% of overuse injuries. The prevalence of ITBS in women is estimated to be between 16% and 50% and for men between 50% and 81%.
Causes
There are many proposed mechanisms of ITBS. A common theory is, when the knee moves from full extension (straight leg position) into/past 20° of flexion (bending), the ITB switches from being an extensor to a flexor, as it moves past the underlying lateral femoral epicondyle. And as such, this friction between the ITB and lateral femoral epicondyle is thought to cause irritation to the tendon, potentially the bursa, and result in local inflammation.
Therefore, activities with repetitive flexion and extension of the knee can cause the iliotibial band to rub repeatedly along the lateral femoral epicondyle producing irritation. Long distance runners and cyclers are therefore at greater risk to develop ITBS.
Muscle weakness of the hip abductors (muscles on the inside of the leg) are also commonly linked with ITBS as this causes increased hip internal rotation (inward rotation of the leg) and knee adduction (bringing knees closer together), resulting in greater compressive forces.
Weakness and fatigue of the knee flexors (front of thigh) and extensors (back of thigh) can also cause decrease forces with braking movements, putting more strain on the ITB to stabilise the leg.
Other proposed causes for ITB syndrome include compression of the highly sensitive fat pad and connective tissue that is deep to the IT band, as well as chronic inflammation of the IT band bursa.
Risk factors
Modifiable risk factors include
running on uneven surfaces,
hill running,
poor running and training technique,
and abrupt changes in training intensity, such as increases in running distance.
Anatomical factors include:
Internal tibial torsion (inward rolling of knees and hip),
weak hip muscles,
excessive foot pronation (rolling in),
and medial compartment arthritis leading to genu varum (bowing out of knee) can increase the tension of the ITB
What else could it be?
Other causes of lateral knee pain:
Stress fracture of the lateral tibial plateau
Lateral meniscus tear
Osteoarthritis
Lateral collateral ligament strain
Biceps femoris tendinopathy
Patellofemoral syndrome
Recovery prognosis
Roughly 50 to 90% of patient will improve within 4 to 8 weeks when managed conservatively, without surgery. However, surgical interventions also report good to excellent results. ITBS typically follows a fluctuating course and may relapse at any point in the treatment progression or return to activity.
How to get better?
Treatment typically involves:
Addressing tightness of the gluteal muscles and TFL are commonly associated with ITBS.
Gluteal trigger point, dry needling and stretching are commonly used to reduce the tension and relieve local pressure of the ITB around the LFE.
Strengthening of the hip external rotators and abductors is also an important component of the treatment to correct the underlying weakness and improve the endurance of these muscles.
In severe cases where conservative management fails, surgery may be an option to decompress/release the ITB, as well as removal of abnormal tissue either at the knee of the hip.
Recent research:
Hip strengthening exercises are shown to be superior to ITB stretching in reducing pain, and improving strength and function.
Decreasing hip flexion, adduction angle and abductor moment may be a reasonable strategy to avoid the occurrence of ITBS.
Shoe modification, foot orthosis, and sport specific technique training can help prevent ITBS from returning in some cases.
Recovery plan:
Most patients will have complete symptom relief and able to return to activity within 6 to 8 weeks with nonoperative management alone.
The recommended progression back to activity starts with a week of running on alternating days on a flat surface.
The following weeks are focused on fast-paced running daily and avoid downhill running.
After 3 to 4 weeks, the patient can gradually increase the distance and frequency. Introducing hills and cambered surfaces should only take place if there is no pain or symptoms on a flat surface.
If the patient relapses, then they will need to start their activity progression over again and may require a period of rest beforehand
Conclusion/Summary
Highly prevalent condition affecting predominantly runners
Etiology isn’t 100% clear but may not be as simple is the ITB gliding over the lateral femoral epicondyle causing repetitive friction.
Important not to only focus on saggital movements at the knee but adopt a multi-planar approach and incorporate analysis of the hip and ankle
Prognosis is good with up to 90% improving with conservative management over 4-8 weeks.
References
Brown, A. M., Zifchock, R. A., Lenhoff, M., Song, J., & Hillstrom, H. J. (2019). Hip muscle response to a fatiguing run in females with iliotibial band syndrome. Human movement science, 64, 181-190.
Charles, D., & Rodgers, C. (2020). A literature review and clinical commentary on the development of Iliotibial Band Syndrome in runners. International journal of sports physical therapy, 15(3), 460.
Pegrum, J., Self, A., & Hall, N. (2019). Iliotibial band syndrome. Bmj, 364.
Van der Worp, M. P., van der Horst, N., de Wijer, A., Backx, F. J., & Nijhuis-van der Sanden, M. W. (2012). Iliotibial band syndrome in runners. Sports medicine, 42(11), 969-992.