Iliotibial Band Syndrome

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Iliotibial Band Syndrome

The knee is the most common site of injury among runners, but due to the repetitive stress placed on the joint, knee injuries are also frequently observed in cyclists, soccer players, skiers, rowers, and weightlifters.

Iliotibial Band Syndrome (ITBS) is a common overuse injury, particularly among runners and cyclists. It is characterized by pain and tenderness localized over the lateral femoral condyle and, in some cases, the greater trochanter. ITBS accounts for approximately 12% of all overuse injuries in runners and is prevalent in sports that involve significant running components.

The hallmark symptom of ITBS is pain aggravated by activity, especially when the knee is at around 30° of flexion, a point where the iliotibial band passes over the lateral femoral epicondyle, causing friction. Repetitive knee flexion activities, such as running, cycling, or squatting, typically worsen symptoms.

The iliotibial band (ITB) is an extension of the tensor fascia lata (TFL) muscle’s tendinous portion, with additional contributions from the gluteus maximus and gluteus medius muscles. Proximally, it attaches to the iliac crest and runs down the lateral thigh, where it is anchored to the linea aspera of the femur via the intermuscular septum. As the ITB descends, it passes over the lateral femoral epicondyle, and distally, it inserts into the tibia at Gerdy’s tubercle. The ITB also connects to the lateral femoral condyle and the patella, assisting in the stabilization of the knee joint during dynamic movements.

The primary function of the ITB is to provide lateral stability to the knee and to distribute muscle forces efficiently during activities that involve repetitive leg motion, such as running and cycling. Additionally, the ITB plays a role in hip abduction, as well as internal and external rotation of the hip. It also assists in knee flexion and extension, especially during the transition between these movements, helping maintain proper alignment and stability of the lower extremities throughout the gait cycle.

The etiology of Iliotibial Band Syndrome (ITBS) is multifactorial, involving a combination of anatomical, biomechanical, and training-related factors. Traditionally, it was believed that ITBS results from repetitive friction between the iliotibial band (ITB) and the lateral femoral epicondyle during knee flexion and extension cycles, leading to irritation. This theory, often called “Iliotibial Band Friction Syndrome,” suggests that the ITB shifts back and forth over the epicondyle, causing inflammation.

However, more recent research challenges this friction model. Studies now suggest that ITBS arises from the compression of a highly innervated fatty connective tissue layer between the ITB and the lateral epicondyle. This repeated compression, rather than friction, is considered the primary source of pain.

Patients with ITBS typically report focal pain over the lateral femoral condyle, which worsens during physical activity. Some individuals may also experience pain radiating to the lateral hip or present solely with hip pain. A snapping or popping sensation over the lateral knee with movement may also be reported.

The incidence of Iliotibial Band Syndrome is increased in the presence of asymmetry in the length of the lower extremities, pelvic tilt, and individuals with a genu varum deformity. In addition, runners’ training conditions may also play a role, with uneven or cambered surfaces believed to be provocative factors.

Contributing Factors

The likelihood of developing ITBS increases with lower extremity asymmetries or biomechanical abnormalities, such as:

• Leg length discrepancies
• Pelvic tilt
• Genu varum (bowed legs)
• Additionally, training factors such as running on uneven surfaces or cambered roads can provoke symptoms, especially in athletes.

Risk Factors

• Tight iliotibial band
• Leg length inequality
• Genu varum (bow-legged alignment)
• Prolonged running or walking
• Interval or high-intensity training
• Weakness of the knee extensors, flexors, or hip abductors

Differential Diagnosis for Lateral Knee Pain

Patients presenting with lateral knee pain may be suffering from several conditions. The differential diagnosis includes the following:

• Iliotibial Band Syndrome (ITBS)
• Lateral Collateral Ligament (LCL) Sprain or Tear
• Lateral Meniscus Tear
• Fibular Head Dysfunction
• Vastus Lateralis Myofascial Pain Syndrome
• Osteoarthritis of the Knee
• Biceps Femoris Tendinopathy or Strain
• Popliteus Tendinopathy
• Referred Pain from Hip or Lumbar Spine Pathology

• Gradual onset of lateral knee pain that progresses to a sharp or burning sensation.
• Pain worsens during activities such as running downhill, lengthening stride while running, descending stairs, or sitting with knees flexed for prolonged periods (e.g., during travel).
• Initially, pain occurs after activity or a few minutes into it; however, as the condition progresses, pain appears earlier or may even persist at rest.
• A snapping sensation on the outside of the knee may be experienced by some individuals, often indicating iliotibial band involvement.

• Localized tenderness over the distal iliotibial band, especially when the knee is flexed to 30 degrees, maximizes tension on the band.
• Mild swelling may be observed along the distal iliotibial band or near the lateral femoral epicondyle.
• Positive Noble Compression and Ober tests.

Iliotibial Band Syndrome is usually a clinical diagnosis. MRI is the preferred imaging modality for ITBS, revealing thickening of the ITB and mild edema at the lateral femoral epicondyle. However, MRI may be used to help rule out other causes of lateral knee pain, such as meniscal tears, lateral collateral ligament injury, or bursitis. Diagnostic ultrasound can also detect ITB thickening, especially in chronic cases.

The following are examples of red flags for patients presenting with knee pain:

• A history of significant injury
• Severe pain
• Unrelenting pain
• Nocturnal pain
• Unexplained weight loss
• Fever
• Deformity
• Significant swelling
• Presence of tingling, numbness, burning, or other neurological impairment
• Significant loss of range of motion
• Severe tenderness on palpation or severe pain with any examination procedure

If any red flags are identified during history taking and clinical examination, referral for urgent medical evaluation and further investigation is warranted.

Common Causes of Lateral Knee Pain

Iliotibial Band Syndrome

• Key Findings on Clinical Presentation: Pain and tenderness just above the lateral knee joint that worsens with repetitive knee bending. It is commonly seen in runners and cyclists.
• Special Tests: Positive Ober and Noble Compression tests.

Lateral Meniscus Injury

• Key Findings on Clinical Presentation: Lateral knee pain that occurs with twisting movements, together with joint line tenderness and occasional clicking or locking.
• Special Tests: Positive McMurray, Apley’s Compression, and Thessaly tests.

Lateral Collateral Ligament Injury

• Key Findings on Clinical Presentation: Lateral knee pain and tenderness along the lateral collateral ligament, together with knee instability, especially during side-to-side movements.
• Special Tests: Positive Varus Stress test.

Biceps Femoris Tendinopathy

• Key Findings on Clinical Presentation: Lateral knee pain at the attachment of the biceps femoris tendon to the fibular head. Often seen in athletes who engage in repetitive sprints or sudden stops. Pain on resisted knee flexion.

Vastus Lateralis Myofascial Pain Syndrome

In patients presenting with lateral knee pain, a complete clinical examination should include an evaluation for myofascial pain syndrome as either the primary cause of the pain or as a concomitant condition. The primary muscle to evaluate is the vastus lateralis. The trigger points associated with myofascial pain syndrome may be located anywhere within a muscle and its fascia. Therefore, the entire muscle should be examined thoroughly. However, based on our clinical experience, the common locations for trigger points in the vastus lateralis causing lateral knee pain are presented below: