Iliotibial Band Syndrome
Anatomy
The ITB is a thickened part of the tensor fascia lata, and has some contribution from fibres of the gluteal muscles. It it connected to the linea aspera by an the intermuscular septum and to the supracondylar region of the femur by course fibrous bands. It inserts on the lateral border of the patella, the lateral retinaculum, and Gerdy's tubercle.
One view is that ITB function depends on knee position. Between full extension to 20-30° of flexion the ITB is anterior to the lateral femoral epicondyle, and so functions as an active knee extensor. At 20-30° of flexion of flexion the ITB sits posterior to the lateral femoral epicondyle and functions as an active knee flexor.[1]
However another view is that the ITB functions to tense the fascial envelope around the thigh to promote optimal muscle function. The connection between the lateral femoral distal part of the ITB (from lateral epicondyle to Gerdy's tubercle) is actually a ligament, and the proximal part (associated with TFL and gluteus maximus) is the tendinous portion. The tendinous portion therefore doesn't cross the knee and so can't have any action on the knee joint.[2]
Epidemiology
ITBS is common in athletes, and the most common cause of lateral knee pain in this population.
Pathophysiology
The traditional theory relates to friction in that ITBS is caused by excessive friction of the distal ITB and/or its associated bursa as it glides over the lateral femoral epicondyle with repeated flexion-extension cycles of the knee.
An alternative theory relates to compression. In this theory ITBS is caused by increased compression of a highly vascularised and innervated layer of fat and loose connective tissue separating the ITB from the femoral epicondyle. Proponents suggest that the underlying cause is impaired hip muscle function.[2]
Clinical Features
History
Iliotibial band syndrome usually presents at pain over the lateral aspect of the knee, but occasionally can become irritated proximally and present as hip pain. In the lateral knee the pain is usually located over the lateral femoral epicondyle, but this may radiate distally to Gerdy's tubercle, or proximally to the tensor fascia lata.
Common aggravating activities are those that involve repetitive flexion and extension cycles of the knee such as running and cycling, and the pain usually starts within several minutes. There is often aggravation with activity on inclined surfaces such as downhill running. The posterior fibres of the ITB are in contact with the lateral femoral epicondyle at approximately 20° to 30° of knee flexion, and during downhill running there is a reduced knee flexion angle upon foot strike, leading to the ITB fibres being in more frequent contact with the lateral femoral epicondyle. ITBS is less common in sprinters because their knees have a higher degree of flexion at foot strike.
The pain is usually diffuse initially over the whole lateral knee. The pain usually eventually localises to an area 2 to 4cm proximal to the lateral joint line.
Pain can eventually become constant even at rest with continued aggravation.
Examination
In some cases the patient may have a stiff-legged gait due to avoidance of knee flexion.
There is tenderness over the lateral femoral epicondyle.
Pain can be provoked by single-leg stance with knee flexion to 30°
There may be tightness with the Ober test.
Look for biomechanical variations. There may be a leg length discrepancy with ITBS occurring in the shorter leg. Forefoot varus and high knee Q angles are also associated features.
Imaging
Ultrasound allows dynamic imaging of the motion of the ITB with flexion and extension
MRI can be useful when the diagnosis is in question and to exclude other pathologies.
In the knee typical MRI findings are ITB thickening, and fluid collection deep to the ITB.
In the hip there are similar soft tissue changes but there may also be associated tendinopathies of the gluteus medius and minimus tendons, as well as marrow oedema in the affected bone.
There may be primary or secondary (adventitious) bursae. A bursa may be confused with a normal lateral recess.
Differential Diagnosis
- Lateral meniscus tear
- Posterolateral corner injury
- Patellar dislocation or subluxation
- Lateral collateral ligament tear
- Iliotibial Band Syndrome
- Osteoarthritis exacerbation
- Osteochondral lesion lateral femoral condyle
- Popliteus Tendinopathy
- Biceps Femoris Tendinoapthy
- Semimembranosus Tendinopathy/bursitis
- Fibula head fracture
- Proximal Tibiofibular Joint Instability
- Snapping Biceps Femoris and Popliteus Tendons
- Peroneal Nerve Compression/Neuritis
Treatment
In the acute phase provocative activities should be avoided.
Corticosteroid injections can be used to reduce inflammation, and is usually injected where the ITB crosses the lateral femoral condyle. The addition of local anaesthetic can provide diagnostic value.
Stretching is sometimes recommended once the acute inflammation has settled, however many argue that the ITB cannot be stretched because of its numerous attachments.
In the subacute phase biomechanical abnormalities should be addressed. Assess for tightness in the ITB, hamstring, gluteal, and adductor muscles.
Strengthening is recommended after range of motion has improved. Here the hip abductors are focused on.
Surgery is very uncommon. Approaches involve resection and incisions of the ITB to reduce tension and minimise bony contact.
Further Reading
References
- ↑ 1.0 1.1 Strauss EJ, Kim S, Calcei JG, Park D. Iliotibial band syndrome: evaluation and management. J Am Acad Orthop Surg. 2011 Dec;19(12):728-36. doi: 10.5435/00124635-201112000-00003. PMID: 22134205.
- ↑ 2.0 2.1 Fairclough J, Hayashi K, Toumi H, Lyons K, Bydder G, Phillips N, Best TM, Benjamin M. Is iliotibial band syndrome really a friction syndrome? J Sci Med Sport. 2007 Apr;10(2):74-6; discussion 77-8. doi: 10.1016/j.jsams.2006.05.017. Epub 2006 Sep 22. PMID: 16996312.
- ↑ Ellis R, Hing W, Reid D. Iliotibial band friction syndrome--a systematic review. Man Ther. 2007 Aug;12(3):200-8. doi: 10.1016/j.math.2006.08.004. Epub 2007 Jan 8. PMID: 17208506.
