1
Background
Iliotibial band syndrome (ITBS) is a common cause of lateral knee pain in athletes. This syndrome was first described in 1975 as a condition affecting US Marine recruits, who undergo rigorous endurance training [ ]. The number of cases diagnosed with ITBS has increased with the growing popularity of recreational distance running and cycling. Epidemiologic studies have identified ITBS as the most common cause of lateral knee pain in runners. Its incidence has been reported to range from 1.6% to 12% [ , ]. Among cyclists, ITBS is held responsible for 15%–24% of all overuse injuries [ ]. ITBS symptoms have also been reported in competitive rowers, skiers, and athletes participating in soccer, basketball, triathlons, and field hockey [ ].
Patients with ITBS may also present with a lateral snapping hip. This sign is related to the ITB rapidly passing anteriorly over the greater femoral trochanter. Athletes sometimes report an audible painful snap on landing from a jump [ ].
The etiology of ITBS is still not clearly defined. Suggested theories include:
- –
Compression of the fat and connective tissue deep to the ITB.
- –
Chronic inflammation of the iliotibial bursa.
- –
Friction of the ITB against the lateral femoral epicondyle during repetitive flexion and extension activities ( Fig. 4.1 ).
Fig. 4.1
Anatomy of the iliotibial band, which can cause snapping as it slips anteriorly and posteriorly over the prominent greater trochanter and lateral femoral condyle.
The diagnosis is typically made based on patient history and physical examination with specific tests to assess the ITB for tightness and to reproduce the patient’s symptoms.
Several risk factors have been identified. Training errors, including rapid changes in training routine, hill running, and increased distances are commonly cited [ , ]. The surface of activity can also contribute to the development of ITBS in runners, as running on inclined surfaces can put excessive stress on the lateral compartment of the knee. Downhill running tends to be worse because of the decrease in knee flexion at the time of foot strike increasing the forces exerted on the knee [ , ].
The anatomic factors that contribute to increased tension of the ITB and lateral knee strain include excessive genu varum, excessive internal tibial rotation, foot pronation, hip abductor weakness, and paralytic disorders which result in muscle imbalance [ ].
2
Synonym
Iliotibial band friction syndrome.
Runner’s knee.
Iliotibial tract friction syndrome.
Snapping knee.
3
Clinical Study
3.1
Symptoms
On initial consultation, patients with ITBS usually report pain situated on the lateral aspect of the knee. Typically, they localize the pain precisely in the region of the distal ITB, between the lateral femoral condyle and its insertion on the Gerdy tubercle ( Fig. 4.2 ).
In the early stages of the disease, the symptoms usually occur at the completion of a repetitive flexion-extension exercise. As the condition worsens, pain is often experienced earlier in the athletic activity and may be present at rest.
Questions about the patient’s history include the distance run or cycled per week, condition of the athlete’s running shoes, the presence of swelling, and mechanical symptoms and aggravating/relieving factors. The patients usually report an increase in symptom frequency and intensity when running outside, when running down hills, and when increasing stride length [ ].
3.2
Physical Examination
A complete knee examination is imperative in order to identify ITBS and to rule out other pathologies representing the differential diagnosis of lateral knee pain.
Static lower extremity alignment must be evaluated. The examiner should look for varus of the knee which increases the ITB tension.
The knee should be examined for evidence of an effusion or soft-tissue swelling.
ITBS patients often present with tenderness at the level of the lateral femoral condyle, approximately 3 cm proximal to the knee joint.
While palpating the lateral femoral epicondyle throughout knee flexion and extension, Renne [ ] described a sound similar to rubbing fingers on a wet balloon and Noble [ ] described the sound like wet leather.
A complete ligament examination should be performed and knee range of motion (ROM) should be assessed and typically no abnormalities should be found.
Four tests are commonly used in the assessment of ITB function and ITBS diagnosis.
3.2.1
Renne’s test
While standing on the involved side, the patient is instructed to place one hand on the examiner’s shoulder for balance and slowly squat (one legged) to 60–90 degrees flexion and then rise back up. The test is considered positive if it reproduces the patient’s pain ( Fig. 4.3 ).
3.2.2
The Noble test
This test is performed with the patient lying supine, beginning with the affected knee flexed at 90 degrees and the leg is extended with direct pressure over the lateral femoral epicondyle. The test is positive when pain is reproducible near 30 degrees of knee flexion [ ] ( Fig. 4.4 ).
3.2.3
The Ober test
The Ober test can be used to assess ITB tightness. With the patient lying on his side with the unaffected leg down and bent at 90 degrees, the examiner stabilizes the pelvis, then abducts and extends the affected leg. Then, the examiner tries to adduct the leg. The Ober test is positive when the examiner cannot adduct the affected leg from this position [ ] ( Fig. 4.5 ).
3.2.4
The Thomas test
This test is used to evaluate the tightness of the iliopsoas muscle, rectus femoris muscle, and ITB. The patient is instructed to lie supine at the edge of the examination table with both knees held to the chest. While the examiner stabilizes the pelvis, the patient holds the unaffected leg to the chest, and the affected leg is extended and lowered. The test is considered positive when the patient cannot completely extend and lower the affected leg horizontally [ ] ( Fig. 4.6 ).
