Iliotibial band syndrome (ITBS) is a common cause of lateral knee pain in the active, athletic population. First described by Renne1 in 1975 as a condition affecting US Marine Corps recruits undergoing rigorous endurance training, the diagnosis of 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 symptoms in runners, with a reported incidence ranging from 1.6% to 12%.2-9 Among cyclists, ITBS accounts for 15% to 24% of all overuse injuries in similar observational investigations.3,10,11 Lateral symptoms attributed to ITBS have also been reported in competitive rowers, skiers, and athletes participating in soccer, basketball, triathlons, and field hockey.2,12–14
The etiology of ITBS is a subject of debate. Theories include friction of the iliotibial band (ITB) against the lateral femoral epicondyle during repetitive flexion and extension activities, compression of the fat and connective tissue deep to the ITB, and chronic inflammation of the ITB bursa. The diagnosis is typically made based on a characteristic patient history and physical examination, including specific tests designed to assess the ITB for tightness and contracture and to reproduce the patient's lateral symptoms. A thorough understanding of the local anatomy and biomechanics associated with ITBS can assist the managing orthopaedic surgeon in making the correct diagnosis and in formulating an appropriate treatment plan.
The ITB or iliotibial tract is a lateral thickening of the fascia latae of the thigh.15 The ITB is formed proximally at the level of the greater trochanter as a coalescence of the fascial investments of the tensor fascia latae and the gluteus maximus and gluteus medius muscles16 (Figure 1). Anatomic studies have demonstrated that the ITB is a dense fibrous connective tissue that passes distally along the thigh.15 Proximal to the knee joint, the ITB has attachments to the intermuscular septum and the supracondylar tubercle of the femur; it continues distally to insert on the Gerdy tubercle at the anterolateral aspect of the proximal tibia.16,17 It is separated from the lateral cortex of the femur, proximal to the lateral epicondyle, by a layer of fat that extends to the vastus lateralis muscle.16 At the level of the lateral femoral condyle, contact between the ITB and the underlying epicondyle and origin of the lateral collateral ligament is present, helping provide lateral stability to the knee joint.16
The function of the ITB depends on the position of the knee. With the knee in full extension to 20° to 30°of flexion, the ITB lies anterior to the lateral femoral epicondyle and serves as an active knee extensor.18 At 20° to 30° of flexion, the ITB assumes a posterior position relative to the lateral femoral epicondyle and becomes an active knee flexor18 (Figure 2).
Proposed Etiology of Iliotibial Band Syndrome
In the classic description of ITBS, repetitive knee flexion and extension cause a friction-type syndrome secondary to cyclic anterior-posterior motion of the ITB over the lateral femoral epicondyle.2,11,14,19–24 Supporters of the friction explanation report that this repetitive motion leads to inflammation of the distal ITB directly over the lateral femoral condyle. In an effort to explain the high incidence of symptomatic ITBS in distance runners, Orchard et al19 proposed that the condition arises from the ITB sliding through an “impingement zone” in the knee. This impingement zone occurs near 30° of flexion, approximating the angle of the knee at the time of foot strike or the early stance phase of running, which may explain why persons with ITBS experience the most pain immediately following foot strike.25 Runners who run uphill, downhill, and at slower paces tend to decrease their angle of knee flexion at foot strike, thereby spending more time in the impingement zone and, thus, experiencing worse ITBS symptoms.19 Compared with runners, Farrell et al10 found that cyclists spend 50% less time in the impingement zone and experience a reduction in force of 17% to 19% while in this zone, which may explain the lower prevalence of ITBS in this population.
Recent anatomic and radiologic studies have questioned the validity of the friction cause of ITBS. In a functional anatomy and radiology study using cadaver knees and patients both with and without ITBS, Fairclough et al15 reported that the anatomic constraints of the ITB prevent the possibility of cyclic anteriorposterior motion and rubbing over the lateral femoral epicondyle. Based on their results, the authors report that changing tension of the anterior and posterior fibers of the distal ITB creates an illusion of gliding over the epicondyle. Histologic examination of the tissue between the ITB and the lateral aspect of the femur identified highly vascularized and innervated adipose tissue, leading Fairclough et al15,26 to conclude that ITBS is more likely a “fascia lata compression syndrome” than a repetitive friction issue.
Inflammation of the bursa and tendon over the lateral epicondyle has been postulated as a third potential etiology of ITBS. Cadaver dissections by Ekman et al27 demonstrated a potential fluid-filled space that they referred to as an ITB bursa. This potential space between the ITB and the lateral femoral epicondyle was consistent with high signal intensity seen on the MRI scans of patients who presented clinically with ITBS. Proponents of the inflamed bursa theory of ITBS commonly cite the positive outcomes of surgical bursectomy of the sub-ITB space as supporting evidence.28
Risk Factors Associated With Iliotibial Band Syndrome
Observational studies and retrospective clinical reviews of patients with ITBS have identified several risk factors that can affect the ITB and may contribute to the development of symptoms.6,7,29 Training errors, including rapid changes in training routine, hill running, excessive striding, and increased mileage are commonly cited contributing factors.20,21 The surface of activity can also contribute to the development of ITBS in runners: running on surfaces with excessive camber can put excess strain on the lateral aspect of the knee. Downhill running tends to be worse because of the decrease in knee flexion that is present at the time of foot strike, thus increasing the forces experienced by the knee within the Orchard impingement zone.19,21
Anatomic factors that contribute to increased resting tension of the ITB and lateral knee strain include excessive genu varum, excessive internal tibial torsion, foot pronation, hip abductor weakness, and paralytic disorders.20,21,25,30 Noehren et al24 performed a biomechanical study to evaluate the anatomic variations and kinematics between female runners with ITBS and an asymptomatic control group. The authors found that increased hip adduction and knee internal rotation were associated with the presence of ITBS. Fredericson et al7 compared hip abductor strength between 24 distance runners with ITBS and 30 asymptomatic controls. These authors found that runners with ITBS had statistically significantly weaker hip abductors on the affected side compared with the unaffected side and compared with the asymptomatic controls. Grau et al31 used threedimensional kinematics to evaluate 18 runners with symptomatic ITBS compared with 18 healthy control subjects. The greatest biomechanical difference found was in the hip. Contrary to the results of Noehren et al,24 Grau et al31 reported less hip adduction in the ITBS group. They also noted a difference in hip frontal range of motion, maximum hip velocity, and maximum knee velocity.
The patient history and clinical examination are the most effective means of making the diagnosis of ITBS and determining the severity of the condition. On initial presentation, patients with ITBS report pain localizing to the lateral aspect of the knee. Patients typically localize the pain to the region of the distal ITB between the lateral femoral condyle and its insertion on the Gerdy tubercle. Early in the disease process, symptom onset usually occurs at the completion of a repetitive flexionextension exercise. As the condition worsens, pain is often experienced earlier in the athletic activity and may begin to be present at rest. Pertinent questions in the patient history include mileage run or cycled per week, condition of the person's running shoes, the presence or absence of swelling and mechanical symptoms, and aggravating/relieving factors. Characteristically, patients report an increase in symptom frequency and intensity when running outside, when running down hills, and with attempts at lengthening their stride.29
A complete knee examination is imperative in identifying ITBS and ruling out other pathologies present within the differential diagnosis of lateral knee pain (Table 1). Standing lower extremity alignment must be evaluated; the examiner should look for increased varus or valgus alignment at the knee. The knee should be examined for evidence of an effusion or soft-tissue swelling. ITBS patients often have tenderness over the distal ITB at the level of the lateral femoral epicondyle, a location approximately 3 cm proximal to the knee joint. In his initial evaluation of the condition, Renne1 described a “creak” sound, similar to rubbing your fingers on a wet balloon, and Noble20 described the sound like “wet leather” while palpating the lateral femoral epicondyle throughout knee flexion and extension. Knee range of motion should be assessed, and a complete ligamentous examination should be performed.
Three provocative tests are commonly used in the assessment of ITBS and ITB function. The Noble test is performed with the patient lying supine; beginning with the affected knee flexed at 90°, the leg is extended with direct pressure over the lateral femoral epicondyle, with reproducible pain near 30° of knee flexion.28 The Ober test can be used to assess ITB contracture and tightness. With the patient lying on his or her side with the unaffected leg down and bent at 90°, the examiner stabilizes the pelvis, then abducts and extends the affected leg, followed by an attempt by the examiner to adduct the leg. The Ober test is positive if the examiner cannot adduct the affected leg from this position.11,21 The Thomas test is used to determine 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. A positive test results if the patient cannot completely extend and lower the affected leg to horizontal.32
Although not routinely required, radiographic imaging can be used to supplement the physical examination. Routine radiographs of the knee, including AP, lateral, and sunrise views, can be used as a diagnostic adjunct to rule out other possible causes of lateral knee pain, such as lateral joint space narrowing from degenerative disease, patellar maltracking, and stress fractures. However, in a study comparing the radiographs of 16 knees with ITBS symptoms and 16 age- and sexmatched unaffected knees, no difference in radiographic findings was reported.1
In cases of refractory ITBS, MRI can be used as a diagnostic tool. Ekman et al27 described a case series of 7 patients with a clinical diagnosis of ITBS compared with 10 age- and sex-matched unaffected knees. These authors reported the presence of a high-intensity signal, representing a fluid-filled collection, over the lateral epicondyle deep to the ITB, as well as a marked thickening of the distal ITB (Figure 3). MRI can also be useful in ruling out other potential causes of lateral knee pain, including articular cartilage injuries, meniscal tears, and cysts.
Ultrasonography may help in the management of ITBS. Gyaran et al33 performed a study to measure ITB thickness with ultrasonography. They recommended the use of ultrasonography in following up patients with the diagnosis of ITBS because of the low cost and availability of this modality compared with MRI.
Nonsurgical management is the mainstay of treatment of symptomatic ITBS.2 As with most orthopaedic conditions, activity modification can improve the pain associated with this syndrome. Rest from the inciting activity, such as running or cycling, until pain has resolved, followed by a gradual return to activity as tolerated, may help to avoid symptom recurrence. Equipment modification, such as altering cleat position or lowering the bicycle seat and raising the handlebars in cycling, may also decrease pain and allow for a return to activity.23
Oral nonsteroidal anti-inflammatory drugs (NSAIDs) and/or corticosteroid injections can be used to reduce the acute inflammatory response. NSAIDs alone have not been found to be effective in providing symptom relief; however, several studies have shown that NSAIDs, in conjunction with other nonsurgical modalities, can be beneficial.3 Local corticosteroid injections can relieve pain as well as aid in the diagnosis of ITBS. In a randomized controlled trial of 18 individuals with clinical ITBS, Gunter and Schwellnus34 reported statistically significantly better pain relief in the experimental group (1 mL 1% lidocaine plus 1 mL methylprednisolone) compared with control subjects (2 mL 1% lidocaine) by the second week postinjection.
Physical therapy is an important component of the nonsurgical management of ITBS. Typical regimens consist of specific stretching exercises focused on the ITB, tensor fascia latae, and gluteus medius (Figure 4). In a biomechanical study that examined the effectiveness of three different ITB-specific stretches in five elite distance runners, Fredericson et al35 demonstrated that all three stretching methods lead to statistically significant lengthening of the ITB relative to baseline measurements. Manual therapy that consists of softtissue and medial patella mobilizations may also contribute to lengthening the ITB. Graston and active release soft-tissue mobilization techniques have been gaining popularity, but research on these treatments is limited (Figure 5).
Additionally, the patient can use a foam roller as a myofascial release tool to break up soft-tissue adhesions in the ITB (Figure 6). Once the patient is capable of performing the stretching regimen without pain, strengthening is added to the rehabilitation program.2 Attention is paid to proximal strengthening of the hip abductors (gluteus medius) and the core muscles to stabilize the pelvis to prevent excessive adduction of the hip. Modalities such as cryotherapy may also be incorporated into the physical therapy program in an effort to reduce the inflammatory component of the condition. Increasing neuromuscular control can also be a goal of physical therapy through several multidimensional movement patterns, eccentric muscle contractions, and integrated movement patterns.32,36 Education about proper running form and running progression are important in getting patients back to their goals. Biomechanical studies have shown that faster-paced running is less likely to aggravate the ITB; faster strides are initially recommended over slow jogging.36
Foot orthoses are also a potential nonsurgical intervention for ITBS.21 Although no specific evidence supports the use of orthoses, theoretically, an orthosis used to raise the heel in runners may decrease the flexion angle of the knee at foot strike and may decrease symptoms.19
A systematic review performed by Ellis et al3 to evaluate the nonsurgical management of ITBS included four randomized trials that used NSAIDs, deep-tissue massage, phonophoresis, immobilization, and corticosteroid injections. The authors concluded that limited evidence exists to support nonsurgical management; however, the studies were heterogenous and of insufficient quality. Despite the lack of evidence supporting a particular management option, most patients have symptomatic relief without surgery within 6 to 8 weeks and are capable of returning to their athletic activities with no long-term sequelae.2
Most patients with symptomatic ITBS respond to nonsurgical management, but refractory cases exist. We typically reserve surgical intervention for patients who continue to be symptomatic and functionally limited for >6 months despite an adequate trial of oral NSAIDs, focused physical therapy, and a corticosteroid injection. We have found that patients who experience temporary symptom resolution following a corticosteroid injection respond best to surgical intervention. In refractory cases of ITBS, surgical management can be indicated with several different surgical techniques (Figure 7). Secondary to the rare need for surgical intervention, outcome data following these procedures are limited.
One surgical treatment option is the percutaneous release of the ITB, which is performed with the knee held at 90° of flexion so that the posterior fibers of the ITB are free from the lateral femoral epicondyle. A small percutaneous incision is made to release the ITB under local anesthesia.11 Outcome data following this technique are very limited. Holmes et al11 reported that, of four patients treated percutaneously, three later required formal open ITB release.
Open surgical release entails excising a portion of the ITB from directly over the lateral epicondyle. Noble20 described this procedure with an incision over the posterior 2 cm of the ITB overlying the lateral femoral epicondyle. He created a V-shaped incision in the ITB at this level to release it.20 Martens et al37 described a similar technique in which the knee is held at 30° of flexion while a triangular portion of the ITB, 2 cm wide at the posterior base and 1.5 cm in height, is resected from the posterior portion of the ITB that lies over the lateral femoral epicondyle. In their series of 19 treated patients, these authors reported successful outcomes, with all patients returning to their previous athletic activities, without limitation, by a mean of 7 weeks. Holmes et al11 detailed a similar resection of the ITB but in the shape of an ellipse posteriorly, approximately 2 cm in length at the apex, and 4 cm at the base of the condyle. In their series of 21 cyclists treated in this manner, Holmes et al11 reported a successful return by 17 (81%) of the patients to their preoperative cycling level by 6 to 8 weeks. In a retrospective review of 45 patients treated with an open elliptical release of the posterior ITB, Drogset et al38 reported good to excellent results in 85% of the patients at the time of final follow-up (average, 25 months).
ITB Z-lengthening is also an option. As described by Richards et al,39 the Z-lengthening is performed through a 5-cm oblique incision made overlying the distal ITB. Once the ITB is exposed, two transverse incisions are made halfway across its width at the proximal and distal extents of the area to be lengthened. These transverse incisions are connected with a longitudinal incision, allowing the limbs of the Z-plasty to slide past each other. The ITB is then repaired in a lengthened position; typically, 1.5 cm in length is gained (Figure 8). In a retrospective review of eight patients treated with ITB Z-lengthening followed for a mean of 76 months postoperatively, Barber et al40 reported successful results; all eight patients had complete symptom resolution and full return to their preoperative activity level by 8 weeks.
An open ITB bursectomy has also been described to manage recalcitrant ITBS. The bursa underlying the ITB is removed, and the ITB itself is left intact. In a series of 12 consecutive patients treated with this technique, Hariri et al28 reported positive [results, with statistically significantly decreased visual analog scores and a return to preinjury activity levels. Six patients in this series were completely satisfied with their outcomes, three were mostly satisfied, and two were somewhat satisfied.
Recently, Michels et al41 described an arthroscopic technique to treat refractory ITBS. Following their hypothesis that ITBS occurs secondary to inflammation localized to the fibrous attachments of the ITB to the femur and the surrounding fat, the authors used a synovial shaver to resect the lateral synovial recess accessed through an accessory superolateral portal. In their series of 33 patients followed for a mean of 28 months, good to excellent results were reported in 97%. All treated patients in this series were able to return to full athletic activity. Although continued study is necessary, the arthroscopic management of refractory ITBS via débridement and resection of the lateral synovial recess appears to be promising as a minimally invasive means to symptom relief and successful return to athletics.
ITBS is a common cause of lateral knee pain in the athletic patient population. A thorough understanding of the associated anatomy, and specific history and physical examination findings, enable the treating orthopaedic surgeon to make the appropriate diagnosis and formulate a treatment plan. Despite a lack of consensus on the exact etiology underlying the condition and limited scientific data to support current treatment algorithms used, most patients with ITBS improve with activity modification and nonsurgical management. In cases of refractory disease, a variety of surgical management options is available, with good results reported. As ITBS increases in prevalence, continued study is necessary to maximize treatment outcomes and return patients to painfree athletic activity.
Evidence-based Medicine: Levels of evidence are listed in the table of contents. In this article, reference 34 is a level II study. References 3, 6-8, 13, 24, and 30 are level III studies.
References 1, 4, 5, 9-11, 16, 19, 20, 25, 27, 28, 31, and 37-41 are level IV studies. References 2, 12, 14, 15, 17, 22, 23, 26, 29, 32, 33, 35, and 36 are level V expert opinion.
References printed in bold type are those published within the past 5 years.
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