You are in: eMedicine Specialties > Orthopedic Surgery > KNEE Iliotibial Band Friction SyndromeArticle Last Updated: Jun 1, 2005AUTHOR AND EDITOR INFORMATIONAuthor: Steven Karageanes, DO, Director, Primary Care Sports Medicine Fellowship, Director, Sports Medicine Education, Center for Orthopedics and Neuroscience; Department of Medical Education, Oakwood Healthcare System Steven Karageanes is a member of the following medical societies: American Medical Association, American Osteopathic Association, and Michigan State Medical Society Coauthor(s): Cynthia Kooima, MD, Staff Physician, Department of Orthopedic Surgery, Henry Ford Hospital; Terrence Lock, MD, Senior Consulting Surgeon, Department of Orthopedic Surgery, Henry Ford Hospital Editors: Dennis P Grogan, MD, Clinical Professor, Department of Orthopedic Surgery, University of South Florida College of Medicine; Chief of Staff, Department of Orthopedic Surgery, Shriners Hospital for Children of Tampa; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Thomas M DeBerardino, MD, Director, John A Feagin, Jr Sports Medicine Fellowship at West Point, Clinical Instructor in Surgery, Orthopedic Surgery Service, Keller Army Community Hospital at West Point; Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital; Carlos J Lavernia, MD, FAAOS, Adjunct Clinical Professor, Department of Orthopedic Surgery, University of Miami School of Medicine; Medical Director, Orthopedic Institute at Mercy Hospital Author and Editor Disclosure Synonyms and related keywords: ITBFS, iliotibial band syndrome, jogger's knee, knee pain, knee injury INTRODUCTIONIliotibial band friction syndrome (ITBFS) is a common cause of lateral knee pain, particularly among runners, military personnel, and cyclists. It is considered an overuse syndrome that usually is treated successfully with a conservative approach. Biomechanical and training factors play a large role in the development of ITBFS, but its exact etiology is somewhat elusive. Conservative therapy is successful in most persons with ITBFS. When conservative therapy does not resolve the pain, surgery may be indicated. Conservative therapy should be employed for 3 months before surgery, but most patients for whom surgery is necessary have had symptoms for more than 9 months. Surgery is rarely indicated, but the most common procedure for ITBFS is resection of the posterior portion of the iliotibial band (ITB) and, if desired, the adventitial bursa deep to the band. Surgery is performed with the knee held in 30° of flexion and consists of a limited resection of a small triangular or elliptical piece of the posterior part of the ITB covering the lateral femoral epicondyle. The bursa may be removed in certain cases as well. ProblemITBFS typically is observed in people who exercise vigorously. The overuse creates stress that the body cannot repair, and soft tissue breakdown occurs. When the knee flexes, the ITB moves posteriorly along the lateral femoral epicondyle. Contact against the condyle is highest between 20° and 30° (average 21°), so when the band is excessively tight or stressed, the ITB rubs more vigorously. The space deep to the ITB is believed to have an adventitial bursal extension from the synovial capsule. This space was coined the lateral synovial recess (LSR). The LSR lies underneath the ITB and acts as an interface between the ITB and the lateral femoral epicondyle. In runners, friction occurs near or just after foot strike during the contact phase of the gait cycle. Downhill running reduces the knee flexion angle and can aggravate ITBFS, while sprinting and fast running increase the knee flexion angle and are less likely to cause the syndrome. FrequencyOverall incidence of ITBFS in the general population is not well reported. Depending on which population is examined, the incidence ranges from 1.6-52%. Incidence varies with the target population's type and intensity of activity. For instance, Linenger et al reported that in 12 weeks of Marine basic training, ITBFS was the most common specific injury and accounted for 22.2% of all lower extremity injuries. Runners experience 12% of all running-related overuse injuries from ITBFS. EtiologyThe etiology of ITBFS is multifactorial. Many factors have been postulated, few with overwhelming evidence supporting them. ITBFS usually is caused by overuse, mostly due to errors in training. Single session errors cause ITBFS as often as repetitive deficiencies. Sudden changes in surface (ie, soft to hard, flat to uneven or decline), speed, distance, shoes, and frequency can break down the body faster than it can heal, causing injury. Other factors frequently reported are the following:
Studies examining limb length discrepancies provide conflicting conclusions regarding whether a direct correlation exists. Limb length inequalities cause changes in hip abduction during the gait cycle, sacral leveling, and pelvic tilt, which is believed to increase tension on the ITB and tensor fascia lata. However, other studies did not find a direct correlation between limb length inequality and ITBFS. Still, the postulate merits consideration when examining the hip and pelvis. Genu varum is considered a risk factor due to the increased tension on the ITB as it is stretched more over the lateral femoral epicondyle. This concept is widely accepted, though with little empirical support. Overpronation is controversial as well. In the running cycle, the lower limb strikes the ground with a rigid supinated foot. As the leg moves forward, the tibia internally rotates over the planted foot, "unlocking" it into a pronated-everted position, which allows for weightbearing. Pronation and internal rotation stress the ITB. Excessive pronation causes quicker tibial internal rotation and increased hip adduction, stressing the ITB over the lateral femoral condyle. James implicated a combination of genu varum, heel varus, forefoot supination, and compensatory pronation with ITBFS, but further videography studies led to dispute of that claim. Most studies support overpronation as a potential cause. Hip abductor weakness is an important factor as well. Several studies support this claim. When the foot strikes the ground, the femur adducts against the eccentric load of the abductors (gluteus medius and tensor fascia lata). These muscles move from eccentric to concentric through the support phase and into the propulsive phase of gait. The gluteus medius also externally rotates the hip, while the tensor fascia lata internally rotates. When the hip abductors are weakened or fatigued, runners have increased adduction and internal rotation at midstance. This generates more valgus force at the knee, which Fredericson postulates as increasing tension and friction on the ITB. Myofascial restrictions and inflexibility can increase stress in the posterior ITB, particularly with the tensor fascia lata. Tightness in the hip flexors (iliopsoas), extensors (gluteal muscles), and rotators (particularly piriformis) can shift more load to the abductors and adductors. Weaker hip abductors eventually fail under continuous stress. PathophysiologyA small recess is formed between the lateral femoral epicondyle and the ITB as it travels along the lateral thigh to the tibial plateau. This space was believed to have a separate bursa lying deep to the band, but studies have revealed it to be synovium that is a lateral extension and invagination of the actual knee joint capsule (lateral synovial recess). Histologic analysis demonstrates inflammation and hyperplasia in the synovium, while MRI studies have demonstrated diffuse signal abnormality below the band and in the synovium but not in the ITB. This suggests that this syndrome is not a tendinopathy. Variance is observed in the congenital thickness of the band, so patients with thicker bands may be predisposed to ITBFS. ClinicalWhile pain is localized along the lateral knee, it also can include the hip. Pain is worse with downhill running and becomes worse with activity after a pain-free start. Pain may radiate from knee proximally or distally. Most individuals experience pain only during activities; however, individuals may experience pain with walking as the syndrome progresses. Tenderness is over the lateral knee, with a tender point at the lateral femoral condyle, approximately 1-2 cm proximal to the lateral joint line. Pain can be elicited with active flexion-extension of the knee within the first 30° while the thumb presses over the epicondyle and ITB. Crepitation may be felt. Restriction in hip adduction indicates tightness in the ITB and tensor fascia lata. In evaluating for ITBFS, also look for restrictions in iliopsoas, rectus femoris, gastrocnemius, and soleus function. Examination usually reveals restriction of hip adduction and weakness of the hip abductors, specifically the gluteus medius. Myofascial restrictions can mimic ITBFS, and these restrictions can be identified with a careful examination. Trigger points along the vastus lateralis, biceps femoris, and gluteus minimus can refer pain to the lateral knee, while fascial adhesions of the posterior ITB can generate pain as well. Careful palpation of these points can differentiate ITBFS from myofascial trigger points. The following provocative tests may be helpful:
INDICATIONSFailure of conservative therapy is an indication for surgery. Conservative therapy includes rest, stretching and strengthening exercises, anti-inflammatory medication, other therapy modalities, and biomechanical correction of limb length discrepancies and pes planus. A minimum trial of 3 months should be given before considering surgery. Even then, surgery is best withheld for highly motivated people who want to return to their sport or activity. RELEVANT ANATOMYThe ITB originates from the outer lip of the anterior iliac crest, anterior border of the ilium, and outer surface of anterior superior iliac spine. The tensor fascia lata originates here also, and its fascia blends with the ITB at the lateroanterior thigh one third of the way distally. The intermuscular septum connects the ITB to the linea aspera femoris until inserting just proximal to the lateral femoral condyle. From there, it passes in its broad expansion between lateral aspect of patella and biceps femoris to insert into the Gerdy tubercle, off the lateral tibial plateau. This expanse helps the lateral collateral ligament and posterolateral capsule to stabilize the knee. The primary synergistic muscles are the hip abductors. These muscles are the gluteus medius, gluteus minimus, and upper fibers of the gluteus maximus. Their nerve supply comes from the superior gluteal nerve, which is a branch off of the L4, L5, and S1 nerve roots. CONTRAINDICATIONSActive infection and coagulopathy are contraindications to surgery. WORKUPLab Studies
Imaging Studies
Diagnostic Procedures
Histologic FindingsTissue from the lateral synovial recess demonstrates hyperplasia and inflammation. ITB tissue may exhibit tendinosis. TREATMENTMedical therapyThe basic principles of treatment include control of inflammation, modification of activity, and correction of underlying problems. An aggressive treatment program is as follows: Acute phase
Subacute phase
Recovery phase Progressive strengthening exercises are started to restore muscle strength lost from inhibition and disuse. Exercises include side-lying leg lifts, pelvic drops, and step-down exercises. Return to running The angle of the knee during faster-paced running is beyond the friction point of ITBFS, so the patient should start with easy sprints on even surfaces, no more than every other day at first. The patient may gradually increase distance and frequency according to tolerance. Time to return to sports depends on the initial severity. Patients who return must first perform all strength exercises and stretches without pain. Most people return to their sport or running within 4-6 weeks. Surgical therapySurgery is used to resect a small triangular portion of the posterior ITB over the lateral femoral epicondyle. Studies demonstrated positive results with the knee flexed at 30° during the procedure. A resection of the underlying synovial tissue can also be performed, but some question exists as to whether it should be resected. Resection can cause chronic synovial fluid effusion in the recess and hematoma formation. Several studies state that tissue resection deep to the ITB is optional but not typically recommended. Preoperative detailsThe patient is restricted to taking nothing by mouth at least 8 hours before the procedure. ITB resections also can be performed through an arthroscopic procedure, and the patient is prepared for surgery similar to that for any such procedure. Otherwise, a tourniquet is applied to provide adequate hemostasis. Anesthesia can be achieved by general or epidural administration. The affected leg is positioned so that the lateral femoral condylar region is exposed. Intraoperative detailsWith the knee in 30° of flexion, a longitudinal incision is made centered over the lateral epicondyle. The posterior portion of the ITB is then exposed. The knee is flexed and extended to identify the portion of the ITB that is impinging on the lateral epicondyle. A triangular piece of the ITB is then resected. The base of the triangle is approximately 2 cm and centered over the posterior fibers of the ITB. The height of the triangle is roughly 1.5 cm. The knee is then moved through the full range of motion to confirm adequate release of the ITB. The wound is then irrigated and closed. Excision of an elliptical section of the ITB also has been described. Postoperative detailsSome controversy exists regarding postoperative immobilization. Martens et al advocated splinting the knee in extension for 1 week postoperatively followed by a gradual return to activity. In a study by Holmes et al, a soft dressing was applied and bicycling was allowed on postoperative day 3. In this study, 9 of 21 patients developed a small seroma near the lateral incision, which subsequently resolved with rest and icing. Follow-upSurgical release of the ITB is typically successful in eliminating pain. Athletes are able to return to their normal activities with a rehabilitation program in 3-7 weeks. For excellent patient education resources, visit eMedicine's Foot, Ankle, Knee, and Hip Center; Arthritis Center; and Bone Health Center. Also, see eMedicine's patient education articles Knee Pain and Knee Injury. COMPLICATIONSPotential complications include recurrent swelling in the lateral synovial recess, persistent bleeding, bisection of the ITB, infection, seroma, recurrent pain, and impingement. OUTCOME AND PROGNOSISMost patients with ITBFS recover with conservative therapy and enjoy good prognoses. One study in 1992 documented 19 athletes with ITBFS, and all were treated successfully without surgery. Those for whom surgery is eventually performed are patients who are motivated to return to a specific activity in which ITBFS limits or prohibits their participation. Those who require surgery often do well. Nemeth described 17 cases of ITBFS recalcitrant to conservative therapy, and 11 had excellent results from surgical treatment at 2-year follow-up. Firer reported 94% excellent or good results in 64 runners surgically treated after failure of conservative therapy. FUTURE AND CONTROVERSIESWith the increasing understanding of human biokinetics, health professionals are able to spot flaws in training, environment, and biomechanics quickly and avert significant disability with ITBFS. Biomechanical screenings can be used to identify predisposing factors and correct them before symptoms ever develop. Aggressive intervention, particularly with athletes and industrial workers, can resolve the problem before it becomes disabling. MULTIMEDIA
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Iliotibial Band Friction Syndrome excerpt Article Last Updated: Jun 1, 2005 | |||||||||||||||||||||||||||||||||||