At a glance......
- 1 Alternative Names
- 2 Anatomy Of Iliotibial Band Syndrome
- 3 Mechanism of Injury of Iliotibial Band Syndrome
- 4 Causes of Iliotibial Band Syndrome
- 5 Symptoms of Iliotibial Band Syndrome
- 6 Physical examination
- 7 Treatments Iliotibial Band Syndrome
- 8 Longer-Term Treatment of Iliotibial Band Syndrome
- 9 How is Iliotibial Band Friction Syndrome Treated?
- 10 Exercise for Iliotibial Band Syndrome
- 11 Prevention of IT Band Syndrome
Iliotibial band syndrome is a common condition that usually presents as pain on the outer side of the knee. The IT Band is a thick band of connective tissue that crosses the hip joint and extends down the outer thigh and attaches just below the outer side of the knee. IT Band syndrome is caused by excessive friction at the distal portion of the IT Band as it rubs over the outside portion of the knee. This is most common in runners and cyclists, but also other sports that involve repetitive knee bending because it leads to inflammation in this area.
The iliotibial band tract or IT band (ITB) is a longitudinal fibrous sheath that runs along the lateral thigh and serves as an important structure involved in lower extremity motion. The ITB is also sometimes known as Maissiat’s band. The ITB spans the lower extremity on its lateral aspect before inserting on Gerdy’s tubercle on the proximal/lateral tibia.
Proximally in the thigh, the ITB receives fascial contributions from the deep fascia of the thigh, gluteus maximus, and tensor fascia lata (TFL).[rx] The TEFL is the deep investing fascia of the thigh, encompassing the muscles of the hip and lower extremity around this region.[rx] Distally, the ITB becomes a distinct soft tissue layer of the lateral knee.[rx]
Iliotibial Band Syndrome (ITBS) has commonly been thought of as an overuse injury in runners. The exact etiology of ITBS is not well understood and there is no consensus on how to properly manage it. The purpose of this case series is to present a comprehensive model that utilizes a review of the current literature and the concept of regional interdependence as a foundation for the treatment of ITBS in runners.
Anatomy Of Iliotibial Band Syndrome
Origin, insertion, and structure
The detailed anatomic structure of the ITB, TFL, and its origins, insertions, and variations have been debated for decades in the literature.[rx]
The proximal IT track begins as three distinct layers coursing distally to fuse/coalesce at the level of the greater trochanter (GT)
Superficial IT layer:
- Origin: Ilium (superficial to the TFL origin)
Intermediate IT layer:
- Origin: Ilium (distal to the TFL origin)
- The intermediate layer’s location is consistently deep to the TFL muscle layer
Deep IT layer[rx]:
- Recognized as a constant structure
- Portions of the deep IT layer are also confluent with the hip joint capsule itself
- Origin: arises from the supra-acetabular fossa between the hip joint capsule and the reflected head of the rectus femoris
- Separate origin of TFL fibers originates off the ilium and in between the superficial and intermediate IT layer origins
- Distally, the TFL becomes a tendinous structure as it merges with the superficial and intermediate IT layers
- Farther distal, the TFL tendinous fibers, including the superficial and intermediate IT layers, fuse as a single confluent structure near the level of the GT
Gluteal aponeurotic fascia:
- Originates from the posterior iliac crest
- Courses distally to invest the anterior two-thirds of the gluteus medius
- A portion of its fibers merge with the posterior ITB to continue distally while the remaining aponeurotic fibers insert at the gluteal tuberosity on the femur
In addition, the posterior ITB also receives distinct fascial/tendinous contributions from:
- Superior gluteus maximus
- Superficial fibers of the inferior gluteus maximus
- Deep fibers from the inferior gluteus maximus course toward the femur to insert onto the gluteal tuberosity of the linea aspera
Proximal to the knee joint, the ITB attaches to the intermuscular septum and supracondylar tubercle of the femur. Proximal to the lateral epicondyle, there is an interposed fat layer between the ITB and the vastus lateralis.[rx] The ITB is more tendinous proximal to the lateral femoral epicondyle, and at the level of the epicondyle, the ITB contributes to lateral knee stability secondary to its anatomic position, intimal contact with the epicondyle, and relative to its location with respect to the lateral collateral ligament (LCL).[rx]
Proximal ITB function includes[rx]:
- Hip extension
- Hip abduction
- Lateral hip rotation
Distally, ITB function depends on the position of the knee joint[rx]
0 degrees/full extension to 20 to 30 degrees of flexion
- Active knee extensor >The ITB lies anterior to the lateral femoral epicondyle
20 to 30 degrees of flexion to full flexion ROM
- Active knee flexor >ITB lies posterior relative to the lateral femoral epicondyle
Mechanism of Injury of Iliotibial Band Syndrome
Friction occurs when the knee bends during running in soccer and the tendon moves back and forth across the distal femur (along the outside). This results in localized symptoms of tendinitis. This friction can be magnified by:
- increased training (especially running hills or too much too soon)
- poor shock absorption from shoes or rigid feet
- bio-mechanical malalignment
Soccer activities that involve prolonged running can cause the ITB over the insertion (lateral femoral condyle) to become irritated and inflamed. Factors contributing to this condition are:
- genu varum (bow legs)
- pronation of the foot (foot collapses inward)
- leg length discrepancy
- running on a banked surface
Causes of Iliotibial Band Syndrome
This injury is most often the result of overuse, especially for runners and cyclists. The longer distance you run or cycle, the more likely you are to experience this syndrome. For these two physical activities, bending the knee over and over again can create irritation and swelling of the iliotibial band.
Certain factors can make you more prone to developing Iliotibial Band Friction Syndrome:
- Muscle Tightness – Tightness in the leg muscles and the Iliotibial Band itself increases the friction on the ITB. Visit the knee stretches section for simple tests to see if your muscles are tight
- Muscle Weakness – Weakness in the buttock muscles (glutes) puts more strain on the Iliotibial Band, increasing your chances of developing Iliotibial Band Syndrome
- Flat Feet – If you have flat feet (dropped foot arches) it slightly changes the angle of the leg, putting more friction through the Iliotibial Band
- Excessive long distance or hill running – Overuse can also lead to Iliotibial band syndrome due to repetitive friction. Hill running puts even more tension through the ITB
- Running on a sloped surface – Lots of running surfaces e.g. roads and running tracks are slightly banked. The foot position on the lower leg causes the Iliotibial band to be stretched
- The sudden increase in activity – Someone who rapidly increases their training is at risk of developing Iliotibial Band Syndrome due to the sudden increase in friction at the knee
- Leg Length Discrepancy – If one leg is slightly shorter than the other it puts more strain on the Iliotibial Band
- Bowlegs – The curved nature of bow legs means there is a larger than normal space between the knees. This puts extra stretch on the Iliotibial Band
Other Causes Include
- Being in poor physical condition, including a lack of strength and flexibility, especially a tight iliotibial band
- Not warming up before exercising
- Having bowed legs
- Having arthritis of the knee(s)
- Poor training techniques, including sudden changes in the amount, frequency or intensity of workouts, as well as inadequate.
- Poor training techniques
- Large Q angle
- Sacroiliac joint dysfunction
- Genu valgum ( knock kneed)
- Leg length discrepancies
- Strength imbalances in the hip inductors
- Spending long periods of time/regularly sitting in lotus posture in yoga. Esp beginners forcing the feet onto the top of the thighs
- Consistently running on a horizontally banked surface (such as the shoulder of a road or an indoor track) on which the downhill leg is bent slightly inward, causing extreme stretching of the band against the femur
- Inadequate warm-up or cool-down
- Excessive up-hill and down-hill running
- Positioning the feet “toed-in” to an excessive angle when cycling
- Running up and down stairs
- Hiking long distances
- Treading water
Symptoms of Iliotibial Band Syndrome
- Sharp pain – People with IT band syndrome typically experience sharp pain at the outside of the knee joint, either at or just below the rounded end of the thighbone, called the lateral femoral epicondyle, or just femoral condyle.
- Pain when the knee is bent 30 degrees – IT band syndrome pain is usually most noticeable when the knee is bent at about 30 degrees—this is when experts theorize the IT band passes over the femoral condyle.
- Tightness and loss of flexibility – The outside of the thigh feels tight and hip and knee may be less flexible.
- Tenderness – The outside of the knee is tender and pressing against it may cause pain.
Pain when running – IT band syndrome is the second most common injury for runners.
- Running on a decline can be especially irritating for runners.
- A runner typically feels a sharp pain when a foot hits the ground or right afterward.
Pain when cycling – Cyclists will typically feel the pain come and go during the downward pedal stroke and again during the upward pedal stroke when the knee is bent at 30 degrees.
- Pain, tenderness, swelling, warmth, or redness over the iliotibial band at the outer knee (above the joint); may travel up or down the thigh or leg
- Initially, pain at the beginning of an exercise that lessens once warmed up; eventually, pain throughout the activity, worsening as the activity continues; may cause the athlete to stop in the middle of training or competing
- Pain that is worse when running down hills or stairs, on banked tracks, or next to the curb on the street
- Pain that is felt most when the foot of the affected leg hits the ground
- Possibly, crepitation (a crackling sound) when the tendon or bursa is moved or touched
- Stabbing or stinging pain along the outside of the knee
- A feeling of the ITB “snapping” over the knee as it bends and straightens
- Swelling near the outside of your knee
- Occasionally, tightness and pain at the outside of the hip
- Continuous pain following activity, particularly with walking, climbing, or descending stairs, or moving from a sitting to a standing position
- Pain that is worse when running down hills or stairs.
- Pain that is felt most when the foot of the affected leg hits the ground.
- Possibly, a crackling sound when the ITB or bursa is moved or touched.
There is usually tenderness on palpation of the iliotibial band (ITB) 2 to 3 cm superior to the lateral joint line. In mild cases, results of an examination may be normal, but in severe cases, there may be local edema or crepitation. Noble’s, Ober’s, and modified Thomas’s tests are used in the diagnosis, but are provocative tests used in the physical examination, and not true diagnostic tests. Noble’s test is often positive.
- Noble’s test – Physician applies pressure over the lateral femoral epicondyle while extending the knee from 90° of flexion. Pain occurs when the knee is flexed at around 30°.
- The force of hip abduction – The force of hip abductors can be decreased. These muscles should thus be tested.
- Treadmill test – This test is described in several studies as a valid, effective, and sensitive method of evaluating the effects of treatments for running-related pain and is used to measure the amount of pain that subjects experience during normal running. If this includes pain to the lateral side of the knee, the test is considered positive.
- Noble compression test – This test starts in supine posture and knee flexion of 90 degrees. As the patient extends the knee the assessor applies pressure to the lateral femoral epicondyle. If this induces pain over the lateral femoral epicondyle near 30-40 degrees of flexion, the test is considered positive. A goniometer is used to ensure the correct angle of the knee joint.
- Ober’s test – The patient lies down with the unaffected side down and the unaffected hip and knee at a 90° angle. If the ITB is tight, adducting the leg beyond the midline is difficult and the patient may experience pain at the lateral knee. Normal tightness is when the leg can be passively stretched to a position horizontal but not completely addicted to a table. Moderate tightness is when the leg can be passively adducted to horizontal at best. If the leg cannot be passively adducted to horizontal, this is maximal tightness.
- Modified Thomas’s test – The patient sits on the end of an examining table, rolls back to a supine position, and holds both knees to the chest. The patient holds the knee on the asymptomatic side close to the chest, keeping the hips on the table, and avoiding excessive posterior tilt. The examiner then slowly lowers the affected limb towards the floor. The test is positive if the angle of the femur is below horizontal.
- MRI or ultrasound – may be requested if there is doubt about the diagnosis from the physical examination.The result may be normal, or show cystic changes (ultrasound) or poorly defined signal intensity (MRI) changes under the ITB.
- MRI of the hip without contrast – may be indicated if initial knee x-rays are non-diagnostic (demonstrate normal findings or a joint effusion), or show osteochondral injuries (fracture/osteochondritis dissecans or a loose body), avascular necrosis, or internal derangement (e.g., Segond’s fracture, deep lateral femoral notch sign)
Treatments Iliotibial Band Syndrome
Whether using a foam roller or not, patients can benefit from making changes in their stretching and exercise routines.
- Rest – People with IT band syndrome may need to cut back on the intensity, duration and frequency of activity that leads to IT band pain (for example, reduce running or cycling mileage). People with moderate to severe IT band pain may need to take time off from their sport. It can be frustrating and difficult for active people to cut back on their training schedules; however, rest is necessary for the injury to heal.
- Warm-up – Five to 10 minutes of gentle exercise and stretching can literally increase the body’s temperature, helping muscles become more elastic and responsive and reducing the chance of IT band syndrome or other injuries.
- Change footwear – Switching out shoes and/or getting orthotic inserts can alter a person’s biomechanics and reduce the risk of IT band pain.
- Massage – Much like the foam roller exercise, massage may help relieve tension and improve blood flow in the IT band, thereby reducing pain.
- Stretching – A doctor may recommend stretching or yoga to promote flexible muscles and other soft tissue.
- Change running biomechanics – Runners may consider shortening their stride6 and running on soft, flat surfaces, such as tracks and even, grassy trails.
- Change cycling biomechanics – Cyclists may consider adjusting saddle position and pedal clips. Even a small adjustment can alter the biomechanics of their pedaling and reduce IT band pain.
- Ultrasound – Efforts to heal the IT band and reduce pain may get a small boost from ultrasound and electrical muscle stimulation.7
- Iontophoresis – Doctors and physical therapists occasionally recommend iontophoresis, which uses a mild electrical current to administer an anti-inflammatory medicine (e.g. dexamethasone) through healthy skin and into the sore area. This treatment may be appropriate for people who can’t tolerate injections or want to avoid injections.
- Medication – Common pain remedies such as aspirin, acetaminophen, ibuprofen, and naproxen can offer short-term relief. All are available in low doses without a prescription. Other medications, including muscle relaxants and anti-seizure medications, treat aspects of spinal stenoses, such as muscle spasms and damaged nerves.
- Corticosteroid injections – Your doctor will inject a steroid such as prednisone into your painful area. Steroids make inflammation go down. The corticosteroid will provide prolonged anti-inflammatory protection by inhibiting the inflammatory mediators. Patients will most likely be symptom-free within days to weeks without treatment.[rx]
- Anesthetics – Used with precision, an injection of a “nerve block” can stop the pain for a time.
- Muscle Relaxants – These medications provide relief from spinal muscle spasms.
- Neuropathic Agents: Drugs(pregabalin & gabapentin) that address neuropathic—or nerve-related—pain. This includes burning, numbness, and tingling.
- Opioids – Also known as narcotics, these medications are intense pain relievers that should only be used under a doctor’s careful supervision.
- The lidocaine – will help by providing immediate relief from the pain by blocking the sodium channels in the surrounding tissue, inhibiting the transmission of the pain signal
- Topical Medications – These prescription-strength creams, gels, ointments, patches, and sprays help relieve pain and inflammation through the skin.
- Calcium & vitamin D3 – to improve bone health and healing fracture.
- Glucosamine & diacerein – can be used to tightening the loose tension and regenerate cartilage or inhabit the further degeneration of cartilage.
Longer-Term Treatment of Iliotibial Band Syndrome
Long-term treatment aims to address the cause of the Iliotibial Band Syndrome and may include
- Strengthening Exercises – Strengthening the glutes, quads, and hamstrings improves how the hip and knee function which reduces the friction on the Iliotibial Band. Visit the knee strengthening section for exercises that will help
- Stretching Exercises – Stretching the quads, hamstrings, and ITB also helps reduce the friction at the knee. Visit the stretches section to see if tight muscles are likely contributing to your Iliotibial Band Syndrome
- Knee Straps – Wearing a brace that straps around the top of the knee direct forces away from the Iliotibial band so can be very helpful to reduce irritation when running. Visit the knee transaction to see what your options are
- Taping – Taping can also be used to reduce the forces going through the ITB – see you physical therapist/ sports injury specialist for more information
- Massage – Deep tissue massage to the Iliotibial Band can reduce tightness, but it can be quite painful
- Injections – If other treatments have failed, a cortisone injection can be given to help reduce pain and inflammation. However, it should always be accompanied by strengthening and stretching exercises to ensure the problem doesn’t return
- Orthotics – Special insoles can be worn in your shoes to correct poor foot positions such as flat feet. See an orthopedist for a full assessment and advice
How is Iliotibial Band Friction Syndrome Treated?
As described by Fredericson and others, the accepted treatment of iliotibial band friction syndrome follows the outline common to the treatment for many connective tissue injuries, beginning with treatment of the acute inflammatory response and progressing through a corrective treatment phase and ultimately to a return to regular activity [rx].
Acute phase treatment to limit the inflammatory response
- Care in the acute phase focuses on activity limitation or modification, and measures to relieve pain and inflammation, such as ice, oral NSAID’s, or corticosteroids delivered via phonophoresis or injection.
- There is a limited body of research establishing the effectiveness of any of these measures in ITBFS. Ellis et al., in a review of published trials of therapy for ITBFS, found only one prior study of adequate quality that tested the use of NSAIDs, and two other studies that focused on the use of corticosteroids, in one case applied via phonophoresis and in the other via injection. In all three studies, the improvement was demonstrated in both the control group and the treatment group, but the groups receiving anti-inflammatory agents showed significant improvement compared to those that did not [rx].
- On the other hand, other research, not specific to ITBFS, points to the risks of these anti-inflammatory measures when treating connective tissue injuries, and raises the possibility that the pharmaceutical limitation of the inflammatory stage in connective tissue injury actually leads to a delay in healing or to poorer healing [rx, rx].
Stretching of the Iliotibial Band and Related Structures
- Stretching of the iliotibial band, lateral fascia, gluteus medius, and other muscles are frequently recommended as part of the treatment plan for ITBFS.
- A variety of stretching protocols have been suggested. Frederickson measured the change in length of the iliotibial band while athletes performed variations of ITB stretches, and found that a particular stretch—with the athlete standing, placing the affected foot adducted and behind the other, and laterally flexing away from the affected side with the arms stretched overhead—created the greatest lengthening of the band [rx]. On the other hand, Falvey et al. found that the optimal stretch varied considerably from individual to individual [rx].
Connective Tissue Manipulation
Manual therapy techniques to release myofascial restrictions in the iliotibial band and related structures are also frequently recommended.
- Pedowitz reported on a single case that he treated effectively with strain–counterstrain technique [rx]. Hammer emphasizes the use of connective tissue treatment methods to release restrictions not only in the ITB but in the gluteal muscles and any other areas found to be restricted in the hip area, thigh, or lower extremity [rx]. Frederickson agrees that treatment of trigger points in the band can help significantly [rx].
- On the other hand, of the scarce published data that has tested the efficacy of these measures, Ellis et al. found a single trial of deep transverse friction massage used in the treatment of ITBFS. It was not found to confer any added benefit [rx].
Strengthening of the Hip Abductors
- Though no trials have been published on the efficacy of strengthening exercises in the treatment of ITBFS, strengthening of hip abductors is often recommended [rx].
Improved Neuromuscular Coordination
- Improving neuromuscular control of gait is also frequently mentioned as a useful approach in the treatment of ITBFS. Fredericson et al. depicted a number of exercises to train complex multi-dimensional movement patterns involving weight shift and other aspects of hip abductor function [rx]. Pettit and Dolski also described the successful application of a multi-dimensional corrective therapeutic exercise program combined with stretching, massage, soft tissue mobilization, shoe modification, and electrical stimulation [rx].
Surgical Excision of a Cyst, Bursa, or Lateral Synovial Recess
- Practitioners utilizing conservative means report a satisfactorily high rate of positive response so that few patients should require surgical intervention [rx, rx–rx]. Yet a number of case series reporting resolution of ITBFS from the surgical excision of a bursa, cyst, or portion of a lateral synovial recess have been published [rx–rx, rx].
Exercise for Iliotibial Band Syndrome
Side Leg Raaise
Lie on your right side with both legs straight. Slowly raise your left leg about 45 degrees, then lower. Repeat on both sides. To make this move more challenging, use an exercise band around your ankles to increase resistance. Reps: 20–30 on each side
Lie on your right side with your knees bent at a 90-degree angle to your torso. Keeping your feet together, use your glutes to slowly open and close your legs like a clamshell. Keep the motion controlled, and don’t allow your pelvis to rock throughout the movement. Use an exercise band just above your knees to increase resistance. Reps: 20–30 on each side
Lie on your back with your arms at your sides, knees bent and your feet on the floor. Pushing your heels into the ground, use your glutes to raise your pelvis up until your body forms a straight line from your knees to your shoulders. Lower slowly, then repeat. For a more advanced version, raise one leg into the air and perform the same exercise with each leg individually. Reps: 20–30 on each side
Side Hip Bridge
Lie on your side with your feet elevated 1–2 feet off the ground on a stable surface. Lift your torso using your hip muscles while keeping your spine stable, then lower slowly. Reps: 10–30 on each side
Stand with your legs about hip-width apart with an exercise band around your ankles. Take 10 steps to the right, then 10 back to the left. This is one set. The exercise band should remain tight enough to provide resistance throughout the entire movement. Reps: 3–5 sets
Stand on your right leg with your left knee raised out in front of you. Slowly lower yourself, balancing on your right leg and allowing your left leg to straighten out in front of you. Try to lower yourself until your quad is just about parallel with the floor, then slowly come back up. Reps: 5–15 per leg
Stand on your right foot. Start with your pelvis in a neutral position, and then drop the left side so it is several inches below the right side of your pelvic bone. Use your right hip muscle to lift your left side back to its neutral position. Reps: 10–30 on each side
- This is extremely rare and is only considered if all other treatments have failed. It is done arthroscopically (keyhole surgery) and aims to break down any scarring in the tissues and if necessary lengthen the Iliotibial band to reduce the friction at the knee.
- Surgery is often reserved for refractory cases that have failed other avenues of conservative management. However, in the athletic population, return to sport is a common concern, and multiple, long absences from the sport due to trials of various conservative treatment approaches are often not ideal.
- There are differing viewpoints as to when surgical treatment should be implemented. Martens et al. suggest that conservative treatments should be maintained for an average of 9 months before consideration of surgical intervention [rx]. Others have based their decision for surgical intervention on the observation that at 30 degrees flexion, the posterior fibers of the ITB are tighter against the lateral femoral epicondyle than are the more anterior fibers, in which case a surgical release in the posterior fibers is needed to correct the problem [rx, rx].
- Bursectomy has also been explored as a surgical treatment option for ITBS. In a recent study, a single surgeon performed 11 open iliotibial band bursectomies on 11 patients (7 M, 4 W). Each patient presented with persistent (>6 months) symptoms despite conservative treatment, with an average age at onset of 29 (24–41) years [rx]. After a minimum of 20-month followup, all patients were able to return to their preinjury Tegner activity levels, and all reported less pain (11-point visual analogue scale score decreased by 6 points) . Nine of the 11 patients said that knowing what they know now they would have the surgery performed again for the same problem. This population, however, was a mix of athletic and the general population, and the study did not separate out the results of each population.
Prevention of IT Band Syndrome
Here are some steps you can take to prevent iliotibial band syndrome:
- If you have IT Band tightness, using a foam roller regularly is one of the best things you can do at home to help relieve your pain.
- It’s important to change your running shoes every 300 to 500 miles or every 3 to 4 months. Worn shoes absorb less shock which may lead to an increased incidence of IT Band pain. If you run lots of miles, consider alternating between two pairs of shoes to allow 24 hours for the shoe’s shock-absorbing cushion to return to its optimal form before running in them again.
- It’s important to add mileage and intensity very slowly to let your body adjust to the demands of running. Doing too much, too soon is a very common cause of overuse injuries.
- Hill running, particularly downhill running, increases friction on the IT Band and is tough on the quadriceps. As the quads fatigue, they lose the ability to stabilize and control the knee tracking position, which also increases stress on the IT band.
- If you are prone to knee pain, be careful of the surface you run on. Graded or angled surfaces often increase strain and tension on the IT Band of the downhill leg.
- Many athletes fail to protect the knees adequately in cold temperatures. The IT Band is particularly susceptible to the cold and experts recommend that athletes keep the knees covered during sports when the temperatures are below 60 degrees.
- Use a foam roller to release the IT Band after exercise, when the muscles are warm and supple. If you have any IT Band tenderness or pain, apply ice after exercise as necessary to reduce inflammation and pain.
- Following some general guidelines will help you prevent IT Band Syndrome, as well as many other common sports injuries.
- Most importantly, always decrease your mileage or take a few days off if you feel pain on the outside of your knee.
- Walk a quarter- to half-mile before you start your runs.
- Make sure your shoes aren’t worn along the outside of the sole. If they are, replace them.
- Run in the middle of the road where it’s flat. (To do this safely, you’ll need to find roads with little or no traffic and excellent visibility.)
- Don’t run on concrete surfaces.
- When running on a track, change directions repeatedly.
- Schedule an evaluation by a podiatrist to see if you need orthotics.