Iliotibial Band Syndrome (ITBS).

Iliotibial Band Syndrome (ITBS), often called iliotibial band friction syndrome, is another common knee condition seen in endurance athletes (runners, triathletes, cyclists). The incidence is reported to be as high as 12% of all running-related, overuse injuries. Iliotibial band (ITB) is a sheet of connective tissue originating at the iliac crest and terminating at Gerdy’s tubercle and the fibular head. The post will cover current concepts in regards to the causes, history, risk factors, diagnosis and treatment of the ITBS.
ITBS in a non-traumatic overuse injury caused by friction/rubbing of the distal portion of the iliotibial band over the lateral femoral epicondyle (LFE) with repeated flexion and extension of the knee. The pathogenesis of ITBS involves inflammation (recently questioned) and irritation of the lateral synovial recess, as well as continued irritation of the posterior fibres of the ITB and inflammation of the periosteum of the LFE. It is suggested that with repetitive soft tissue irritation there is simply not enough time for the body to repair these damaged tissues. 
Athletes may present with sharp pain or burning at the lateral knee during running, cycling or hiking. Athletes typically start their activity pain-free, but develop symptoms after reproducible time or distance. Usually, symptoms cease shortly after activity but return with the next run/cycle. It is often noted by patients that running downhill or sitting with knees flexed for a long period of time, aggravates pain. Occasionally, pain or paresthesia extend along the  length of the band. Crepitation, snapping, or mild pitting oedema can occur over the affected area.    
Physical examination reveals tenderness of the ITB overlying the lateral femoral condyle as well as tight iliotibial band with Ober’s test. Pain may be elicited with the Noble compression test. Imaging usually not indicated when diagnosis is strongly suspected on clinical examination. MRI may show thickened iliotibial band and associated edema.  
The differential diagnosis for lateral knee pain includes primary myofascial pain, patellofemoral stress syndrome, early degenerative joint disease, joint sprain, popliteal or biceps femoris tendinitis, peroneal nerve injury and referred pain from the lumbar spine.

Potential risk factors include: tight ITB, tight gastrocnemius and soleus muscles, excessive ankle pronation, pes planus, leg length discrepancies, increased landing forces, increased knee internal rotation, low hamstring strength as compared to the quadriceps strength on the same side,  genu recurvatum. Training factors related to this injury include excessive running in the same direction on a track, greater-than-normal weekly mileage and downhill running. Studies have also demonstrated that weakness or inhibition of the lateral gluteal muscles is a causative factor in this injury. When these muscles do not fire properly throughout the support phase of the running cycle, there is a decreased ability to stabilise the pelvis and eccentrically control femoral abduction. As a result, other muscles must compensate, often leading to excessive soft tissue tightness and myofascial restrictions.

Conservative management include ice, ultrasound, deep friction massage, stretching, non-steroidal anti-inflammatory drugs (NSAID), corticosteroid injections (in severe cases), rest, shockwave therapy, hip musculature strengthening, activity modifications (cyclists may need to consider changing cycling position, saddle height, or pedal/cleat system).