Flexing the hip to 90 degrees, adducting, and internally rotating the hip, known as the FADDIR test, should also be performed. It is positive when it causes pain. The FABER test should also be performed, this test involves flexing, abducting, and externally rotating the hip. The FABER test is useful when diagnosing concurrently with a labral pathology and is considered positive if the position elicits pain. Additional non-invasive ways to observe possible FAI is changes in gait that include a lower peak hip extension and internal rotation to compensate for bony growth. X-ray
Projectional radiography ("X-ray")is often considered first line for FAI. Anterior-posterior pelvis and a lateral image of the hip in question should be attained. A 45-degree Dunn view is also recommended. Other modalities
MRI imaging may follow, particularly if there is no specific evidence on radiographs, producing a three-dimensional reconstruction of the joint for better definition, to evaluate the hip cartilage, or measure hip socket angles (e.g. the alpha-angle as described by Nötzli in 2-D and by Siebenrock in 3-D). MR arthrogram had been used in the past, as it was more sensitive for picking up soft tissue lesions; however, due to improvement in technology, MRI is now considered comparable for picking up such lesions. CT is not usually used due to radiation exposure and no benefit above MRI. It is possible to perform dynamic simulation of hip motion with CT or MRI assisting to establish whether, where, and to what extent, impingement is occurring. The diagnosis is often made in conjunction with a labral tear.
Femoroacetabular impingement (FAI) is a condition involving one or more anatomical abnormalities of the hip joint, which is a ball and socket joint. It is a common cause of hip pain and discomfort in young and middle-aged adults. It occurs when the ball shaped femoral head contacts the acetabulum abnormally or does not permit a normal range of motion in the acetabular socket. Damage can occur to the articular cartilage, or labral cartilage (soft tissue, ring-shaped bumper of the socket), or both. The condition may be symptomatic or asymptomatic. It may cause osteoarthritis of the hip. Treatment options range from conservative management to surgery. Signs and symptoms
Pain is the most common complaint in those with FAI. It is experienced in a number of areas, making the diagnosis challenging, but commonly occurs in the groin, upper buttock/lower back, the buttock or beneath the buttock, side of the affected hip and posterior upper leg. Onset of symptoms has been reported to present in both an acute and more gradual manner. The pain is often significant enough to cause a decrease in activity level and movement. Some will also describe decreased range of motion of the affected hip. Another symptom is groin pain associated with activity and no prior history of trauma. Inability to perform activities such as high hip flexion or prolong sitting can also be seen in individuals with FAI. Cause
FAI is characterized by abnormal contact between the proximal femur and rim of the acetabulum (hip socket).