In general, there are two types of hip impingement: CAM morphology, which involves bony prominences on the neck of the femur near the joint, and pincer morphology, characterized by a malposition of the acetabulum in the form of retroversion or an overly pronounced labrum. However, a combination of both forms is most frequently encountered. It is important to know that FAI is very often an asymptomatic finding and altered hip anatomy does not necessarily lead to symptoms – even in athletes. However, studies show an increased risk of osteoarthritis in patients with FAI. Reiman et al. from 2015 assembled existing evidence on the diagnostic accuracy of the FADDIR test in a systematic review and found a pooled sensitivity of 99% and a low specificity of 5%. The conclusion was that the FADDIR test may be useful in exclusion screening for FAI, but diagnosis by the test is not possible. Furthermore, the quality of the included studies was moderate.

To perform the test, the patient lies supine. The patient’s leg is flexed to 90°, adducted and additionally positioned in internal rotation.
The test is positive if the hip/groin pain known to the patient is reproduced.

Other common orthopedic tests to assess for FAI and/or labrum tears of the hip are:

• Thomas Test
• Anterior Labral Tear Test
• Posterior Labral Tear Test
• McCarthy Test
• Foot Progression Angle Walking Test